Brain and Behavior
razib | April 24, 2008Genetic variation in human NPY expression affects stress response and emotion:
Understanding inter-individual differences in stress response requires the explanation of genetic influences at multiple phenotypic levels, including complex behaviours and the metabolic responses of brain regions to emotional stimuli. Neuropeptide Y (NPY) is anxiolytic...and its release is induced by stress...NPY is abundantly expressed in regions of the limbic system that are implicated in arousal and in the assignment of emotional valences to stimuli and memories...Here we show that haplotype-driven NPY…
clock | April 24, 2008Nurture Over Nature: Certain Genes Are Turned On Or Off By Geography And Lifestyle, Study Suggests:
Score one for the nurture side of the nature vs. nurture debate, as North Carolina State University geneticists have shown that environmental factors such as lifestyle and geography play a large role in whether certain genes are turned on or off. By studying gene expression of white blood cells in 46 Moroccan Amazighs, or Berbers - including desert nomads, mountain agrarians and coastal urban dwellers - the NC State researchers and collaborators in Morocco and the United States showed that up…
hrynyshyn | April 24, 2008Warning: Anyone who takes this post seriously please resist the temptation to comment.
Over the reported objections of John McCain and national GOP officials, North Carolina's state Republican party is about to run a campaign ad attacking Barack Obama for consorting with Jeremiah Wright. The ad disingenuously implies that Obama was sitting in the congregation when Wright made some of his more inflammatory remarks condemning America, even though there is no evidence to suggest that Obama was anywhere near the church at the time. Why are these kinds of dirty campaign tricks invariably the…
clock | April 24, 2008This post (click on the icon) was originally written on May 07, 2005, introducing the topic of neuroendocrine control of seasonal changes in physiology and behavior.
So far, I have directed all my attention to daily - circadian - rhythms, and pretty much ignored other rhythms that correspond to other cycles in nature. Another obvious cycle in nature is the procession of seasons during a year.
Just as an environment during the day is different from the same environment during the night and thus requires different adaptations for survival, so the winter environment and the summer environment…
clock | April 23, 2008There are 41 new articles published this week in PLoS ONE. A always, make comments and ratings while browsing and reading the articles. Here are just a few picks - titles I found interesting - but you should go and check all the others as well:
Nutrition or Detoxification: Why Bats Visit Mineral Licks of the Amazonian Rainforest:
Many animals in the tropics of Africa, Asia and South America regularly visit so-called salt or mineral licks to consume clay or drink clay-saturated water. Whether this behavior is used to supplement diets with locally limited nutrients or to buffer the effects of…
purepedantry | April 23, 2008(I have been meaning to post this for about two weeks, so if it is a bit dated forgive me.)
Dyslexia is a learning disability characterized by slower reading skills acquisition, and it is associated with certain structural abnormalities in the brain. However, it turns out that different areas of the brain are affected depending on whether your language is alphabetic (like English) or symbolic (like Chinese).
Siok et al. present evidence in PNAS that English and Chinese languages utilize different brain systems and that as a consequence dyslexia presents differently in English and Chinese…
clock | April 22, 2008Neanderthals Speak Again After 30,000 Years:
Dr. Robert McCarthy, an assistant professor of anthropology in the Dorothy F. Schmidt College of Arts and Letters at Florida Atlantic University, has reconstructed vocal tracts that simulate the sound of the Neanderthal voice.
Slowly-developing Primates Definitely Not Dim-witted:
Some primates have evolved big brains because their extra brainpower helps them live and reproduce longer, an advantage that outweighs the demands of extra years of growth and development they spend reaching adulthood, anthropologists from Duke University and the…
dmunger | April 22, 2008Do we have free will? While some may see the question as trivial, it's a challenging topic that has been actively debated for centuries. Whether or not you believe a god is involved, a case can be made that free will is simply an illusion, and that every "decision" we make is completely controlled by factors outside of an individual's control.
Yet others have argued that a belief in free will is essential to morality. If we don't actually have any control over the decisions we make, how can we be held accountable for them? Several studies have suggested that when kids believe their…
cortex | April 22, 2008Crazy stuff, courtesy of John Tierney:
The natural impulse to stop holding your breath (typically within 30 seconds or a minute) is not because of an oxygen shortage but because of the painful buildup of carbon dioxide. Mr. Blaine said he began trying to overcome that urge when he was a child in Brooklyn and at age 11 managed to hold his breath for three and a half minutes.
In his current training, he said, he does exercises every morning in which he breathes for no more than 12 minutes over the course of an hour, and he sleeps in a hypoxic tent in his Manhattan apartment that simulates the…
clock | April 21, 2008This is a summary of my 1999 paper, following in the footsteps of the work I described here two days ago. The work described in that earlier post was done surprisingly quickly - in about a year - so I decided to do some more for my Masters Thesis.
The obvious next thing to do was to expose the quail to T-cycles, i.e., non-24h cycles. This is some arcane circadiana, so please refer to the series of posts on entrainment from yesterday and the two posts on seasonality and photoperiodism posted this morning so you can follow the discussion below:
There were three big reasons for me to attempt…
razib | April 21, 2008Vitamin D Important In Brain Development And Function:
McCann & Ames point out that evidence for vitamin D's involvement in brain function includes the wide distribution of vitamin D receptors throughout the brain. They also discuss vitamin D's ability to affect proteins in the brain known to be directly involved in learning and memory, motor control, and possibly even maternal and social behavior. The review also discusses studies in both humans and animals that present suggestive though not definitive evidence of cognitive or behavioral consequences of vitamin D inadequacy. The authors…
oracknows | April 21, 2008A couple of weeks ago, I commented about a frivolous, SLAPP-style subpoena directed at one of the most thorough, rational bloggers about autism out there, Kathleen Seidel by Clifford Shoemaker, the attorney for Rev. Lisa Sykes and her husband Seth Sikes, both of whom who are suing Bayer for alleged "vaccine damage" as a cause of their child's autism. The subpoena in question, issued mere hours after Seidel published a well-researched but particularly unflattering post about Clifford Shoemaker's activities suing vaccine manufacturers, was so obviously a fishing expedition designed to…
clock | April 20, 2008One of the important questions in the study of circadian organization is the way multiple clocks in the body communicate with each other in order to produce unified rhythmic output.
In the case of mammals, the two pacemakers are the left and the right suprachiasmatic nucleus (SCN). The tow nuclei are anatomically close to each other and have direct nerve connections between them, so it is not difficult to imagine how the two clocks manage to remain continuously coupled (syncronized) to each other and, together, produce a single output, thus synchronizing all the rhythms in the body.
In the…
clock | April 20, 2008The third post in the series on entrainment, first written on April 10, 2005, starts slowly to get into the meat of things...As always, clicking on the spider-clock icon will take you to the site of the original post.
In the previous post, I introduced the concept of entrainment of circadian rhythms to environmental cycles. As I stated there, I will focus on non-parametric effects of light (i.e., the timing of onsets and offsets of light) on the phase and period of the clock.
Entrainment is a mechanism that forces the internal period (&tau - tau) of the biological clock to assume the…
clock | April 19, 2008One of the assumptions in the study of circadian organization is that, at the level of molecules and cells, all vertebrate (and perhaps all animal) clocks work in roughly the same way. The diversity of circadian properties is understood to be a higher-level property of interacting multicelular and multi-organ circadian systems: how the clocks receive environmental information, how the multiple pacemakers communicate and synchronize with each other, how they convey the temporal information to the peripheral clocks in all the other cells in the body, and how perpheral clocks generate…
ejohnson | April 18, 2008For your viewing pleasure, here are the large versions of this week's channel photos (but don't lose the love for the little ones!).
(Have a photo you'd like to send in? Email it to photos@scienceblogs.com, or assign the tag "sbhomepage" to one of your photos on Flickr. Note: be sure to assign your photo an "attribution only" or "share and share alike" Creative Commons license so that we can use it.)
First photo here, the rest below the fold.
Life Science. From Flickr, by Joi
Physical Science. The polished surface of malachite. From Flickr, by kevinzim
Environment. A dry lake bed in…
clock | April 18, 2008Going into more and more detail, here is a February 11, 2005 post about the current knowledge about the circadian organization in my favourite animal - the Japanese quail.
Japanese quail (Coturnix coturnix japonica), also known as the Asian Migratory Quail, are gallinaceous birds from the family Phasianidae, until 1960s thought to be a subspecies of European migratory quail (Coturnix coturnix coturnix), but now considered to be a separate species, designated as Coturnix japonica. The breeding range of the wild population encompasses Siberia, Mongolia, northeastern China and Japan, while the…
clock | April 17, 2008
A January 20, 2006 post placing a cool physiological/behavioral study into an evolutionary context.
There are two main hypotheses - not mutually exclusive - for the adaptive value of having a circadian clock. One is the Internal Synchronization hypothesis, stating that the circadian clock serves to synchronize biochemical and physiological processes within the body. The second is the External Synchronization hypothesis, stating that the circadian clock serves to syncronize the physiology and behavior to the natural environment.
The prediction from the Internal Hypothesis is that circadian…
clock | April 17, 2008 This post was originally written on February 11, 2005. Moving from relatively simple mammalian model to more complex systems.
I have previously described the basic properties of the circadian organization in mammals. Non-mammalian vertebrates (fish, amphibians, reptiles and birds) have more complex circadian systems than mammals. While the suprachiasmatic area remains a site of circadian pacemakers, it is, unlike in mammals, not the only such site.
The pineal organ, which in mammals is a purely secretory organ, is directly photosensitive in other vertebrates (with the exception of snakes)…
sb admin | April 16, 2008Today the Washington Post, Los Angeles Times, and other news sources report that the National Toxicology Program has issued a draft brief stating concerns about the effects of low levels of bispehnol A on fetusus and children. Exposure to bisphenol A can interfere with the development of children's brains and reproductive organs, including alterations to breast and prostate tissues that can incrase the risk of developing cancer later in life. Bisphenol A is used in many plastics and in the liners of some food and beverage containers, and most of us have measurable concentrations of it our…