MedWorm.com provides a medical RSS filtering service. Over 5000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'The Anterior Commissure' source. Sat, 16 Aug 2008 14:47:50 +0100 http://anteriorcommissure.blogspot.com/2008/01/new-blog-new-co-bloggers-new-location.html I just couldn't leave.My dear friend Jake from Pure Pedantry just made me an offer I can't refuse:Permanent guest blogger!I'll be posting there every so often, so please pay a visit :)Also, if you haven't picked up a copy of Open Lab 2007, please do - you can find one of my pieces there. Nature just published a review of the anthology; go check it out! (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=1173433 Wed, 23 Jan 2008 19:48:00 +0100 1173433 http://anteriorcommissure.blogspot.com/2007/12/fond-farewell.html This will be my last post on the AC.With both sadness and affection, I've decided to close shop. The AC will remain up for a while, so that people can browse old posts and update (if they choose) their RSS and blogrolls. As I'm just about to pass my one-year blog-versary (!), I figured now was as good of a time as any. This year, according to Technorati, there were 188 reactions to my posts, totalling an authority of 53 and rank of 143,900...right alongside all of the other bloggers who fill the 143,900th spot :)What started as a sort of poor-man's online journal club - a way to read and share the science that I find intriguing - has blossomed into a really beautiful experience for me. I've befriended a number of really excellent minds and caring people, and I will miss my interactions with them deeply.But, the past couple of months have left me busy enough to reduce my posting frequency (obvious to many of you) and engagement in the blogosphere. Now, it's time to finish my dissertation, find a postdoc, and focus my attention on our rapidly growing science lecture series which, if you're in the NYC area, you should drop by!So, for those of you still out there, THANK YOU for reading. Your comments have made me a better writer and a better thinker, and I've enjoyed the experience immensely.Below, a few parting photos from my recent trip to South America...mating- and reproduction-related, of course:Guanacos are close cousins of llamas, alpacas, and vicuñas - all camelids native to Chile and Argentina. Social groups come in a few forms, including a dominant male or two with many females and young, and reproductively immature or subordinate males (i.e. relatively young or old).In the first photo, this one looks solitary, but he/she was surrounded by a social group that included infants (next picture).To protect the infants, adult guanacos could be seen atop the surrounding hills, typically at their highest point, which acted as a lookout and enabled them to survey their surroundings and warn their social group of approaching predators.At one point, we saw one of these adults run at breakneck speed down the hill, holding its head very low. According to our guide, males are often seen running with their heads lowered, in order to bite other males' genitals and thus secure an advantage during mating season. Talk about taking the competition out of the running!These alpacas are obviously in captivity, but the baby at the bottom left is just too cute not to post :)These Andean flamingos were photographed in the salt flats of the Atacama desert in northern Chile, but cover a huge region - from Canada to the southern reaches of Patagonia. Apparently, flamingos are monogamous, laying a single egg with each successful mating experience. Both males and females produce a sort of fat-rich crop milk, which they will feed to the infant once the egg hatches.....Most of the wild donkeys in the Atacama desert are the ancestors of domesticated donkeys that lived in large mining towns in the late 1800s. When some of the mining collapsed, the miners and their families vacated with only the possessions that they could carry, leaving behind ghost towns...and their donkeys. I was thrilled to capture the photo of this female with her nursing infant on our second day there. Even on vacation, I couldn't stay away from maternal behavior. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=1119354 Thu, 27 Dec 2007 22:52:00 +0100 1119354 http://anteriorcommissure.blogspot.com/2007/11/careful-what-you-seeas-not-all-moms-are.html Laelaps, one of my regular reads, recently posted a number of videos depicting what have been cutely described as "interspecies parental care." Appropriately, he mentioned the opposing sham-examples (see my post on this) that lend undue credibility to this phenomenon, and accurately mentioned that members of one species have been known to care for young of another species.Within limits, I'll accept this. But here's my caveat. Depending on the species, maternally responsive individuals (i.e. lactating, parturient females) are typically in a highly anxiolytic state; given recent exposure to their offspring, they are less fearful of threatening situations, novel stimuli, and intruders. If you'd present one of these maternally responsive individuals with offspring of a different species, you'd have the best chance of seeing the female act maternally - truly maternally - toward the offspring. A series of very early studies (1954-6) by Frank Beach showed that maternal female rats will pick up and retrieve rabbit and other small non-rodent offspring and bring them back to their nest for care...though not as fast or frequently as their own offspring. While I have no doubts about the strength of maternal motivation - it's my dissertation research - I question its translatability to other species.I'm not so sure about non-maternally primed animals. Here's a story to help explain why:Last year, researchers in France set out to determine whether foals responded positively to early human contact. Their surprising findings - that forced stroking/handling did not affect foals' subsequent interactions with humans later in life - forced them to an extremely important conclusion, that "interspecies differences may exist in how tactile stimulation is perceived...[which holds] important general implications in how we consider the development of social relations, both within and between species."So now, with our anthropomorphic selves in check:Could this "interspecies parenting" actually be tolerance of other non-self species? Curiosity? Could it reflect individual differences in basal corticosterone levels, resulting in a less anxious/fearful animal that is thus less inhibited in its approach and interaction with members of other species?I see two immediate ways in which non-maternal individuals might tolerate - not caretake, not act maternally toward, but tolerate interaction with - the young of other species:It's well-established that, within-species, the odors associated with infant offspring are highly aversive (i.e. a big turn-off) to non-maternal females and males. Perhaps these "interspecies parents" are simply non-maternal animals that are unresponsive odors elicited by the infants of non-self species.Age - both of the young and of the 'parental' individual - can be a critical factor in determining how individuals of the same species or different species interact. Young offspring of any species share more similarities when they're closer to their embryological state than when they're entering their juvenile state; it's well-established that younger offspring are more "likeable" to an adult of the same species (rats are a prime example) than are older offspring. Also, juvenile animals interact more readily with novel stimuli, such as same-species offspring*, than do adult animals; this has been attributed to basal hormone levels and environment-based learning, among others.Alternative explanations to this parenting 'phenomenon' abound, outside of the two described above. They get my vote.Or perhaps I'm just selling maternal motivation short.Thoughts?* remember, in the wild, if you're not perched atop a nest brimming full of young, you probably have no interactions with young on a day-to-day basis. think back to your undergraduate experience - how many kids did you see running around and/or were you able to interact with regularly? unless you were babysitting or had kids of your own, i'd venture to say 'not many.' same idea, for most animals in their natural environment. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=1063001 Fri, 30 Nov 2007 17:19:00 +0100 1063001 http://anteriorcommissure.blogspot.com/2007/11/single-female-antelope-seeks-submissive.html Another sexual reproduction theory bites the dust.According to behavioral ecologist Dr. Jakob Bro-Jørgensen, female topi (an African antelope) can become extreme aggressors when it comes to mating, a shift in status-quo reproductive theory in which males are relatively persistent and females are relatively resistent members of the mating duo.Every 1.5 months, a female topi is fertile and therefore becomes extremely sexually promiscuous, successfully mating with an average of four males with each male mounting her anywhere between 2-36 times (called intromissions). Females seek out and attempt to mate with males that have acquired the most territory in a breeding area - the mark of a studly topi - but will mate relatively indiscriminately if given the opportunity. And if there isn't an opportunity, a female will make one - at right is an image from the author's nice PNAS piece in which a female is revving up to head-butt a male who is attempting to mate with another female. Go get 'em!After all, for these females, a small window of fertility means that conception and pregnancy is serious business - if it doesnt' happen then, it won't again for a long while. Talk about upping the ante.So, given that a female topi's strategy is to mate with as many males as possible while fertile, how could male topis not be the happiest little antelopes to grace the savannah??As it turns out, the female mating strategy of "persistence wins out" doesn't benefit the male topi in the least. In fact, our most studly male topi, who mates inceccently during females' most fertile periods, may be at the greatest disadvantage. Males have limited stores of sperm, which are quickly depleted with multiple matings. And, to ensure the greatest likelihood of his offsprings' survival, male topi would prefer to practice more selective mating, in which sperm could be distributed in a more discriminative manner to the cutest female topi.In other words, males would prefer more choice in the matter.But, while males of other species can resist sexual advances more easily, the female topi is relentless. How? Simple: they push the males around!Pre-mating aggression is 10x more likely in dominant females than subordinate females. It comes as no surprise, then, that dominant females mate more often than subordinate females. By being pushy, a female can prevent a male from resisting by making her presence very, very conspicuous (a nice head-butt to the side will do that for you). But, if a male counter-attacks, say "so long" - while males only do so 7% of the time, he typically refuses the female as a mating partner, a harsh consequence.Wonder what a topi date would be like...There's also a nice writeup on other aspects of this article here.Images: female topis fighting here; female topi attacking a mating pair here.In case the pdf didn't work, find the abstract here. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=1063002 Fri, 30 Nov 2007 14:17:00 +0100 1063002 http://anteriorcommissure.blogspot.com/2007/11/body-shape-and-perceived-attractiveness.html The topic's become a veritable cottage industry, but I've been meaning to post on this for a while...Many people are already familiar with studies on perceived body attractiveness, with heterosexual males typically rating curvy female silhouettes as more attractive than thinner silhouettes. In fact, curvier females, represented by lower waist-to-hip ratios (WHRs), are rated more attractive by men from when adolescent hormones are ablaze until well into their 80s (!); it is no surprise that movie/magazine stars, Miss America winners, and, yes, even Playboy centerfolds have maintained a relatively low WHR over the past 50 years. Researchers hypothesize that a low WHR is associated with a female's youth, reproductive fitness, general health, and vulnerability to disease. Yet Singh (1993; see right) revealed that female physical attractiveness not only depended on a low WHR but also on her overall weight. Most undergraduate males rated the first female silhouette (0.7) in Row II as most attractive. Rows I and III represented underweight and overweight females, respectively, while Row II represents females of average weight. While the first females in each row, depicting the lowest WHR (0.7) were rated as most attractive in their row, the first females in Row II was rated as the ultimate cat's meow. Singh concluded that, as being extremely underweight or overweight can adversely affect a female's reproductive health (including normal menstruation), men may still be hard-wired to seek out the most fit partner for mating. Body-mass index (BMI) has since become a very hot topic in the perceived physical attractiveness of females, with much recent research suggesting that BMI is more strongly correlated with physical attractiveness than WHR.But, per everyone's favorite ratio, where does the difference lie - the waist or the hips?More recently, researchers manipulated the WHR of female silhouettes (see right) by either altering the female's waist size (top row) or her hip size (bottom row). While low WHR continued to be rated as most attractive, males were most responsive to changes in waist size. Researchers proposed that a female's waist size in conveys more information about her fertility and general health, arguing that:...waist size increases during pregnancy and in the post-reproductive period...indicating the fecundity status [fertility] of a woman...Visceral fat in the waist region can be a signal of higher morbidity risk...[and] the waist is a good indicator of sex hormones profiles.The relative importance of waist size over hip size may be a particular characteristic of developed or westernized societies, which are not threatened by food shortages or ecologically harsh conditions and thus do not value additional fat storage through the hip/thigh region. So, why do we explore the underpinnings of physical attractivenss in humans? That the characteristics by which we look for potential partners and mates still seem to retain an adaptive, evolutionary significance is quite intriguing, but how Western culture may (or may not) influence how we perceive physical attractiveness in the opposite sex is absolutely fascinating. And, adding an additional layer of complexity, some research suggests that self-report and physical (e.g. genital) responsivity to attractive figures are not necessarily correlated, indicating that we may not be all too in-tune with what we 'think' we find attractive, and what our bodies physically respond to. So, I'll be keeping my eye out for studies identifying any discrepancies between physical responses and self-report, the latter of which will be increasingly colored by social, cultural and historical influences. By minimizing the impact of these intervening influences, perhaps researchers will reveal additional layers of these residual, adaptive underpinnings that have contributed to our survival as a species for so long now... And perhaps along the way, we'll also figure out how all of those intervening influences can so easily trump physical attractiveness, when you meet a new Spice of Your Life. Which, in my book, is a much more intriguing question...Images: Figure 2, Singh (1993); Figure 1, Rozmus-Wrzesinska & Pawlowski (2005)Disclaimer: My intention is to discuss existing literature regarding female physical attractiveness. There are myriad issues surrounding perceived body size, physical traits considered attractive by same-sex/homosexual raters, sociocultural influences on body size, gender discrepancies in ratings of same- and opposite-sex attractiveness, intellectual/mental attractiveness, etc. Realizing the scope of this issue, I have purposefully neglected all of these issues, not due to ignorance but due to time/space constraints. I recognize the biases inherent to these studies, and yes, I agree that cartoon women depicted in the above figure do not perfectly represent weights or WHRs. For the purpose of this post, I ask you, simply, to go with it. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=1051351 Mon, 26 Nov 2007 16:15:00 +0100 1051351 http://anteriorcommissure.blogspot.com/2007/11/return-of-ac-again.html Yes, I'm still alive.I think I've finally been dragged back into the blogging world after a 3-week hiatus. Immediately after presenting my thesis proposal, I was in CA for a week and, since returning, have been working feverishly on a grant and some manuscript revisions. Which I now feel the need to procrastinate on.But, it's a bit intimidating to jump back in, after being completely off the blogosphere radar for so long. So, I'm going to take this post as an opportunity to warm back up and, sometime this weekend, I promise to post on some nice 'n juicy hormones/behaviors bits that I've had on my (very far) back burner for far too long now...But, because I'm a sucker for a meme, I give you my belated Meme of Four:4 jobs you've had:1. Catering staff at a winery2. Barista at an independent coffee/art house3. Babysitter extraordinare, currently to a 18mo toddler that calls me Cake4. Does graduate work count as a job?4 movies you could watch over & over:1. the Godfather Series2. Little Miss Sunshine3. Love Actually4. Center Stage (shamefully)4 places you've lived:1. Washington (state)2. California3. Florence, Italy4. New Jersey (follows the Renaissance perfectly, doesn't it)4 TV shows you love to watch:Disclaimer: I haven't really watched TV for over 10yrs. I will only watch "Man versus Wild" because I'm infatuated with Bear Grylls. So I've changed the topic to:4 authors you love to read:1. Tom Robbins2. Milan Kundera3. Pablo Neruda4. Roald Dahl4 places you've been on holiday:1. Costa Rica2. China3. Chile (in a month!)4. San Francisco (most recently)4 websites you visit daily:1. Facebook2. Gmail3. Science Communication Consortium4. scienceblogs.com4 of your favorite foods:1. Peaches2. Avocados3. Homemade bread4. Pumpkin pie!4 places you'd rather be:1. on the waterfront2. in the MOMA3. on a nice long run4. on a massage table4 lucky people to tag:No tagging today - I'm turning the questions back to whoever generously still has me on their RSS. Lovely readers, pick one of the topics & give me a unique answer - I want to know a little bit more about who's out there!Idle threat: if you don't answer, I'll be forced to conclude that everyone has given up on me as an (understandable) result of my inconsistent posting and will shut down the AC for all of eternity. So there. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=1044157 Wed, 21 Nov 2007 17:06:00 +0100 1044157 http://anteriorcommissure.blogspot.com/2007/10/reproductive-rights-of-pigeons.html I write a lot about mating, partner preference, attraction...all the things that factor into reproduction. But on the train ride into lab this morning, I spotted THIS:NYC official suggests birth control for pigeonsNEW YORK - A city official is suggesting birth control for dirty birds that congregate around the Staten Island Ferry terminal....City Councilman James Oddo says contraception may help to reduce the proliferation of pigeons at the St. George terminal on Staten IslandWhat will they think of next.According to the available info on this so-called bird birth-control, Ovocontrol P (manufactured by Innolytics), a substance called nicarbazin interferes with the development of the vitelline membrane that surrounds the egg yolk. The vitelline membrane is covered by protein receptors, which help sperm bind to the yolk, initiate a number of complex intra-yolk mechanisms to 'activate' the egg, and, eventually, start the process of early embryonic development. By interfering with this membrane, the "hatchability" of the pigeon's eggs is disrupted.To be fair, not many people adore pigeons. Especially in NYC. In my undergraduate lab, I worked with beautiful White Carneau pigeons. I felt like they were always misrepresented, misunderstood. I changed my mind as soon as I moved to NYC. They're EVERYWHERE.*As city councilman James Oddo said:“My concern is the thousands of Staten Islanders who have a tortured commute that is made even more challenging by winged animals. The reproductive rights of pigeons comes in a distant second to my constituents and their commute.” [emphasis mine] Fair enough, fair enough.So long as the reproductive and general health of the pigeons is preserved (EPA classifies nicarbazin as non-toxic), this seems like a potentially viable solution. Apparently Philadelphia's already considered it. But the concept still tickles me.* Important note: this does not mean that I enjoy the fact that people put those pokey things on top of lampposts that hurt the pigeon's feet so that every other pigeon you see is walking around with a missing little pigeon-toe or a clubbed foot. Poor little guys. image (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=995105 Wed, 31 Oct 2007 14:02:00 +0100 995105 http://anteriorcommissure.blogspot.com/2007/10/acquired-maternal-behavior-story-of.html Every year before our annual neuroscience conference, my program holds a day-long minisymposium where we share our research and give feedback to others, host a keynote speaker, and (in true grad student spirit) stay up late finishing off all of the alcohol from the concluding reception. This year, a lot of people seemed intrigued in a unique little model that I used in a recent study on maternal behavior, which delighted me as I think that the model provides fascinating insight into the maternal state and the interaction between hormones and experience on the parentally responsive mammal.So, here's a post in tribute to this little model.First, let's set the stage... Most rodent researchers know that virgin female and male rats will typically avoid, attack, or bury young offspring (pups) if presented with pups in their homecage. While these young pink things might seem cute and helpless to the parentally responsive female (i.e. immediately after giving birth) or to a sappy grad student (i.e. me), they emit ultrasonic vocalizations, root for the female's nipples almost constantly and thus provide novel somatosensory stimulation to the female's ventral surface, and are associated with unique olfactory stimuli (odors). All of these attributes are extremely novel to the virgin female and male rat, who, aside from their own infancy, have probably never been exposed to young offspring or their associated stimuli. So, as these stimuli are novel, and as survival is often contingent upon an animal's safety and thus avoidance of novel, unknown stimuli, it is only logical that virgin females and males avoid pups. That is, cower in the corner when presented with this tiny pink thing.But once a female gives birth, the neural circuitry supporting this avoidance of pups (notably, olfactory input to the medial amygdala) switches off. Once that switch is flipped, the female becomes interested in approaching and interacting with her pups. At this point, pup odors actually encourage the female to lick and groom her pups (as do pups' vocalizations) and to prefer spending time with pups in her nest. Now, a whole new neural circuitry has turned on, supporting active parental, caregiving behavior in the newly-maternal rat mother.As you might guess, the hormones of pregnancy and birth play a large role in promoting maternal responsivity. Small mammals rely more heavily upon hormones to govern sexual and parental behavior than do large mammals, and maternal behavior in female rats is no exception.The question becomes: does the female actually NEED to experience pregnancy and/or give birth to behave maternally?The answer is, not exactly.It turns out that, if a virgin female is exposed to pups constantly over a period of days, she will start behaving maternally toward them. She will build a maternal nest, retrieve pups back to her nest, and crouch over them as if nursing them despite the fact that she's not lactating and therefore unable to feed them. Even more intriguingly, it can happen in male rats, too. To me, the behavioral flexibility supporting this "acquired caretaking role" is just fantastically amazing.So, there's your scientific evidence that virgin animals (male or female) don't need to experience pregnancy and birth in order to behave parentally. This makes innate sense to us humans - men don't experience pregnancy and birth, yet are strongly and immediately paternal toward their child. So are adoptive parents and foster parents.But given the relatively tight hormonal regulation of parental behavior in small mammals, the ability to induce maternal behavior in otherwise-unresponsive, nonparental females and males is absolutely striking. In female rats, it provides a unique little model in which to study the effect of postpartum hormones on parental care, without possible intervening influences of pregnancy, birth, and lactation.But more important implications might be afoot. Prolonged exposure to offspring is sufficient to facilitate solid parental care in rats and other small mammals, which seems extremely adaptive to species survival. In a way, induced parental care reflects a form of alloparental behavior (caregiving behavior performed by non-parent members of the community), in that they seem to provide similar benefits to the community - parents can go off to forage for food, mate, sleep, etc, while somebody else stays home to watch the kids. Yet in a natural setting, virgin female and male rats aren't exposed to pups for prolonged periods of time and thus don't express parental behavior. So...why? Seems that it'd be advantageous, doesn't it.Neat model, right?image (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=991992 Tue, 30 Oct 2007 14:27:00 +0100 991992 http://anteriorcommissure.blogspot.com/2007/10/im-ba-aack.html I'm back from blog-vacation!While I imagine that everyone has had a lovely week of engaging science chatter in the blogosphere, I was actually a tad relieved to take a break and concentrate on my talk. But now that it's over, I'm looking forward to jumping back into the middle of things, and hoping to slot in a few solid posts before I'm off to SfN on Saturday.In short, my thesis proposal talk went swimmingly. Beforehand, I was a bit of a...hmm, shall we say...over-caffeinated nervous wreck? Which naturally made me dismiss our wonderful postdoc's recommendation to "make it as fun as possible" with an eyeroll and a thanks. But as soon as I launched into the talk, it was fun. Really fun. And everyone not only followed my talk but asked really insightful questions afterward, which delighted me to no end.So, with that tiny milestone under my belt, I'm officially ABD. And back to my normal self. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=987242 Mon, 29 Oct 2007 13:59:00 +0100 987242 http://anteriorcommissure.blogspot.com/2007/10/scientists-night-with-media.html I am so exhausted.In the midst of working on my proposal talk, my two SCC colleagues and I held our second evening lecture on how specific media outlets report scientific research and interact with scientists. I was thrilled to host each of our panelists, help moderate the ensuing discussion, and listen to some insightful questions asked by our audience.We'll post our notes from the lecture on the SCC website soon. Until then, Brian (who I finally had the pleasure of meeting in person and who I'll be sitting on a panel with in January) provides a nice summary and some reflections. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=964739 Fri, 19 Oct 2007 20:16:00 +0100 964739 http://anteriorcommissure.blogspot.com/2007/10/intellectual-for-day.html How flattering! The AC was besowed with an Intellectual Blogger Award from Laelaps:This award is intended for those bloggers who demonstrate an inclination to think on their own. This is what I think is needed in today’s blogosphere. The term ‘Intellectual’ has often been derided in recent times, and this is one way to resurrect the true meaning: “An intellectual is one who tries to use his or her intellect to work, study, reflect, speculate on, or ask and answer questions with regard to a variety of different ideas.”Funnily enough, when I first started posting, I never intended to make my blog public. I wanted to use it as a space to store my scientific reflections and as inspiration to spend a bit more time thinking about a handful of the stacks of interesting papers that I come across. So it's quite an honor that my writing is even noticed, much less appreciated, and I'm absolutely delighted that others get a thing or two out of it.I can now nominate other bloggers who I consider "intellectual" so here are my two picks:Neurophilosophy - I found this blog relatively recently, when the blogosphere was abuzz with his mind-boggling post on the history of trepanation. His writing is consistently thorough, thought-provoking, and with refreshing perspective. I believe I told him something to this effect at 1am outside a bar in the East Village; hopefully, the award has a bit more meaning.Female Science Professor - Her posts consistently contain an incredible amount of insight, humor, and pathos regarding the trials and tribulations of being a female academic in a largely male-dominated field. She serves as an outstanding reminder of the thoughtful consideration that goes into leading a well-balanced and equitable life as a professional woman, and represents modern feminism beautifully. She's also an outstanding writer. I neglect her blog more than I should, as each time I revisit it, there's a slew of lovely and insightful new posts.I'd nominate Laelaps himself, but you sadly cannot nominate someone who has already won. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=959847 Thu, 18 Oct 2007 01:09:00 +0100 959847 http://anteriorcommissure.blogspot.com/2007/10/gestational-oxytocin-predicts-future.html I just...can't...stay...away...So just yesterday I resigned myself to not posting until my thesis proposal talk was over (next Friday). But this is really more of a half-post to lead you to a really fascinating-sounding study. Fascinating-sounding because I have a few questions and desperately need to read the actual study, once it's out:Initial levels of oxytocin at the first trimester predicted bonding behavior. Therefore, mothers with a high level of the hormone at the beginning of the pregnancy engaged in more of the aforementioned bonding behaviors after birth. Additionally, mothers who had higher levels of oxytocin across the pregnancy and the postpartum month also reported more behaviors that support the formation of an exclusive relationship... These mothers were also more preoccupied by thoughts of checking on the infant, the infant’s safety when they are not around, and the infant’s future.This study, which appears in the November issue of Psychological Science...suggests that women with higher levels of oxytocin during their first trimester are primed to the formation of an exclusive bond with their infants. Oxytocin seems to be preparing mothers to engage in bonding behaviors. Fascinating!This all follows the same vein of Feldman's work; a similar study was released earlier this year:Oxytocin (OT), a nanopeptide hormone, plays a role in the emergence of maternal behavior, yet few studies examined OT in humans across pregnancy and the postpartum. We followed healthy women at three points: first trimester of pregnancy, third trimester, and first postpartum month. Plasma OT levels showed high individual stability. A third of the sample showed consistent OT levels, whereas others showed increasing or decreasing trends or peak in late pregnancy. The ncrease in OT from early to late pregnancy correlated with higher maternal-fetal bonding. These data may help set standards for OT levels and underscore links with maternal-infant attachment.It kills me not to write more, but my thesis calls... So, sally forth and read this good stuff.(hat-tip) (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=957407 Wed, 17 Oct 2007 13:42:00 +0100 957407 http://anteriorcommissure.blogspot.com/2007/10/proposal-lamentation-and.html So, in the past two days, pre-proposal panic has set in. (Apparently, alliterations are also abound). Though it's still a full ten days away, I finished a rough version of my talk last Friday evening and have holed myself away to catch up on literature that 1. I've forgotten about because I have a terrible memory for what I've read, and 2. I'd never gotten to read in the first place and am now attempting to use to putty the important little holes in my knowledge before my talk. I'm continually teased by my friends/family/strangers that I'm entirely overprepared for these types of things and that I shouldn't worry so much, which makes me believe that I might have some sort of low-grade anxiety problem. But hey, everyone has their "thing," right? Mine is just the mild-to-moderate schedule-induced distress you see in unnecessarily Type-A graduate students. Totally normal. (?)So after today, I'm imposing a blogging-ban on myself for the rest of the week. It'll be difficult, and I'll miss you all, but it must be done. My sanity is on the line.Uh, starting after this post, of course.So, I was clued into a writeup on research examining the trade-off between mating and parenting in male Carolina dark-eyed juncos. It's a nice solid little paper recently published in The American Naturalist.I can't do the number on it that I'd like to, but here's the gist. The general rule of thumb in the animal (and, more specifically, mammalian) kingdom is that the care and protection of offspring typically falls into the hands (paws) of the female of the species. Female mammals are the only sex capable of lactation and are obviously present at birth, leaving them as the most natural parent to fill the role of caretaker. With increasingly higher orders of mammals (i.e. primates, humans), parenting behavior becomes increasingly detached from hormonal regulation, and fathers can assist in most aspects of childrearing. Many primate fathers spend a significant amount of time carrying infants and gain a substantial amount of weight around the birth of their children, which researchers assume helps to offset the energetic demands of infant caretaking.Like higher-order mammals, there are many documented cases of paternal and alloparental care in avian species - fathers will hang around the nest to watch the kids, non-parental community members will watch the kids. The range of roles that avian males might maintain is absolutely astounding, but whatever the strategy of each particular species, it is always presumed to benefit the survival of that species in the most optimal way.In the case of the juncos, however, researchers were curious whether the same species might share multiple strategies. Perhaps some individual birds would invest their energy in paternal behavior, they hypothesized, whereas other individual birds would abandon their mate and her nest in pursuit of other mating opportunities. Investment in both of these behaviors is neither advantageous nor practical, forcing males to assess the trade-offs of each behavior.As the authors write:Males that are more likely to succeed in obtaining mates because, for example, they possess a more attractive ornament, would benefit from increased investment in mating, whereas males that are less likely to be successful at mating may benefit more from investing in parental care. Selection may thus maintain variation in the resolution of this trade-off as well as its covariation with male attractiveness or quality.They discovered that natural fluctuations in testosterone, particularly over relatively brief spans of time, predicted whether the male was more likely to pursue mating opportunities or invest in caretaking behaviors at the nest. Reductions in testosterone have already been associated with paternal care in primates, so the fluctuations of testosterone reported in this study provide a solid but slightly expected contribution to the literature. But co-author Ketterson hit on the more intriguing key point, in my eyes, when she explained:[F]or a songbird living in the field under natural conditions...individual variation in the hormone testosterone maps onto variation in aggression and parental behavior...Our data also suggest that there is more than one way to be successful at reproduction. Some males may seek mates at the expense of parental behavior, but other males are doing the opposite. They are being more parental at the expense of aggression. And apparently both ways of being in the world work. [emphasis mine]That individual differences in hormonal levels support variations in behavior, each of which is individually adaptive based on each male's unique attributes (e.g. plumage, ornamentation), in such a readily apparent way is just fascinating to me. For some reason, it's strangely reassuring to see individual differences in non-human species as well; while we humans cling fiercely to our individuality, we often overlook intra-species variability as a simplistic and fundamental tenet shared by all of us in the animal kingdom. That's just lovely to be reminded of.image (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=956237 Tue, 16 Oct 2007 13:55:00 +0100 956237 http://anteriorcommissure.blogspot.com/2007/10/evolution-in-cyberspace-meme.html I was tagged yesterday by Bora. Memes can get a little out of control, but I found this one pretty intriguing.There are a set of questions below that are all of the form, "The best [subgenre] [medium] in [genre] is...". Copy the questions, and before answering them, you may modify them in a limited way, carrying out no more than two of these operations:* You can leave them exactly as is.* You can delete any one question.* You can mutate either the genre, medium, or subgenre of any one question. For instance, you could change "The best time travel novel in SF/Fantasy is..." to "The best time travel novel in Westerns is...", or "The best time travel movie in SF/Fantasy is...", or "The best romance novel in SF/Fantasy is...".* You can add a completely new question of your choice to the end of the list, as long as it is still in the form "The best [subgenre] [medium] in [genre] is...".* You must have at least one question in your set, or you've gone extinct, and you must be able to answer it yourself, or you're not viable.Then answer your possibly mutant set of questions. Please do include a link back to the blog you got them from, to simplify tracing the ancestry, and include these instructions.Finally, pass it along to any number of your fellow bloggers. Remember, though, your success as a Darwinian replicator is going to be measured by the propagation of your variants, which isgoing to be a function of both the interest your well-honed questions generate and the number of successful attempts at reproducing them.The best time travel novel in historical romance is: "Outlander" by Diana GabaldonThe best scary movie in sociopolitical dystopias is: Either 28 Days Later (directed by Danny Boyle) or Children of Men (directed by Alfonso Cuarón)The best sexy song in new jazz/blues is: "Teach Me Tonight" by Amy WinehouseThe best whimsical story in adult short stories is: "Skin" by Roald DahlAnd now for my lineage. My great-great-grandparent is Pharyngula. My great-grandparent is Metamagician and the Hellfire Club. My grandparent is Flying Trilobite. And my parent is Blog Around the Clock.I tag CerebralMum, Ed Yong, Brian of Clastic Detritus, and Brian of Laelaps... (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=950959 Mon, 15 Oct 2007 12:37:00 +0100 950959 http://anteriorcommissure.blogspot.com/2007/10/funny-ways-people-have-found-ac-via.html A lot of people stumble across the AC through Google searches. My site undoubtedly leads most of them far, far astray from their initial search aim. To commemorate my 200th post, I chose the more silly ones to share (anonymously, of course):no strings attached relationshipno strings attached sexunreceptive audiencewhat makes a face attractivegood looking womenwhat men like to hear during sexbaby face attractivelove researcherswhat makes men look for other womenacademics may be unfamiliar with gentlemenand last but not least, the non sequitur:ocean diorama junior highBased on this list, I'd guess that most people were probably searching for relationship advice or porn. Instead, they found a science blog. Ouch. Well, hopefully they learned something. If they stayed longer than two seconds.P.S. I found the penultimate search query hysterical, then realized that it was a quote from my lapdance post from Wednesday. Oops. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=947447 Fri, 12 Oct 2007 01:56:00 +0100 947447 http://anteriorcommissure.blogspot.com/2007/10/lap-dancers-take-note-of-your-cycle.html My good friend and colleague Katie sent this writeup of some newly published research that at first glance seems a bit bizarre but actually reveals some intriguing nuances:In a particularly stimulating study, researchers have found that lap dancers--women who work in strip joints and, for cash, gyrate in the laps of seated men--earn more when they are in the fertile phase of their menstrual cycle.Crazy! How could you not be intrigued by a study like that? I had to look it up.The actual research article correlated tip earnings with the menstrual cycle phase of female lap dancers recruited through emails, advertisements and flyers. While the sample size was small (n=18), data was collected from over 5300 lap dances. Researchers found that the women earned less money during menstruation and earned the most money during estrus (around ovulation). Women taking oral contraceptives, which induce a relatively stable hormonal state (i.e. pseudopregnancy), earned less tips than cycling women did.The study concludes that "when women and men interact intimately over the course of several minutes through conversation and body contact, women apparently either 'signal' or 'leak' cues of their fertility status, and these cues [may] influence spending patterns by male consumers." But could this be the whole story?It's certainly true that primate mating and reproduction is generally less dependent upon hormones than it is in smaller mammals (see my earlier post). While the fluctuation of ovarian hormones across a primate's reproductive cycle may contribute to attractivity and proceptivity (e.g. solicitations for contact), most primates are not only capable of mating during non-fertile periods but do so frequently. This hormonal "emancipation" has led researchers to suggest that hormones may affect the motivation, but not the physical capacity, to mate, both in non-human primates and in humans.Co-author K. Grammer also seems to attribute these differences to hormonal changes in the dancers themselves, suggesting that "estrogen [may] modulates motion abilities...[meaning that] body motion--and not pheromones--is the information carrier."I would tend to agree with Grammer's attribution of the cycle-tip effect to the female and not the male. In most small mammalian species and even some fish, pheromones emitted by the female help to clue males in to her reproductive status; however, much research suggests that it is unlikely that pheromonal cues play the same role in human males.But my female-based hypothesis would also incorporate findings from this study:Ovulatory shifts in human female ornamentation: near ovulation, women dress to impressHumans differ from many other primates in the apparent absence of obvious advertisements of fertility within the ovulatory cycle. However, recent studies demonstrate increases in women's sexual motivation near ovulation, raising the question of whether human ovulation could be marked by observable changes in overt behavior... [W]e show that readily-observable behaviors - self-grooming and ornamentation through attractive choice of dress - increase during the fertile phase of the ovulatory cycle. At above-chance levels, 42 judges selected photographs of women in their fertile (59.5%) rather than luteal phase (40.5%) as "trying to look more attractive." Moreover, the closer women were to ovulation when photographed in the fertile window, the more frequently their fertile photograph was chosen. Although an emerging literature indicates a variety of changes in women across the cycle, the ornamentation effect is striking in both its magnitude and its status as an overt behavioral difference that can be easily observed by others. Could it be that these females (albeit, uh, provocatively dressed during all dances) were dressed any differently or made themselves up more for the dances performed around estrus, without realizing it? Paired with Grammer's suggestion that estrus may be associated with improved coordination (estrogen has been directly linked to increased locomotor activity, both baseline and drug-induced, in smaller mammals), perhaps a good shot of estrogen is all it takes to set yourself apart as a highly tipped dancer a couple nights a month.Good thing that the research is now out there to prove it :)As an aside, the study's authors explained why lap dances provided an ideal setting for examining attractiveness via fertility cues by including a endearingly detailed description of gentlemen's clubs, as "academics may be unfamiliar with the gentlemen's club subculture." It's a humorous read.(Check out this Fun Study of the Day, which I stumbled across while researching the above) (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=943113 Thu, 11 Oct 2007 00:01:00 +0100 943113 http://anteriorcommissure.blogspot.com/2007/10/more-sci-comm-literacy-my-faith-in-non.html Some thoughts on yesterday's summary post of Sheila Jasanoff's reflections on science communication:Firstly, Sheila is right.The public is much more educated and interested in the specifics of science than we give them credit for. Perhaps not the specifics of protein misfolding, or the regulation of gene transcription, or the number of synaptic boutons on a dendritic spine head in the hippocampus. To be honest, while some specifics can be deliciously nitty-gritty to us scientists, others can be difficult for scientists to listen to, too. But the specifics of what scientists are researching, and why and how, seem to be much more intriguing to the lay public than most believe them to be.* So I think, and John Horgan seems to agree, that we scientists should put a little more faith in the non-scientific public.Certainly, there are people out there who are entirely disinterested in science. Which, really, is entirely acceptable - there are many fields that, despite my best efforts, I will never naturally warm to and I can't pretend (convincingly) to enjoy.** But on a personal note, either I have extremely supportive friends and family who enjoy chatting science, or I'm blind to their rolling eyes and exhausted sighs when talking about my research.*** Do I "frame" my research in a certain way, depending on my audience? Yes, just as most scientists do. I'm not disregarding framing as a necessary tool for developing an audience-specific soundbite to promote your research - that is the initial size of information able to be readily consumed by society, based on the constrictions of most current media outlets and much of the political system.But scientific literacy stems from much more than this initial info-bite. I have rarely had someone who, after I've spouted some sort of scientific semi-nonsense, hasn't asked me insightful questions and pushed to understand more about it. Whether a scientist or non-scientist, most people have an innate curiousity that drives us to understand our surroundings, who we are, how we work - all the major fundamental questions driving science itself. When kids are little, this curiosity is wonderfully unaffected, but as we age, we either grow more jaded, more insecure, more over-scheduled, more whatever that causes us to restrict that curiosity, securing it away with an airtight cap. So, to me, Jasanoff's argument on behalf of the Knowledge-Able Citizen rings true - society is composed of people very much capable of knowledge, of curiousity, and of understanding. And, if many of those are willing to engage with science, given the opportunity and the time, it seems that the most effective way to communicate science is by nurturing that curiosity, encouraging critical scientific thinking, and engaging the public more deeply in thought-provoking, challenging issues. The seeds of it are already there.This probably sounds overly optimistic, even unrealistic. Perhaps these people that I'm talking about, spread across the country as they are, aren't as randomly distributed as I think, possibly composing a more similar and science-interested demographic. But I'm holding out faith.But the only meaningful way that science can reach out to non-scientists, in the most forward-thinking, future-based way, is by championing the characteristics of Jasanoff's Knowledge-Able Citizen. Setting aside those who are entirely disinterested in science, which I'd argue is a smaller proportion of the population than many seem to believe, I don't think that scientists can justifiedly neglect the intellectual needs of the much larger, knowledge-able public.* example: i was recently criticized for blowing an inaccurate title of a science piece out of proportion (some of which was on the principle of the thing); just last weekend, an anonymous non-scientist reader told me that, had she just seen the title, she would have come away with a much different idea of the science and that she enjoyed reading my explanation/justification. her comment dovetailed nicely w/ jasanoff's point and motivated me to finally post this.** e.g. the stock market ***this is not entirely rhetorical and, in fact, a very real possibility. i wouldn't flatter myself that much. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=938870 Tue, 09 Oct 2007 13:56:00 +0100 938870 http://anteriorcommissure.blogspot.com/2007/10/jasanoff-on-science-communication.html I recorded some notes at Dr. Sheila Jasanoff's lecture for SCC, given on Thursday, September 27th, 2007 at Columbia University. As no audio recording of the lecture was made, these notes represent my paraphrased summary of Dr. Jasanoff's lecture. While I believe that my notes faithfully reflect her theoretical points, Dr. Jasanoff is in no way liable for any of the below phrasing or, most importantly, the representation of her ideas. Any and all mistakes in phrasing, semantics, and/or misconstrued theory are attributable to me. We at SCC intend only to convey the gist of the lecture for your thoughtful reflection and scholarly consideration, and therefore ask that these notes be referenced globally instead of quoted.Cross-posted at SCC.Dr. Sheila Jasanoff introduced the topic of science communication as one of intimidating breadth and scope, inviting her audience to “think with” her as she began an intellectual journey through some of the major components of science communication. She stated that the current “conventional American approach” to science communication isn’t effective and called for us to reorganize our lives in order to continue thinking deeply about the issues surrounding the current state of communication in science and technology. First, Jasanoff stated that scientists aren’t doing most of the communicating about science, citing Colin Powell’s political discussion of nuclear technology and many instances of ineffective or dishonest representation of science under the current administration. However, Jasanoff argued, openness and communication about science is not the norm in our society. While the peer review process is heralded by both scientists and non-scientists alike as a transparent means of discussing, analyzing, and synthesizing science, it is not representative of how science is typically discussed, analyzed, or synthesized by the rest of the population. Jasanoff reminded her audience that communication does not occur within a vacuum but to an audience, and each audience is associated with a certain degree of openness or receptivity. Thus, the pertinent key issues encompass complexities related to: what is science communication, by whom is science being communicated, to whom is science being communicated, and for what purposes is science being communicated. Jasanoff proposed that two cultures of science communication exist in modern democracies. The first culture, dubbed the public service model, focuses on the individual role of the scientist, who has a responsibility to communicate the larger impacts of his/her work (e.g. National Science Foundation’s requisite “Broader Impacts” statement in competitive grant applications); as the success of this model is highly dependent upon individual scientists’ integrity, virtues, and personal value system, Jasanoff referred to this model as promoting “boy scout ethics,” in which scientists serve as well-intentioned, active participants in society. Jasanoff cited the UK’s Ethical Code of Science (2006), proposed by Professor Sir David King, as an example of a formalized code promoting professional integrity, rigor, and social conscience amongst scientists and encouraging individual researchers to consider the larger impacts of their work.The second culture, the public sphere model, focuses on the social purposes of science communication. As scientific debate is an essential component of a democratic society, both scientists and non-scientists (e.g. politicians) have a pressing responsibility to engage all members of a society in the discussion of scientific matters. Delegations composed of scientists and lay people should be accountable for ensuring the inclusiveness of discussion. Jasanoff argued that reliance upon “boy scout ethics” in ensuring effective science communication is unrealistic due to the fundamental nature of how science is conducted. Competition between individual laboratories and between larger institutions, commercial confidentiality, patent races, and party politics (i.e. if science serves the public good, party politics often defines the nature of that public good) are all fostered by scientific discovery. So, despite Sir Richard Southwood’s warning that the “evasion of providing [well-reasoned scientific] guidance is a dereliction of one’s duty as a scientist to society,” the “boy scout” model proves insufficient for ensuring effective and timely communication regarding scientific matters. Jasanoff also proposed that C.P. Snow’s distinction between sciences and humanities as separate ‘cultures’ in society may not fairly represent modern democracies. Instead, Jasanoff argued, the conventional wisdom that the non-scientific public is largely technically illiterate, poorly informed on scientific fact, and/or incapable of basic scientific thinking is inaccurate. Citing the National Science Foundation (NSF)’s Indicators in Science & Technology Public Attitudes and Public Understanding (detailed in the infamous “Chapter Seven” of NSF’s encompassing report on scientific research priorities, funding, competitiveness, societal roles, and public perception) as a highly visible example, Jasanoff argued that Americans have a persistent belief that the knowledge of an arbitrary set of scientific facts constitutes a sort of scientific intelligence and acts a point of comparison to scientific literacy and educational systems of other countries (and from which Americans glean a strange source of pride). However, this arbitrary knowledge does not meaningfully represent scientific literacy, which instead encompasses aspects of critical thinking, analysis and synthesis, and a capability and competency to deal with new knowledge. Based on this distinction, Jasanoff proposed the model of the Knowledge-Able Citizen. This Citizen has a right to citizenship in a knowledge-able and knowledge-seeking society, which includes freedom of the press and of information, transparent decision-making and advisory processes, right to knowledge (r.e. risk exposure, consumption of food/drug products, etc), right to demand justified reasons, right to offer expertise, and right to challenge irrational decisions. Jasanoff argued that these conditions are inherent to citizenship in American democracy and, while not adhered to perfectly, fosters citizens that differ drastically from the perceived citizen lacking the capacity for scientific thinking and lacking the ability to develop technical expertise. Perhaps, she proposed, American society has been erroneously infantilized and non-scientists are entirely capable of critical thinking and synthesis of science, much more than most of society (including but not limited to scientists) gives them credit for. The outstanding problem, therefore, seems to be that scientific competence and literacy can be packaged for convenient or audience-specific communication but that the larger issues supporting science communication – including issues of by whom, to whom, and for what purposes is science communicated – are increasingly value-laden. Modern democracies must supply their citizens with the right to challenge, refute, and contextualize scientific data, and that right necessitates a deeper comprehension of science than society (including scientists, media, and policymakers) currently allows. Society loses faith in scientific expertise if science is not communicated effectively, honestly, and thoroughly. Many people believe that, if you can “break through” to the non-scientific public, the public will regain its trust in science. But perhaps, Jasanoff proposed, trust in science can be promoted through skepticism: while distrust rooted in closemindedness is detrimental, informed distrust is necessary to promote true democracy and nurture the public’s faith in science. Thus, perhaps the issue is not how we package science, but how we engage the public to think critically about the science. While packaging can be done carefully and with reference to specific audiences, Jasanoff maintained that packaging fails to energize the ideals of the public, which would represent the most forward-thinking approach, and thus may represent apathy or acquiescence. Only after conveying the deeper importance of science will the public lend its energy and support to the scientific enterprise, as, in Jasanoff’s words, “all human-created work is worth reflecting on.” Only by thoroughly engaging a democratic public over scientific issues can science and technology play its most vital role in bettering the human condition. This engagement will require answerable innovation from scientists, accountable expertise from administrators and officials, and active engagement and knowledge-seeking from the public. Only with the combined support of these constituent components can scientific and technological issues be reflected on with the appropriate scope and with due reference to the multi-fold impacts of these fields in society. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=935382 Mon, 08 Oct 2007 15:20:00 +0100 935382 http://anteriorcommissure.blogspot.com/2007/10/missing-in-scientific-action.html I'm home in Seattle on a long-awaited weekend with my parents. And to renew my expired driver's license. Happily, I've already heard an astounding battery of new, semi-bizarre stories tangentially related to hormones, once people (e.g. dental hygienist) learn a bit about my research. People typically share their (or others') personal hormone-related stories with reckless abandon, but I'm always a little more intrigued by (and, alright, comfortable hearing about) animal/pet stories than "the other day, you wouldn't believe how much I was lactating" stories from people I barely know. Today, I heard a good one about a pet bird's ovarian tumor that, when treated with some sort of estrogen analogue, caused the aged bird to start laying eggs. Huh.Anyway, all of this is intended to apologize for being M.I.A.I've been saving up a few interesting topics for upcoming posts, which I'll get to when I return to the blogosphere. Soon.In other news, I'm tickled to see that the AC has been nominated for the best new science blog over at Science in Review, following closely on the heels of another recent nomination in a much too competitive field. I"d recommend going to both sites to check out the other nominees, as there are some really brilliant minds that post frequently on really good, juicy science... (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=928950 Fri, 05 Oct 2007 01:11:00 +0100 928950 http://anteriorcommissure.blogspot.com/2007/09/smell-of-men.html Genetic variation in a human odorant receptor alters odour perceptionAndreas Keller, Hanyi Zhuang, Qiuyi Chi, Leslie B. Vosshall & Hiroaki MatsunamiFrom the abstract:Human olfactory perception differs enormously between individuals, with large reported perceptual variations in the intensity and pleasantness of a given odour. For instance, androstenone...an odorous steroid derived from testosterone, is variously perceived by different individuals as offensive ("sweaty, urinous"), pleasant ("sweet, floral") or odourless. Similar variation in odour perception has been observed for several other odours. The mechanistic basis of variation in odour perception between individuals is unknown. We investigated whether genetic variation in human odorant receptor genes accounts in part for variation in odour perception between individuals. [emphasis mine]So, could a receptor for odorants be selectively activated by certain smells? According to the OR7D4 receptor, yes. In fact, people with a certain variant of this receptor (OR7D4 WM) were less likely to rank the smell of androstenone as "sickening" (!) and much more likely to rank it as pleasant than people with the other variant (OR7D4 RT). These differential rankings of "valence," or pleasantness of the smell, appeared to be unique to androstenone and androstadienone, as similar differences did not emerge to 60+ other odors:The overly-tiny figure displaying valence rankings is only intended to provide an idea of the huge range of odors tested; the two yellow bars represent androstenone and androstadienone, the only two odors that were ranked as having significantly different valence based on OR7D4 receptor variant. See Figure 4a in the actual paper for details.Authors concluded that the genotypic variation in OR7D4 is a major predictor of the reported valence (pleasantness) of the specific smell of androstenone and androstadienone. As co-author A. Keller stated, "I find it most exciting about the study---that it explains how the world is perceived is subjective between different people and that there is actually a reason for that."What's particularly intriguing about this research, however, is the nature of the odorant tested - a derivative of testosterone. As far as I could tell, from the supplimentary figures, the differences in reported valence were consistent in both men and women, so implications for sexual attraction are enticing but perhaps a bit hazy.Nevertheless, a writeup at ScienCentral News tells a funny story:Androstenone is well known in the pig farming industry. It is a sex hormonefound in the saliva of male pigs. The smell of it causes female pigs in heat toassume mating position....[Says Keller] "We got an email from a woman who told us a story that she has a female pet pig and that one day the pig was in heat and it disappeared. And she went searching for it and found it among a group of sweaty construction workers at a nearby house and she told us that she thinks it's the androstenone odor of these men that attracted her pig." (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=912159 Fri, 28 Sep 2007 13:28:00 +0100 912159 http://anteriorcommissure.blogspot.com/2007/09/mother-tiger-seeks-cubs-for-comfort.html From one of those ubiquitous emails that has now-unknown origins but is heartwarming enough to continue circulating from inbox to inbox:The purported explanation goes like this: a tiger mother gave birth to cubs that died soon after birth,and she quickly became melancholic, slipping into some form of postpartum tiger-depression. So, the zoo dressed piglets up as tiger cubs and let the maternally responsive female care for them. I thought, How fascinating! Maternal instincts transcend species-specific barriers in the most unlikely ways!Sadly, the story is a bit misleading. The pictures were taken in 2004 at Thailand's Sriracha Tiger Zoo, where these "foster piglets" replaced her normal cubs solely for the purpose of "visual entertainment provided by the zoo for the amusement of visitors." Not quite so charming, anymore.But, would this even be possible with a non-maternal female or male tiger? I have no idea... (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=908753 Thu, 27 Sep 2007 19:41:00 +0100 908753 http://anteriorcommissure.blogspot.com/2007/09/animal-meme.html I've been tagged by Brian...An interesting animal I hadAs most of my friends are well-aware (and never let me live down), I've had a series of pets with really uninventive names. I adopted my second grade class' pet gerbil and named him Gerbie. He died a few months later and I erected a little cross for him in my backyard, then got incredibly concerned after my family moved that someone would dig him up. Soon after, my family took in a stray cat when I was in third grade, which I coaxed into our house on the way home from school by letting it drink milk out of the little cup attached to my lunchbox thermos. Thought we tested out more inventive names, Kitty was what stuck. A few years back, my parents recently got two new cats to replace the late Kitty, and as nobody could pull it together enough to remember a new cat name, the two new additions promptly became Little Kitty and Big Kitty. Pathetic, I know.Before any of these pets, I do remember desperately collecting sowbugs (we called them rolly pollies) from rotting logs in our backyard before Bring Your Pet to School Day. That must have been early in second grade, before Gerbie came along.An interesting animal I ateIn true Bear Grylls fashion, I ate scorpion-on-a-stick in the back alleys of Beijing. Squid-on-a-stick, too. Wouldn't recommend either.An interesting animal in the MuseumI adore the American Museum of Natural History in NYC. Their recently opened exhibit, the Hall of Human Origins, is absolutely fascinating and I'd strongly recommend cruising around their website if you can't make it to the exhibit itself. I also love their Oceans Hall - ocean life intrigues me immensely (what can I say, my mom sent me to marine biology camp as a kid). I particularly like the diorama depicting the tussle between the giant squid and sperm whale, as you don't often get glimpses of animals that live at those incredible depths, nevermind their behavior. It takes a bit of imagination, but there's something about that particular diorama that sparks my curiosity more than all the others.An interesting thing I did with or to an animalFor a while in junior high, I was really into horses, taking dressage lessons at one stable while volunteering with special-needs children at another riding stable. When my instructor wanted me to start jumping, I quit my lessons - it was scary enough cantering around the arena on my ready-to-run little mare.An interesting animal in its natural habitatLast winter, I took a two-week trip around Costa Rica. One of the most beautiful beaches that I've ever seen was in the Manuel Antonio National Park. Even though the water was perfectly clear, something stung me when I was wading around. It was incredibly painful and left patchy red welts on my right foot that lasted for six months and is still lightly visible. I never figured out what it was, as the welts didn't look like previous jellyfish stings, puntures that you might expect from an urchin, or a contiguous laceration from a sort of skate (???). A park ranger said it might have been something called ____ de oro. If you know what he might be referring to, let me know so that I can solve the mini-mystery about the identity of my little aquatic friend.I tag Ed Yong, Pondering, and Thomas!Feel free to add your own animal stories as comments...everyone has some good ones.image (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=908754 Thu, 27 Sep 2007 14:42:00 +0100 908754 http://anteriorcommissure.blogspot.com/2007/09/oxytocin-vasopressin-and-no-strings.html I should realize that articles entitled "The biggest sex mistakes men and women make" posted on MSNBC's TODAY section on "Relationships" (and sent to me by a friend, thank you very much) will probably make my eyes roll. It's not a site that you'd expect to present scientific research particularly accurately, as it serves its own non-scientific, pop-culture purposes. Fine - I can accept that.But when I saw #4 on their list of Biggest Mistakes, my eyes did not roll. No, no. Instead, I almost sent my computer monitor crashing through the window:4. Women don’t understand how men can differentiate so easily between love and sex.Ian: One of the reasons is that during sex, women produce lots of oxytocin, a hormone that stimulates a strong emotional connection. As a result, women are more emotionally integrated when it comes to sex. That’s why casual sex and hookups often backfire for lots of women. Guys produce little to no oxytocin, and can easily have sex without any sense of emotional connection. It’s sex with no emotional strings attached.Ugh. In fact, double-ugh.Curious, I found that "Ian" was Dr. Ian Kerner, clinical sexologist and sex therapist who has authored a number of books (including She Comes First and He Comes Next) on everything from "the nature of...desire to sex-techniques that work." This work earned him interview rights, which is just dandy. If it was clear what he was talking about.So, here are two issues that immediately popped into mind:First, while oxytocin function may be less associated with males than with females, males DO have it. It's unclear whether Kerner is arguing that males produce little to no oxytocin at their baseline state or during sex. If it's the former, it's untrue - males certainly do produce oxytocin and have oxytocin-responsive receptors in both periphery and brain. To option number two, recent evidence suggests that mesolimbic dopaminergic neurons may modulate oxytocin release in the ventral tegmental area (VTA), which together promote penile erection and potentially (as argued by the authors) the rewarding aspects of sex. While this particular link between reward and oxytocin remains tentative but intriguing, the role of oxytocin in the physical aspects of sexual function is fairly well-established. Which leads me to think that oxytocin is most definitely released in males during sex.My second issue is related to whether oxytocin participates in emotionality and bonding equally in males and females. While I'm very unfamiliar with the related literature on humans (please feel free to chip in), animal work suggests that vasopressin, not oxytocin, plays a much more prominent role in males. Both oxytocin and vasopressin establish partner preferences in voles, potentially working in concert to do so, but their nearly identical structure (differing in just two of nine amino acids) allows them to bind, albeit with decreased affinity, to each others' receptors. So, when considered individually, vasopressin was found to be both necessary and sufficient for pair-bonding in monogamous voles; later, this role of vasopressin was explicitely defined as necessary for pair-bonding in males but not for pair-bonding in females.Now, whether pair-bonding in small rodent-like mammals is equivalent to some sort of diffuse emotional connectedness in humans is up to you...but it's the closest it comes in small-mammal literature. The neuroendocrinological substrates supporting many sexual behaviors in small mammals accord closely with those in humans, however, so perhaps it's irrelevant to talk about the relationship between oxytocin and emotional connectedness in males because we should be talking about oxytocin's cousin, vasopressin, instead.As an interesting, related aside:While poking around for the above papers, I stumbled across a relatively new study that suggests that oxytocin increases the amount of time that men spend looking at the eye region of neutral faces. Now, could this extend to the bedroom? Who knows if the link is causal (it likely isn't) but in my reproductive endocrinology course, we read a study (which I'll find) that, during sex, men look at women's faces more than women look at men's faces! A curious finding, but not if you think about the physiological "clues" to sexual satisfaction - researchers theorize that the amount of time spent looking at a woman's face might help determine how she is, er, "feeling." I'm certainly not proposing a causal connection between oxytocin and face-looking during sex, but the studies are both interesting, potentially interrelated bits of info that I thought were worth sharing... (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=908755 Wed, 26 Sep 2007 16:09:00 +0100 908755 http://anteriorcommissure.blogspot.com/2007/09/abstinence-only-plus-some.html Jake has a great post on the effectiveness of abstinence-only (and "plus") programs for adolescent sex education. Required reading of the day. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=903785 Tue, 25 Sep 2007 18:34:00 +0100 903785 http://anteriorcommissure.blogspot.com/2007/09/like-pigs-at-trough.html I can't seem to embed it, so check out this video of piglets nursing.At face value, it might seem a bit bland, but when you consider the extreme physiological changes necessary to support lactation, videos like this are awe-inspiring.A few notes on nursing:Lactation constitutes an extremely energetically costly period for the female. In female rodents, a normal-sized litter of 14 newborn pups weighs approximately 20% of the female’s body weight; after only two weeks, they will outweigh her. To meet these enormous energy demands, females become extremely hyperphagic until her litter is weaned – eating for two (or twenty) makes a good deal of sense, of course, as the amount of food consumed by a lactating females positively correlates with her litter’s size. But watch what you eat, Mom – the offspring of females given a “junk food” diet during pregnancy and lactation (i.e. foods high in fat, sugar, and salt) also developed a preference for these “junk foods”; early nutrition also impacts the offspring’s future stress responsivity and brain development. Interestingly, replacing a female’s weaned pups with young offspring substantially reduced the quality of her milk (but not her hyperphagia), indicating that a lactating female may only be capable of supporting the incredible energetic demands of lactation for a limited amount of time. Makes you appreciate that poor mother sow in the video a bit more, doesn’t it?Another intriguing vein of lactational research has revealed that most mammalian females exhibit substantially reduced anxiety levels during the postpartum period (i.e. when they are lactating), compared to their normal state. While this reduction is not attributable to nursing persay, it instead depends on the intense stimulation of the female’s ventral surface by rooting offspring (i.e. piglets in video). As females exposed to rooting offspring continue to display reduced anxiety following the removal of major sources of stress and parental hormones (adrenalectomy, hypophysectomy), one might wonder if similar reductions in anxiety would be revealed in parental males, in non-nursing (e.g. adoptive) mothers, or in alloparents.I’ll look into this, but my best guess might be yes…(Anyway, all lactational demands aside, this has the potential to be much more taxing and/or treacherous for a nursing mother sow...!)image (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=903786 Tue, 25 Sep 2007 14:49:00 +0100 903786 http://anteriorcommissure.blogspot.com/2007/09/pregnancy-weight-gain-its-boy.html A recent Fertility & Sterility study, using an enormous cohort of 220,000 Swedish women, set out to examine whether a woman's second prenancy has a higher probability of being a boy or a girl. Their findings?The sex ratio of the second pregnancy increased linearly with the amount of maternal weight change from the first to the second pregnancies, from 1.024 in women who lost more than 1 unit BMI to 1.080 in women who gained 3 or more units.I can't access the article and would love to read the full thing, so if anyone can get to the full pdf, please send it along.Does that paltry-seeming difference in boy:girl sex ratio weight actually represent a statistically significant, honest-to-goodness, real-life difference? And, since I'm no expert on body mass index, or BMI*, I decided to convert the BMI units to actual weight in lbs, gained or lost: for a 65-inch tall woman weighing 132lbs, a 3-unit increase would represent a weight gain of 18lbs and a 1-unit decrease a weight loss of a puny 6lbs. Perhaps, given those fairly reasonable weight fluctuations (I'll buy the gain more than the loss), the ratio difference is quite significant. Can anyone familiar with population studies give me some insight as to how big these ratio differences are, in real world terms?You can find the press release on the study here, where authors take care to note that "Weight gain before pregnancy carries significant risks to the mother and the baby, and should not be practiced to influence the odds of having a boy," and that women shouldn't try to intentionally gain/lose weight to affect the probability that they will have a boy/girl. Good call.* Brief soapbox moment: To me, BMI doesn't seem to be particularly representative of body mass composition. Scores designating "overweight" and above could be attributable to fat, sure, but they could also be attributable to muscle. But, while my heart goes out to lots of muscular people potentially disheartened by their misrepresentative obesity scores, lower BMI scores representative of little fat and little muscle may arguably more representative of actual body composition. Anyhow, I'm slightly off-topic so will step down from soapbox. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=900985 Tue, 25 Sep 2007 03:08:00 +0100 900985 http://anteriorcommissure.blogspot.com/2007/09/for-those-of-you-in-nyc-area.html Come on out to a keynote lecture by one of my absolute favorite scholars, Dr. Sheila Jasanoff of Harvard's Kennedy School, at Columbia University this Thursday at 7pm. Her insights into the complex relationships between science, technology, and society, with a particular focus on democratic citizenship, are astounding. If you've never heard her speak before, you're in for quite an evening.See the Science Communication Consortium (SCC) website for more details; you can register at NYAS or at Columbia on the day of the lecture. Hope to see you there! (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=894323 Mon, 24 Sep 2007 02:07:00 +0100 894323 http://anteriorcommissure.blogspot.com/2007/09/theory-on-motivation.html As my semi-regular readers know, many of my posts address some of the most common naturally motivated behaviors - the drive to reproduce, to care for offspring, and to eat and drink when hungry and thirsty - that can be incredibly strong in most mammalian species. Researchers believe that the mammalian brain is primed, or "set up," to respond to mates, to offspring, to food and water by activation of a sort of innate neural circuity that supports the motivational (or reward) value* of each of these stimuli at biologically relevant times. Most female rodents find offspring to be highly rewarding immediately after giving birth but not at other times. Animals find food more rewarding when they are hungry than when they are satiated. And so on.Part of the intrigue regarding how this neural circuitry attributes reward value to natural stimuli (food, sex) relates to how reward value may be attributed to pharmacological stimuli (e.g. abused drugs). It's highly unlikely that any species has evolved a neural system that is exclusively responsive to drugs of abuse. So, many researchers believe that the neural substrates involved in natural rewards may be similarly involved in pharmacological rewards, theorizing that drugs of abuse "hijack" the natural reward system. In extreme cases of drug use and abuse, researchers have argued that this "drug hijack" compromises the motivation to eat, sleep, and reproduce while increasing the motivation to continue consuming drugs, hinting that the reward system "shifts" from being responsive exclusively to natural stimuli to being responsive exclusively to drug stimuli.Yet there is some fascinating evidence to the contrary, which I rediscovered while reading last week. Carelli and colleagues recorded from nucleus accumbens neurons** while rats bar-pressed to receive either food, water, or infusions of cocaine. Some neurons responded exclusively before or after rats received food or water, but not when rats received cocaine. That these cells were typically responsive to both food and water suggests the existence of an innate motivational system that is responsive to many different natural stimuli but not necessarily to responsive to non-natural (drug) stimuli. Interesting, though perhaps expected.Here's the kicker: Carelli also identified cells that were exclusively responsive to cocaine. They were silent when rats received food or water but responded strongly when rats received cocaine. How fascinating! Had a drug-responsive substrate actually been revealed in the brain?Quite a bit of effort has been directed toward rectifying these results, and it's very possible that these "cocaine-specific cells" are in fact responsive to another naturally rewarding stimulus that wasn't examined in Carelli's study (e.g. sex). But one incredibly intriguing idea suggested by P.S. Grigson is worth serious consideration:Perhaps single cells in the nucleus accumbens (and possibly other structures as well) are like stem cells, so to speak, a clean slate waiting to 'imprint' upon (code for) any stimulus in the environment that might be deemed rewarding. [G]iven the range of stimuli that human beings and animals find rewarding, and the need for plasticity - i.e., the need for adjustment with changing requirements, availability of resources, and experiences...perhaps it is just this type of plasticity that is required to seek the range of rewards necessary for life, such as salt, calcium, potassium, amino acids, iron, sweets, food, water, warmth and a mate.Could it be that our brains are wired loosely enough, so to speak, to allow us the capacity to respond exclusively to different stimuli that we encounter and find valuable in life? Is this how the most general/common stimuli and the most esoteric/specific stimuli can acquire value to us? Perhaps such a mechanism would allow individual differences in our motivated behavior, helping to explain how each of us is driven by specific stimuli, specific experiences, specific aspects of our lives...but not others.An intriguing concept, and one that I thought was worth sharing. I'm not sure what to make of it, quite yet...* For the purpose of this post, I use reward and motivation interchangeably, to the ultimate frustration of the hard scientist in me who acknowledges (loudly, most times) that they are neither interchangeable nor synonymous in some basic senses. Senses which I will not be discussing here.** Sadly, I've also intentionally avoided discussing the evidence for and against a role for nucleus accumbens in determining the reward or hedonic value of stimuli, instead only asserting that multiple lines of evidence do indicate that nucleus accumbens plays an important role in motivated and goal-directed behaviors, directed at natural and pharmacological stimuli.(As an aside, I realize that I've been starting a frightening number of my recent posts with an apology for not posting more frequently. But I actually do have to limit my blog-relationship for the next month, in which I'll be proposing my final thesis research, receiving two papers back from review and attending to their red ink, and (in a recent burst of faltering time management) applying for a small grant. Wish me luck, and understand that I'll sadly be posting a tad bit more infrequently...) (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=891881 Fri, 21 Sep 2007 15:21:00 +0100 891881 http://anteriorcommissure.blogspot.com/2007/09/life-science-blogs.html This is incredibly belated, but Laelaps has an absolutely fascinating post on horse evolution.We're fellow nominees for best Life Science blog over at The Scientist, though he posts much more frequently than I do. And writes better.Go check it out and nominate your own favorite! (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=886421 Thu, 20 Sep 2007 14:06:00 +0100 886421 http://anteriorcommissure.blogspot.com/2007/09/ota.html Denialism posted (and Pharyngula reiterated) a cry for scientists to push Congress to reinstate the Office of Technology Assessment, the bipartisan advisory committee to the legislative branch that released a number of recommendations and publications before funding was withdrawn and OTA was closed down in 1995. Last year, I heard staunch science advocate Rep. Rush Holt (D-NJ) speak passionately about reinstating funding for OTA, but so far no dice.Since the closure of OTA, some have argued that the only major scientific advisory committee continuing to weigh heavily in Congressional legislation is the National Academy of Sciences, which is non-governmental.Tomorrow I'm headed to the Hill to speak to staffers about science policy. So, the reminder comes at a good time. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=882981 Tue, 18 Sep 2007 16:04:00 +0100 882981 http://anteriorcommissure.blogspot.com/2007/09/sorry-kids-theres-no-such-thing-as-love.html I was really frustrated when I read this piece and have been waiting to cool off a bit before posting.I found a Reuters piece on a new Viagra study before I found the actual research article. The title of the Reuters piece? "Viagra boosts feel-good 'love' hormone: study." Hmm. Sounded like someone's taken a good deal of artistic (scientific?) licensing with some research findings. I decided to investigate.Here's the gist of the actual article, before I launch into a tyrade on responsible scientific reporting:Scientists have understood the primary mechanism of Viagra's action for a while now - an enzyme called PDE5 blocks a little molecule called cGMP, which (among other things) mediates the relaxation of blood vessels. Enter Viagra: by blocking PDE5, Viagra disinhibits cGMP and allows much more vascular relaxation. This activity is most, um, "apparent" in the periphery of the body, and thus Viagra serves a nice function of alleviating erectile dysfunction.What hasn't been clearly understood is the effect of Viagra on the central nervous system, including the brain. Researchers isolated the posterior pituitary, which releases the neuroactive peptides oxytocin and vasopressin into the circulation, in an in vitro preparation.* As oxytocin has a well-described role in sexual arousal and south-of-the-border smooth muscle contractions (i.e. orgasm, parturition), researchers were curious whether Viagra would influence the release of oxytocin.As it turns out, Viagra does increase the release of oxytocin. Viagra also altered the electrophysiological properties of oxytocin-releasing neurons - it increased BK channel activity, known to promote Na+ channel recovery from inactivation, and increased the propogation of action potentials. In other words, Viagra helped oxytocin neurons transmit info more rapidly.Now, what could this mean?Prior research revealed that male sex organs contain oxytocin receptors, so a Viagra-induced increase in oxytocin could hypothetically affect male sexual function directly.Oxytocin also has a well-established role in the contractility of male and female sex organs, which continues to fit nicely with our physiological theme.But oxytocin is also implicated in social relationships, affilative behavior, pair bonding and partner preference, and monogamy in select mammalian species, and even mother-infant bonding. All of these findings suggest the intriguing possibility that Viagra may influence more than just sexual arousal. Could it be (gasp) love?The most immediate issue, of course, is how love is defined. In a 1998 review on oxytocin and sexual pleasure, love is operationally defined as "having one's having stimulation that one desires." Talk about encompassing both physiological and psychological/emotional interpretations - love could be just about anything!But researchers also remind us that "Animal models of reproductive behaviors, mother-infant attachment and pair bonding complemented by human studies reveal neuroendocrine foundations of prosocial behaviors and emotions." And, as Sue Carter wisely points out, "Parental behavior and sexual behavior, even in the absence of selective social behaviors, are associated with the concept of love" (emphasis mine). The key to correctly interpreting these findings is that cute little italicized phrase.Simply because Viagra is closely tied to sexual function and, via its recent association with oxytocin, social bonding and affiliative behavior does not mean that Viagra elicits love.Yet Reuters pipes up with this gem of an announcement: Viagra boosts feel-good 'love' hormone: studyI understand that science needs to sex itself up by better framing our research, that scientists need to improve how we communicate with the lay public, that scientific explanations are typically too gritty for most people to grasp and/or care about. Fine.But a title like that is misleading in the utmost sense. People will be using Viagra under false pretense. No, spiking someone's drink with Viagra will not make them fall in love with you. No, love is not a valid off-label use.The associated press release is preferrable: Study finds Viagra increases release of key reproductive hormone. That, I can handle. But it's notably less catchy, easy to remember, and novel. In other words, you'd have a conversation at the water cooler about the former but, unless you're me, not the latter.Am I the only one that gets frustrated with irresponsible reporting like this?* i.e. outside of the animal's body in a petri dish (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=880342 Tue, 18 Sep 2007 13:03:00 +0100 880342 http://anteriorcommissure.blogspot.com/2007/09/hug-hug-me-do.html Some intriguing research was just released in Animal Behaviour:Compared to most Old-World monkeys (e.g. chimps, gorillas), spider monkeys spend much less time grooming each other. But, researchers say, grooming is a desired activity - highly social events such as grooming increase the likelihood of infant survival amongst female baboons and may boost the release of the pleasurable opioid beta-endorphin. In fact, grooming has enough value that it can be exchanged for other biologically relevant opportunities (i.e. feeding, grooming, mating) in what is termed the "biological market theory."And, as it turns out, female spider monkeys want often access to infants. Many primates are "intensely interested in other females' infants" and will spend an amazing amount of time with infants, even investing a great deal of time caring for and interacting with infants that are not their own. Strong attraction to infants is thought to be adaptive, as females that are highly motivated to interact and care for young make good mothers.So, based on these findings, might primates "trade" social/affiliative behaviors for access to infants? As it turns out, yes.Researchers studied a group of females, monitoring the frequency of approaches and social/affiliative interactions (e.g. "embraces"* and grooming behavior) that each female received and comparing the effect of motherhood and of infant presence. While the presence of infants didn't affect the frequency of these social interactions,[F]emales received significantly more approaches and embraces when they were mothers compared to all other times. As mothers, they received significantly more embraces than they gave indicating that the increase in friendly behaviour received was due to increased interest from other females and not simply a general increase in socialityBut strikingly, mother and non-mother females were groomed with similar frequency, suggesting that both "embraces" and grooming behaviors can (but may not necessarily) act as "traded" commodities. And trading reflected changes in the behavioral market, as:the proportion of embraces given to mothers followed by infant handling was dependent on the number of infants available in the community. When fewer infants were present, one embrace procured significantly fewer bouts of infant handling.Cutely, it sounds like this is a within-species phenomenon, as embraces "initiated by the handler were less likely to be reciprocated by the mother...and were significantly affected by infant availability." Can't you just see the researcher trying this out?The biological market theory has been challenged as a model that overstretches what others consider to be a "general relationship expressed in partner preferences, social grooming, and agonistic aiding,"and that these relationships are better predictors of how grooming and infant handling behaviors might occur. But it certainly makes for a sensical argument in a highly social population of affiliative primate species.* As defined by co-author K. Slater in a Discovery writeup: "An embrace is defined as one monkey approaching another monkey and wrapping their arms around them." I cringed at Discovery's anthropomorphization of this "hugging" behavior but used their image, above. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=870700 Fri, 14 Sep 2007 12:12:00 +0100 870700 http://anteriorcommissure.blogspot.com/2007/09/not-so-productive-day.html If you haven't already visited their site, xkcd has some fantastically funny and tragically accurate comics on graduate life. Here's a recent (and particularly identifiable) strip:And here's the version, slightly altered, that I made to reflect today's particular productivity:Three reams of computer paper = $20Two entire ink cartridges = $60Five binders = $50Having time to reformat an online comic to reflect my entirely unproductive day (except for said printing project), due only to a lack of desk-chair sparring partners = priceless If time was money, I'd toss in my fifteen emails coordinating my proposal date, and the grey hair that sprouted when I actually set it. But time is never money in graduate school, so I must abstain :) (I promise to post something more substantial when my day isn't interrupted every two minutes) (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=869668 Thu, 13 Sep 2007 21:53:00 +0100 869668 http://anteriorcommissure.blogspot.com/2007/09/quick-note-on-my-coffee-addiction.html I quit drinking coffee exactly 11 days ago. Following a massive two-day headache while my body detoxified, I actually felt pretty good. Less tired, more energetic, a couple of extra dollars in my pocket.Then I see articles like this and break like a skinny little twig. I'm happily sipping my first cup since then.At least it packs a bit more punch than it used to. Maybe my brief hiatus downregulated my adenosine receptors. I remain, however, a caffeine-sensitive individual. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=867437 Wed, 12 Sep 2007 15:20:00 +0100 867437 http://www.blogger.com/video-play.mp4?contentId=1e60a18cb7fed9a5&type=video%2Fmp4 Food-sharing between mothers and infant chimpanzees is considered to be a form of parental investment, in which the mother shares food to enhance the strength, development, and viability of her offspring. While mothers won't share the most appetizing parts of their meals with their infants, their food-sharing behavior may facilitate the transition from nursing to food sampling and independent foraging.But recently, food-sharing between adult chimpanzees has been observed. More strikingly, this occurs between unrelated adults. Sharing food with non-relative members of a highly social population could serve to bolster and strengthen the numbers of group members, conferring additional safety and protection via group augmentation. Sharing food also prevents harassment from begging group members. Some researchers propose that food-sharing may represent altruism, though others argue that sharing behavior is actually competitive and not altruistic at all.And now, an additional explanation has emerged: food-sharing may impress the ladies.Researchers studied chimpanzee food-sharing behavior in Bossou, Guinea, a long-term field study site. And revealed some intriguing findings, published in PLoS ONE.While male chimps won't frequently share wild-grown plant food, males would frequently share cultivated plant food - particularly papayas - that they had stolen from nearby farms or orchards:[A]dult males shared crops...overwhelmingly with these females [92% of sharing events] particularly with one cycling female [60% of sharing events] who took part in 83% of all consortships with males.Males displayed more anxiety-like behaviors when stealing food when local people were around versus when they were on their own, but continued to steal food consistently over a period of months. And males rarely shared the stolen food with each other.Researchers propose that this gender-specific food-sharing may represent an effective social strategy for garnering attention and drawing the favor of reproductively receptive females. By sharing food with females, males may solidify social bonds and improve the female's "good will" toward them, potentially increasing the chance of future mating opportunities. And, researchers add, daring behavior like food stealing may actually be an attractive trait that represents dominance or courage.So next time you're courting a female, any good impression earned by a lovely bouquet of flowers may be readily trumped by a stolen fruit basket. Mull it over. And then go do your own research. :)A video of food-sharing between an adult male and unrelated adult female, compliments of the PLoS paper: MSNBC also has a writeup. image (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=865663 Wed, 12 Sep 2007 12:56:00 +0100 865663 http://anteriorcommissure.blogspot.com/2007/09/upcoming-lecture-on-science.html We've just finalized a fantastic panel of speakers for our upcoming lecture hosted by the Science Communication Consortium.Panel DiscussionHow various media outlets are used to popularize, communicate & promote scienceThursday, October 18th at 7pmNew York University (room TBA)Panelists will include:Christopher Mims is the special projects editor at Scientific American dot com. In his former role as online editor at Seed Magazine, he built scienceblogs dot com.Ann Marie Cunningham is a science journalist who began in magazines and books, and has moved into broadcasting and Webcasting. She is now a contributing producer to NPR's Talk of the Nation: Science Friday and its Web features and acts as Executive Director to TalkingScience, Science Friday's nonprofit arm.Kitta MacPherson has been The Star-Ledger's science writer since 1983. She strives daily to provide clear, concise prose about science for the intelligent "laypeople" who are her readers.David Levine is Senior Director in the Office of Communications and Marketing for the New York City Health and Hospitals Corporation. Prior to that, Mr. Levine was Director of Media Relations for the American Cancer Society. He also worked as a medical editor/writer for Pfizer Inc and has published a number of scientific articles for lay audiences.The discussion is timely and should be extremely interesting to science writers, journalists, authors, scientists, and lay people. And, of course, it will be followed by a networking reception.Also, our kick-off lecture on democratic citizenship and scientific communication by an extremely brilliant mind and one of my favorite academics, Dr. Sheila Jasanoff, is quickly approaching - go register to attend on Thursday, Sept 27th! (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=862219 Tue, 11 Sep 2007 02:13:00 +0100 862219 http://anteriorcommissure.blogspot.com/2007/09/don-mess-with-baby-maternal-defense-in.html Some parts may be a bit difficult to watch, but wildebeest aficionados need not fear - the infant survives.A well-documented characteristic of the maternal mammal is how vigorously she will defend her offspring from intruders, predators, and nosy members of her own species. As do most mammals, female rats express strikingly low anxiety levels during the period immediately after birth. Researchers (e.g. JS Lonstein 2005) have since discovered that it is the interactions between the female and her offspring that reduce the mother's fearfulness and anxiety exclusively during this time - in rats, extended breaks from offspring quickly cause anxiety levels to spring back up to normal. The natural anxiolysis caused by offspring is thought to reduce a female's inhibition toward intruders, rendering her unafraid and thus capable of defending her offspring at her own expense.If this video doesn't present an amazing portrayal of just how rigorous maternal defense can be, I'm not sure what will. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=852673 Sat, 08 Sep 2007 22:49:00 +0100 852673 http://anteriorcommissure.blogspot.com/2007/09/two-little-genes-and-great-big.html There's an interesting little tale that's been unfolding in my field, on the influence of two little genes on parental behavior. Two imprinted genes, to be exact.First, a quick overview on genetics (something I'm woefully bad at). Genes come in two copies or alleles - one from each parent. In most autosomal genes, only one allele is expressed, with a 50% chance that it will be the mother's allele and a 50% chance that it will be the father's allele. Alleles that don't share the same probability of being expressed are known as imprinted genes. Some imprinted genes will only expressed if they come from the mother (maternally imprinted), in which case the father's allele is silenced; the opposite, paternally imprinted genes, is also possible.A while back, researchers started exploring a paternally imprinted gene called Peg1 (or Mest), inhereted from the father. When they silenced Peg1 in a strain of mice, maternal behavior was severely disrupted - females had normal pregnancies and deliveries but neglected to take care of their young. When a similar gene, Peg3, was silenced, females again neglected to behave maternally, which ultimately resulted in the death of most offspring.What's more, female mice with silenced Peg1 and Peg3 delivered much smaller offspring, expressed placental defects, and their offspring had dramatically reduced survival rates. How low? In the Peg3 study, less than 10% of offspring from mutant females lived until weaning (in rats, a platry 23 days; mice is something similar), compared to over 83% in wild-type, Peg3-expressing females.The first, most natural question to ask would be whether silencing Peg1 and Peg3 changed the female's hormones and thus disrupted her pregnancy, delivery, and postpartum care of offspring. Might the allele code for hormones important in the regulation of parental care? Doesn't seem to be the case. And female's olfactory and motor systems remained intact and functional.Instead, researchers have proposed that these paternally imprinted genes may reflect "parental conflict", explained nicely here:According to this "conflict theory," the paternal genes endeavor to obtain maximum resources from the mother, at the expense of future offspring who may have different fathers... The conflict gets played out most visibly in metabolically costly processes, such as growth and development of the placenta and postnatal feeding of the offspring... [Thus] the paternal genome seems to code for a big placenta and robust offspring.But a big placenta and strong, healthy offspring are extremely taxing to the mother. Acccording to the same theory, she wants to bear as many litters as quickly as possible, minimally investing in each litter in order to move on to the next. And hence, the "parental conflict" arises. Lacking regulation from paternally imprinted genes, then, females with silenced Peg1/3 are able to "pursue" her own reproductive prerogative, including the conservation of resources. No robust offspring for her - sheer numbers are just fine.It's an interesting concept, and one I'd been meaning to post on for a while. It certainly seems adaptive. Doesn't it just make intuitive sense to you?There are some intriguing evidence for epigenetic modification of Peg, as well, which we may revisit sometime soon... (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=850655 Fri, 07 Sep 2007 12:40:00 +0100 850655 http://anteriorcommissure.blogspot.com/2007/09/hear-what-im-writing.html Mo has posted an awesome explanation of synesthesia, in which a person conflates different senses (e.g. hears colors or finds words to have texture), that is an absolute must-read.Synesthesia is one of the most intriguing phenomena in the field of neuroscience, and since I've turned to posts on reproduction and parental behavior, it's nice to read something that bring me back to some of my broader field's most intriguing research. (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=841894 Wed, 05 Sep 2007 04:41:00 +0100 841894 http://anteriorcommissure.blogspot.com/2007/09/men-like-good-looking-women-or-argument.html Thanks for another good chuckle, FoxNews. This time, it's the headline that got me: "Earth-Shattering Study: Men Like Good-Looking Women"Which is laughable...until you find out that the study is published in PNAS. I don't think I'm going out on a limb here when I say that that's a fairly prestigious journal. So, I checked the current PNAS issue and two prior issues for the original study. How am I missing the article? If someone can locate it, I'd really appreciate a link...Resorting to excerpts from the writeup:Participants ranged in age from 26 to their early 40s and took part in "speed dating," short meetings of three to seven minutes in which people chat, then move on to meet another dater.After the session, the researchers compared what the participants said they were looking for with the people they actually chose to ask for another date.Men's choices did not reflect their stated preferences, the researchers concluded. Instead, men appeared to base their decisions mostly on the women's physical attractiveness.Shocking, I know. I particularly enjoyed this part:The men also appeared to be much less choosy. Men tended to select nearly every woman above a certain minimum attractiveness threshold, [researcher] Todd said.Aside from the fact that common bar conversation amongst friends has seemingly evolved into PNAS-worthy research, this is proof of the pudding. Men are attracted to good-looking women.But what makes someone attractive?One common theme pursued by researchers is the idea of facial symmetry. Faces with a high degree of symmetry are typically considered more attractive.* Symmetry has been associated with good health and genetic quality (or "phenotypic condition"). It's been proposed that asymmetry might reflect genetic factors that would "disturb bilateral symmetry" in a developing animal. If that developing animal is one's offspring, it makes a good deal of sense that we'd look for genes that would promote even-keeled development across the midline, right?But some convincing evidence suggests that it's not the symmetry as much as the expressiveness and emotionality of a face. A study manipulated the features of asymmetric faces and found that, when the features were altered to enhance the symmetry of the face, the face was rated as less attractive. I'm not sure how much distortion occurred, but researchers believed that the newly symmetric faces were less attractive "because of the reduction of natural directional asymmetries, perhaps making the faces appear unemotional.Nevertheless, patterns in facialmetric characteristics (yes, that's the actual term) emerge consistently. Men are apparently judged on the angle between their eyes and mouth (see image at right; here for cite) and are considered more attractive based on cheekbone prominence, facial length and Geico Man-like forehead height. Those who have higher levels of testosterone are typically ranked as having more masculine faces, associated with the above characteristics. Women may use facial attractiveness as a proxy measure for a male's physical strength. And men, take note: if a women doesn't find you attractive at first glance, try again in a few weeks. It turns out that facial attractiveness fluctuates with a female's menstrual cycle and peaks at ovulation.And, surprisingly, men's perceived attraction to infants predicted whether females would be attracted to their face. Turns out that Potential Mom is looking for a good-looking mate and father.I could find considerably less research regarding female's facial attractiveness. One study found that "hyperfeminine" characteristics, such as a small pointed chin, are considered most attractive, and that such characteristics are separable from sexually dimorphic development. The symmetry argument appears consistent in ladies as well.Unfortunately for our perpetually youthful-looking friends of both sexes, babyfaceness isn't associated with attractiveness. Less wrinkles as you age, perhaps, but not attractiveness.Researchers have proposed that our decisions of whether we find someone attractive may be due to hormones that we were exposed to in utero or during puberty, our heavy reliance on visual information (based on the brain size and capacity of us large-brained mammals), our innate information-processing systems used to recognize or perceive, or our desire to pass "attractive genes" to our offspring so that they might have a higher probability of finding a mate and consequent reproductive success.**I've discussed facial attractiveness with the intentional omission of physical (i.e. corporal) attractiveness. I imagine this self-evident component of speed-dating, particularly related to males' snap perceptions, is partially what FoxNews was giggling about. But I'll return to this issue in a future post...* I heard somewhere that, of all people, Bill Clinton has an extremely symmetrical face. Anyone?** A good review covers a few of these in more detailimage 1 and 2 (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=841895 Wed, 05 Sep 2007 02:33:00 +0100 841895 http://anteriorcommissure.blogspot.com/2007/09/im-late-for-blog-day.html But here are five recommended blogs that you should check out:A Well-Timed Period - on women's health and reproductionFemale Science Professor - on a woman's experience running her own lab and fighting her way through a male-dominated fieldCocktail Party Physics - already well-known, but her science is gorgeously & delectably detailedPonderings of a Fool - a kindred spirit in the biological sciencesFor good measure, one delightful non-scientific blog:Lowercase l - my favorite new discovery of the year; whimsical photos of delightfully misplaced lowercase ls on signs posted across the world.And one non-blog site to visit:Made with Molecules - an inspired PhD scientist who makes beautiful structural-bio jewelry; I've gifted her earrings to many labmates and my advisor (Source: The Anterior Commissure) The Anterior Commissure blogs http://www.medworm.com/rss/comments.php?id=836953 Sun, 02 Sep 2007 17:03:00 +0100 836953 http://anteriorcommissure.blogspot.com/2007/09/kiss-and-tellit-to-scientist.html Once and a while, I read a research study and think, "Scientists think up the strangest questions to answer," then, more often than not, get completely sucked into their findings. A recent study on romantic kissing out of Canada, which Thomas passed along to me, is a real gem.There's some evidence for kissing-like behavior in other, non-human primates but, as we can't infer that non-humans have romantic feelings and/or listen to Barry White, we'll stick with humans today.The full paper set out to investigate the function of romantic kissing behavior in short- and long-term relationships. The most readily available population of kiss-happy subjects? Undergraduates, of course. A cute thing for couples to go do together, once the novelty of movie-and-dinner dates starts to wane.Three possible functions of kissing were under investigation:1. Mate assessment. Swapping spit may provide important insight into your partner's biology: researchers argue that saliva taste and, yes, odor may clue you in to your partner's health problems or transmit pheromones that allow you to bond with or assess the reproductive capacity of their mate. As