Brain and Behavior
goodmath | January 19, 2007 I decided that for today, I'd show the most thoroughly evil programming language ever
devised. This is a language so thoroughly evil that it's named Malbolge after a circle
of hell. It's so evil that it's own designer was not able to write a hello world program! In
fact, the only way that anyone managed to write a "Hello World" was by designing a genetic algorithm
to create one. This monstrosity is so thoroughly twisted that I decided to put it in the "Brain and Behavior" category on ScienceBlogs, because it's a demonstration of what happens when you take a brain, and twist it until it…
cortex | January 16, 2007What is the neural correlate of the self? The easy answer is that nobody knows. We have yet to discover a neurological patient who has lost their sense of identity, but still retained their conscious sensations. Nevertheless, certain brain areas have been implicated in distinguishing the self from non-self.
This 2006 paper by Todd Heatherton of Dartmouth, for example, detected increased activity in the medial prefrontal cortex (mPFC) when people were forced to perform "self-referrent tasks". In other words, the mPFC is what recognizes your reflection in the mirror. It might not be the…
developingintelligence | January 16, 2007Suppose that "memory task A" shows marked improvement at 5 months, but "memory task B" doesn't show marked improvement until 9 months. Before we can make inferences about the development of memory, we need to understand how tasks A and B differentially strain the developing cognitive system.
Along these lines, Gross et al.'s 2002 Developmental Psychobiology article investigates the relationship of three different memory tasks in 6-month-old infants. The tasks are pretty representative of current behavioral work with human infants:
1) In the mobile conjugate reinforcement paradigm, infants…
cortex | January 16, 2007John Tierney inaugurates his new Science Times column with a charming mediation on a recent neuroeconomics paper published in Neuron:
The economists teamed with psychologists at Stanford to turn an M.R.I. machine into a shopping mall. They gave each experimental subject $40 in cash and offered the chance to buy dozens of gadgets, appliances, books, DVDs and assorted tchotchkes. Lying inside the scanner, first you'd see a picture of a product. Next you'd see its price, which was about 75 percent below retail. Then you'd choose whether or not you'd like a chance to buy it. Afterward, the…
clock | January 13, 2007There's No Scent Like Home: New Research Shows Larval Fish Use Smell To Return To Coral Reefs:
Tiny larval fish living among Australia's Great Barrier Reef spend the early days of their lives swept up in ocean currents that disperse them far from their places of birth. Given such a life history, one might assume that fish populations would be genetically homogeneous within the dispersal area. Yet the diversity of reef fish species is high and individual reefs contain different fish populations. For such rich biodiversity to have evolved, some form of population isolation is required. New…
developingintelligence | January 13, 2007Recent highlights from the brain blogosphere:
Can crossword puzzles help prevent senile dementia?
The current state of the brain fitness movement: as evaluated by the New York Times.
Spindle neurons evolved very recently - are they also the source of frontal dementia?
A new form of pharmacological brain enhancement - could this technique avoid the long-term risks of excitotoxicity (as might result from extensive use of ampakines?)
What about interrogation neurotechnology? Here's what military's director of psychopharmacology has to say.
Future prospects for interrogation neurotech.
Bird…
developingintelligence | January 11, 2007As enigmatic as prefrontal function seems to be, the anterior portions of prefrontal cortex (aPFC) are even more mysterious. This results partly from the fact that aPFC is particularly difficult to access and study electrophysiologically in nonhuman primates, as Ramnani and Owen note in their 2004 Nature Reviews Neuroscience article, and so detailed neuroanatomical investigations of aPFC have been conducted only recently. The authors report how this work has led to a breakthrough in the understanding of aPFC's computations.
Ramnani and Owen review Brodmann's early analysis of aPFC, also…
developingintelligence | January 9, 2007Although much progress has been made since neurologist Richard Restack called the brain one of science's last frontiers, the functions of some brain areas remain mysterious. Foremost among these is prefrontal cortex (PFC), a region that is much reduced in size in most other primates, is among the last areas to develop in human children, and yet is active in almost every cognitive task.
In general, prefrontal cortex is associated with higher-order cognition, such as those processes involved in planning, strategizing, self-monitoring, self-regulation, and more generally, the coordination of…
cortex | January 9, 2007According to a new study published in the BMJ, the Danish are happier than people in other developed nations because they have low expectations. That's the dismal secret of happiness: not expecting very much from life in the first place.
"It's a David and Goliath thing," said the lead author, Kaare Christensen, a professor of epidemiology at the University of Southern Denmark in Odense. "If you're a big guy, you expect to be on the top all the time and you're disappointed when things don't go well. But when you're down at the bottom like us, you hang on, you don't expect much, and once in a…
developingintelligence | January 8, 2007In a few places throughout the second edition of his landmark book, Mark Johnson suggests that the field of developmental cognitive neuroscience has matured from infancy to toddlerhood. This book, then, is a sort of biography, from the field's theoretical ancestry in 17th century debates between "vitalists" and "preformationalists" to current (and in some ways similar) debates between nativists and empiricists. In between, Johnson expertly covers everything from prenatal cortical differentiation to developmental change in the distributions of various neuromodulators, to the development of…
grrlscientist | January 6, 2007
The internet connection was down for nearly 24 hours at the hotel, so I was unable to update you all on the talks I attended yesterday afternoon, which caused me to express much crankiness. Hopefully, I will be able to get that done sometime within the next 24 hours (i.e.; before I return to NYC). Today is the third day of the conference and I am getting tired and overwhelmed by the intense flood of presentations and posters, so now I am attending only presentations that focus explicitly on evolutionary biology or ornithology. Below the fold are the bird presentations that I attended;
Beck…
grrlscientist | January 5, 2007
I spent my morning going to presentations in the Hormones, Brain and Behavior section, which is the area that I studied for my doctoral degree before I switched fields to evolution and phylogenetics. Some of the presentations I saw included;
Hau. Evidence from studies in temperate-zone male vertebrates has accumulated that the endocrine regulation of aggressive territorial behavior differs seasonally. During the breeding season a combination of androgenic and estrogenic mechanisms appear to regulate male aggressive behavior, while during the non-breeding season either only estrogenic or non…
purepedantry | January 3, 2007Grrrr. Tell me if this article bugs you as much as it does me:
Social Dementia' Decimates Special NeuronsBy Michael Balter
Being human has its pluses and minuses. Our cognitive powers are superior to that of other animals, and we can act consciously to alter our destinies. On the other hand, our highly evolved brains are prone to serious malfunctions such as mental illness and dementia. Now a team of neuroscientists has found that some of these blessings and curses might be linked to the same specialized neural circuits.
In 1999, researchers discovered that the brains of humans and great…
developingintelligence | January 3, 2007The prefrontal cortex is a major recipient of subcortical dopaminergic projections. Accordingly, almost all of the behavioral tasks that are known to critically depend on the prefrontal cortex are sensitive to dopamine levels. A curious exception is the Self Ordered Pointing task (SOPT), in which subjects must select each of 9 designs by pointing at each one once; after each selection, the locations of the designs are randomized. Therefore, in order to succeed at this task subjects must remember the designs themselves and not the locations to which they pointed.
The dorsolateral…
developingintelligence | January 2, 2007It seem reasonable that evolution might select for adaptive behaviors by increasing the relative size of particular brain regions that support those behaviors; for example, bats might have an enlarged auditory cortex since they navigate with echolocation. To some extent this does happen, but such differences are often apparent only after controlling for a much larger source of variance: changes in brain size that correlate with changes in body size - and the implications of this fact are wide-reaching.
As Barbara Finlay and coauthors wrote in this 2001 Behavioral and Brain Sciences article,…
dmunger | January 2, 2007Chris Chatham's Developing Intelligence, one of my favorite CogSci blogs, is now a member of ScienceBlogs! Chris has a sharp mind, and he's always willing to offer thorough, readable accounts of peer-reviewed research. Now you'll be able to get his insights alongside the other great resources for cognitive and neuroscience we have here at ScienceBlogs. You can see all posts on Brain and Behavior using the Brain and Behavior Channel, or visit the blogs individually via the handy listing in the column over at left. But you'll probably want to start with Chris's latest, a great post on fMRI…
clock | January 1, 2007 If you are interested in the background and recent history of the research on mammalian SCN in line of Erik Herzog's work I described in VIP synchronizes mammalian circadian pacemaker neurons and A Huge New Circadian Pacemaker Found In The Mammalian Brain, you may want to look at these old Circadiana posts as well:
-----------------------------Cutting Edge: Circadian Rhythm of Astrocytes (February 02, 2005):
Erik has done it again. He is not one to publish 30 papers per year, but whenever he publishes one, it always gives me the chills and thrills! What beautiful science:
Circadian Rhythm…
retrospectacle | December 31, 2006Most people who have known a drug addict, or have watched Trainspotting or ER, know that one of the more insidious parts of addiction is the need for more and more drug to achieve a "high." This leads the addict into a spiral of drug-seeking behavior, and brain changes, which lead to the person just trying to feel normal again. Why is it that, over time, opiate drugs lose their rewarding effects? Until recently, the molecular mechanism behind "why" was unknown, but a new study published in Nature (subscription required) this month explains that has to do with the decrease of a certain…
purepedantry | December 28, 2006The Economist has an article that wonders whether new knowledge into neuroscience and more particularly social pathologies will erode our belief in free will. I roll my eyes every time I read an article like this one, mostly because they tend to express an uniformed view about how the brain works:
For millennia the question of free will was the province of philosophers and theologians, but it actually turns on how the brain works. Only in the past decade and a half, however, has it been possible to watch the living human brain in action in a way that begins to show in detail what happens…
cortex | December 21, 2006My last post on neuroscience and free will generated lots of interesting comments. Please check them out. But I think a few readers misunderstood my ambition. It's easiest to begin by saying what I wasn't trying to do: I wasn't trying to construct a philosophically sound defense of free will (I'm not sure such a thing is possible), or reflect on quantum indeterminacy, or get into a metaphysical debate about the material causality of everything. If you believe, ala Laplace, that the world is governed by a discrete set of material rules (as I do), then, of course, freedom doesn't really exist.…