Saturday, February 25, 2006

Even more brainy genes --- finale


As a finale to the two previous posts about brain evolution, let me end by referring to this study by Mekel-Bobrov et al in Science. If you have followed blogs such as John Hawks, Gene expression or The Scientist you have probably heard about this story before.

The study "Ongoing Adaptive Evolution of ASPM, a Brain Size Determinantin Homo sapiens" has the following abstract:

"The gene ASPM (abnormal spindle-like microcephaly associated) is a specific regulator of brain size, and its evolution in the lineage leading to Homo sapiens was driven by strong positive selection. Here, we show that one genetic variant of ASPM in humans arose merely about 5800 years ago and has since swept to high frequency under strong positive selection. These findings, especially the remarkably young age of the positively selected variant, suggest that the human brain is still undergoing rapid adaptive evolution."

So the brain has developed significantly during the past 6000 years or so? That is indeed an interestring finding. So what does the ASPM do? What is it related to? Let me recap a brief survey of Hubmed search for "ASPM and brain".
  • It is related to microencephaly and seizures (1)
  • It is also related to cortical malformation (2)
  • The pathological changes are caused by deficient neurogenesis within the neurogenic epithelium (3)
  • It has been strongly positively selected since the divergence from our common ancestor to the chimp (4)
The list goes on and on, but these are maybe the most prevalent reports and topics.

But listen: we're back to discussing brain size again, right? As I claimed in my first brain-evo post "brain size" can mean a lot of things. Since the brain does not evolve like an inflating balloon, it would be much more interesting to know what parts of the brain that increase in size. I'll bet a dollar that we find the prefrontal cortex driving much of this evolution, but that should also mean that the PfC-connected areas would increase in size, too.

I'm diving more into this matter now, and immediately find some interesting and critical remarks by other blogs: again, John Hawks and Gene Expression share their view in the most eloquent way. Read and learn, and don't forget to speculate about what that ASPM haplotype world map actually might mean.

References

(1) ASPM mutations identified in patients with primary microcephaly and seizures. Shen J, Eyaid W, Mochida GH, Al-Moayyad F, Bodell A, Woods CG, Walsh CA. J Med Genet. 2005 Sep ; 42(9): 725-9

(2) Cortical malformation and pediatric epilepsy: a molecular genetic approach. Mochida GH.
J Child Neurol. 2005 Apr ; 20(4): 300-3

(3) Autosomal recessive primary microcephaly (MCPH): a review of clinical, molecular, and evolutionary findings. Woods CG, Bond J, Enard W Am J Hum Genet. 2005 May ; 76(5): 717-28

(4) Adaptive evolution of ASPM, a major determinant of cerebral cortical size in humans. Evans PD, Anderson JR, Vallender EJ, Gilbert SL, Malcom CM, Dorus S, Lahn BT Hum Mol Genet. 2004 Mar 1; 13(5): 489-94

Dennett-Ruse exchange leaked

Parts of a private email exchange between philosophers Dan Dennett and Michael Ruse have been published on ID doyen William Dembski's blog. And apparently with the permission on Ruse! Several bloggers have commented on the issues raised by Dennett and Ruse*, but to me the real question is: Why on Earth is Ruse, an avowed Darwinist, forwarding his email to Dembski?

* See:

PZ Myers

Jason Rosenhouse

Chris Mooney

Friday, February 24, 2006

More on continuous brain growth in humans

While we are thinking about brain evolution, consider this study by Evans et al. in Science. They studied the gene Microencephalin (MCPH), which is known for its severe reduction in brain size coupled with mental retardation. Remarkably, despite this abnormality, there is an overall retention of normal brain structure and a lack of overt abnormalities outside of the nervous system. The MCPH function in healthy humans is less well known, and one can speculate whether it has specific brainy advantages to its carrier. As Evans et al conclude in their article:

“[There] could be several possibilities, including brain size, cognition, personality, motor control, or susceptibility to neurological and/or psychiatric diseases.”

What makes this study interesting is the finding that the MCPH has changed during the past ~37.000 years, and that the spread has been fast. In other words there has been a strong positive selection for this gene, indicating that the brain has continued to evolve even in more recent times. The MCPH is also known to be involved in the evolution of hominids, eventually leading to Homo sapiens. The new finding by Evans et al. demonstrates that this trend has been continuing until more recent times, and is there really any reason to think that the same evolutionary trend has stopped?

So evolutionary psychologists be aware -- don’t ever say that today’s humans minds are the same as that of the stone-age man… Of well, to a large extent, it probably is, but this and other similar reports forcefully tells us that we need to unravel the relative contribution of recent evolutionary trajectories in man. It is also necessary to speculate and study the touchy subject on whether there have been local variations in brain size and function according to the recent brain evolutions that have occurred. After all, evolutionary developments about 40.000 years old indicate that there could be geographical variations in the prevalence of this mutation. I don’t think we’ll see yet another claim of the out-of-Africa pertaining to the past 40.000 years or so.

See also comments by John Hawks and Bob Scheid


Here is the abstract from that article:

Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans

Patrick D. Evans in Science, vol. 309, September 2005

The gene Microcephalin (MCPH1) regulates brain size and has evolved under strong positive selection in the human evolutionary lineage. We show that one genetic variant of Microcephalin in modern humans, which arose È37,000 years ago, increased in frequency too rapidly to be compatible with neutral drift. This indicates that it has spread under strong positive selection, although the exact nature of the selection is unknown. The finding that an important brain gene has continued to evolve adaptively in anatomically modern humans suggests the ongoing evolutionary plasticity of the human brain. It also makes Microcephalin an attractive candidate locus for studying the genetics of human variation in brain-related phenotypes.

Wednesday, February 22, 2006

Brainy chromosome


The brain changes continually. Not only during development or ageing, but over generations, too. While the common popular notion is that the human brain of today is identical to that of the stone age man, recent studies of the genetics underlying brain development has shown that the human brain has changed significantly over a far shorter time -- only a few thousand years.

A recent study by Nusbaum et al. in Nature (see full PDF) analysing the human chromosome 8 briefly mentions two regions called the major defensin gene cluster and MCPH1. They speculate that these regions have played a significant role in the expanded brain size that can be observed through hominid evolution.

At the end of the article, Nusbaum et al. open up a whole new field of study:

"(...) the majority of the genes in the region of high divergence in distal 8p play important roles in development or signalling in the nervous system. Notably, the extremely large CSMD1 gene, which lies at the peak of divergence and diversity, is widely expressed in brain tissues. High regional mutation rates and positive selection are generally assumed to be distinct, but it is possible that the former may facilitate the latter by increasing the rate of appearance of potentially advantageous single, or interacting, alleles. It is intriguing to speculate whether the accelerated divergence rate of this region has contributed to the rapid expansion and evolution of the primate brain."

In other words, the study of chromosome 8 might open a whole new field of enquiry about what makes the human brain special. Knowing the genomic makeup of our closes evolutionary peers will also make it possible to study the relative contribution of this region to brain size and, not to forget, the underlying role this change has had for cognitive processes. Yes, brain size is interesting, but at our current standard, we need to know more than that. Increasing brain size is normally NOT thought to work like an inflating balloon where all areas increase equally. Rather, the evolution of areas occur within systems of modules or areas, often underlying one or a few cognitive functions.

Monday, February 20, 2006

Unravelling the evolution of language?


There is now an online-only published paper in PNAS from the Max Planck Institute on the evolution of language. What is surprising is that the researchers have used functional MRI to infer the evolutionary lineage from their results. Basically, what Angela Friederici and her colleagues have done is to compare language processing that is "simple" to processing that is "complex". While simple processing activated left frontal operculum, a phylogenetically older region of the brain, more complex language processing also activated Broca's area, which is thought to be a more recent development specific to humans. in addition, the researchers also studied the white matter connectivity of the two brain regions by using MR tractography. Here, they found that the two regions showed different structural connectivity signatures, further supporting the functional segregation of these two areas.

This makes the researchers conclude:
"Here we report findings pointing toward an evolutionary trajectory with respect to the computation of sequences, from processing simple probabilities to computing hierarchical structures, with the latter recruiting Broca’s area, a cortical region that is phylogenetically younger than the frontal operculum, the brain region dealing with the processing of transitional probabilities"

I first found this through the Max Planck Society press release page. Just reflecting briefly on this, I think that despite the study is interesting itself in terms of functional segregation of language processes, I am not convinced about the argument about the phylogeny of the two regions. As we know from research on subcortical structures such as the "limbic system", we cannot divide between the phylogenetic "old" and limbic brain and the "newer" cortical brain. It is today considered total gibberis, because evolution of "higher" areas in the cortical surface has had a dynamic and synergetic co-evolution of cortical and subcortical areas. In similar vein, I suspect that the evolutionary trajectories of the frontal operculum and Broca's area share a lot, and that a clear-cut division between the two areas will prove hard to make.

Sunday, February 19, 2006

Neuroeconomics and neuromarketing news

Every week there seem to be new papers out on some neuroeconomics or neuromarketing related topic. Let me briefly mention three new papers I’ve stumbled over during the last few days.

[1] In the latest issue of Science a group of researchers at University of Amsterdam report two psychological studies testing how we reach a decision as to what product to buy. Here’s a short description of the first test from Greg Miller’s accompanying news piece:

To test the idea, Dijksterhuis and colleagues asked volunteers to read brief descriptions of four hypothetical cars and pick the one they'd like to buy after mulling it over for 4 minutes. The researchers made the decision far simpler than it is in real life by limiting the descriptions to just four attributes such as good gas mileage or poor legroom. One of the cars had more plusses than the others, and most participants chose this car. But when the researchers made the decision more complex by listing 12 attributes for each car, people identified the best car only about 25% of the time--no better than chance. The real surprise came when the researchers distracted the participants with anagram puzzles for 4 minutes before asking for their choices. More than half picked the best car. The counterintuitive conclusion, Dijksterhuis says, is that complex decisions are best made without conscious attention to the problem at hand.

They then left the laboratory to further test this result in a more ecological setting:

To test the idea in a more natural setting, the researchers visited two stores: the international furniture store IKEA and a department store called Bijenkorf. A pilot study with volunteer subjects had suggested that shoppers weigh more attributes when buying furniture than when buying kitchen accessories and other simple products commonly purchased at Bijenkorf. The researchers quizzed shoppers at the two stores about how much time they'd spent thinking about their purchases and then called them a few weeks later to gauge their satisfaction. Bijenkorf shoppers who spent more time consciously deliberating their choices were more pleased with their purchases--evidence that conscious thought is good for simple decisions, Dijksterhuis says. But at IKEA, the reverse was true: Those who reported spending less time deliberating turned out to be the happiest.

Of course, these results square well with a host of other recent neuroeconomic experiments which have found that decision-making is not only a matter of pain-staking cognitive deliberations, but also involves automatic and unconscious emotional biases. Yet, I’m beginning to wonder if we are not now in a position where we need more experimental attention to the interplay of emotions and cognition.

[2] In forthcoming issue of NeuroImage there will appear a new neuromarketing study by a German team that suggest that brand knowledge is computed by parts of the prefrontal cortex. Here’s the abstract:

Brands have a high impact on people's economic decisions. People may prefer products of brands even among almost identical products. Brands can be defined as cultural-based symbols, which promise certain advantages of a product. Recent studies suggest that the prefrontal cortex may be crucial for the processing of brand knowledge. The aim of this study was to examine the neural correlates of culturally based brands. We confronted subjects with logos of car manufactures during an fMRI session and instructed them to imagine and use a car of these companies. As a control condition, we used graphically comparable logos of car manufacturers that were unfamiliar to the culture of the subjects participating in this study. If they did not know the logo of the brand, they were told to imagine and use a generic car. Results showed activation of a single region in the medial prefrontal cortex related to the logos of the culturally familiar brands. We discuss the results as self-relevant processing induced by the imagined use of cars of familiar brands and suggest that the prefrontal cortex plays a crucial role for processing culturally based brands.

Again, if you have paid attention to the now rather huge literature on preferences, you will not be overly surprised by this result, although we may wonder why the Neuron brand study I mentioned last week found activation in lateral parts of the PFC, and this study activation in the medial parts. Two things, however. (1) First, a lot of studies are pointing to the medial OFC, or orbitofrontal cortex, as the locus of utility tracking, or the seat of the brain’s overall preference system. But what is this section of the brain actually doing. (2) What does the brain’s preference system more precisely have to do with brands? Is “a brand” just certain emotional response to some product or person? If so, how are such emotional preferences build?

[3] Finally, let me point you to a new review of the current status of the field of neuroeconomics which are set to appear in the next issue of Trends in Cognitive Science. The in press version can be found here. The authors are Alan Sanfey, George Loewenstein, Samuel McClure and Jon Cohen, four of the leaders of the field.


References

Dijksterhuis, A. et al. (2006): On Making the Right Choice: The Deliberation-Without-Attention Effect. Science 311: 1005-1007.

Schaefer, M. et al. (In press): Neural correlates of culturally familiar brands of car manufacturers. NeuroImage, to appear.

Sanfey, A. et al. (In press): Neuroeconomics: cross-currents in research on decision-making. Trends in Cognitive Science, to appear.

Tuesday, February 14, 2006

Incidental findings in fMRI

Judy Illes, director of the Program in Neuroethics at the Stanford Center for Biomedical Ethics, has a new paper out in last Friday's Science. Co-written with a large number of researchers, working with brain imaging techniques, the paper highlights the ethical issues raised by incidental findings in such studies. The basic problem is that, although a subject may appear healthy, and feel healthy, structural MRI's and other types of imaging data may yet divulge unexpected brain abnormalities. It is something all non-clinical experiments from time to time are certain to experience - I have myself - and we therefore need a policy for dealing with such findings, especially since many PET and fMRI experiments these days are conducted by investigators who are not medically trained.

Also, we should bear in mind that what today is solely a question of incidental clinical findings may in the future expand to many other, non-clinical areas. You volunteer to partcipate in a language study, and your scanning data turn out to indicate that you have paedophelic tendencies. Should this finding be reported or not?


Reference

Illes, J. et al. (2006): Incidental findings in brain imaging research. Science 311: 783-784.

Monday, February 13, 2006

Neuromarketing

For some years now the marketing industry has been intrigued by the possiblity of using brain science to get a handle on people's secret desires. Using brain scanners, the hope is to perfect the marketing of products by learning which presentations trigger the brain's "cool" or "must buy" buttons. The always great magazine Wired ran a story in its October 2004 issue on the neuromarketing research by Steven Quartz with the superb title "If you secretly like Michael Bolton, we'll know". (Quartz, by the way, is rumored to have a book out this year explaining "the neurobiology of cool".) Still, personally I only know of one real neuromarketing study, namely the well-known Neuron-study conducted by the Montague group which investigated how knowing the brand of two different cola products influences their consumption. (Quartz is one of the co-authors of this study, but hasn't published anything else on the subject in peer-refereed journals.)

Now, in connection with the American super bowl, Marco Iacoboni has conducted an "instant-science experiment" where he and his colleagues imaged 5 subjects in an fMRI scanner while they watched the ads run during the breaks in the game. He then published a preliminary report on the www.edge.org website which has prompted a slush of comments. The New York Times referenced Iacobon's short article, and a number of bloggers have made their thoughts public in the days since. See for instance the Neuromarketing blog's positive reaction here, and then compared it to the Mind Hack guys' much more negative reaction here.

For my own money, I find the general idea of investigating the neural machinery that make us react in one way or another to ads and products both highly interesting and very important. (It is an important aspect of out lifes.) I don't feel, however, that any neuromarketing experiment at the moment will be able to tell an ad agency anything really important. Our knowledge of how the brain's preference system works is simply to rudimentary. The way Iacoboni claims he can see activity in his subjects' brains which are at odds with their overt reports must be treated with the utmost skepsis. Even if some ad actually elicits a high response in the reward system this activity may not, simply, correlate with a clear-cut preference for the ad. The reason is that the reward system is composed of several different structures which may interact and compete for the final verdict. (This is something I myself often see in my own research on aesthetic preferences for works of art.) Iacoboni, an expert of mirror neurons, also speculates that one ad, which very strongly activated the premotor region, might be the most "succesful" ad. But how does he know that the mirror neurons located in this region even play an important role in the formation of preferences? This is certainly news to me. It may well be true, as he writes, that mirror neurons activity underlies some sort of empathy with the persons depincted in the perceived ads, but I have never seen any experimental evidence linking empathy to preference. We might well prefer persons we empathize with, but nobody has, as of yet, demonstrated that we do so, to my knowledge at least.

As important as this research is in principle, we should be careful not to get over-excited about single studies that claim a lot. Especially if they are based on group analyses involving data from only 5 subjects! We should go forward with research on neuromarketing, but at the same time remember that there is a long way to go.

Thursday, February 09, 2006

Brainy politicians

Here's a new field of scientific enquiry: Political Biology, or biopolitics. It sounds strange, doesn't it? To me, it sounds most like politicians trying to influence how research should be conducted, which areas should be allowable and which should not.

But it's actually the reverse: as this page attests, biopolitics is about how politics could and should be influenced by scientific advances in biology (and, as a consequence, neuroscience). My only - yet substantial - concern is that this approach seems to stop at "biology", especially evolutionary theory. It most likely includes evolutionary psychology, but even within EP, we rarely if ever see proper discussions about how brain science can inform psychological theories. As this previous note from Martin shows, neuroscience CAN indeed say meaningful things to cognitive and evolutionary psychological theory. So the concern with biopolitics is that it will not include the full range of scientific results in this rapidly developing field.

From that very site, it says;

In their classic formulations, valid to this day, the issue of self-preservation is foundational for both political science and economics. In order to fixate this concept, the Modern theorists relied upon various assumptions about human nature. Due to the advances of biology and evolutionary theory, we are today in the position of explicating these assumptions in the form of stable scientific certainties. A foundational concept in biological theory is that of "fitness". The paper indicates the relationship between the less determined concept of self-preservation and the more rigorous one of fitness. By that, it accomplishes two things: it gives more solidity to the foundation of political theory and political economy, by anchoring them in biology; it opens the path towards a unification between two social sciences and their immediate juxtaposed science, biology. The emphasis of the paper is on political science, aiming to define, on the basis of the above argument, its proper object of study. The notion of fitness extraction is thus defined. A lateral exposition differentiates between political action, thus understood, and economic action, defined more generally as fitness transfer. The distinction is to be eventually furthered in a separate study.

Nalmafene for your ludomania

I have mentioned this as a headline at SCR. A new study demonstrates that Nalmefene, an experimental drug, has positive treatment effects on compulsive gambling. It works through making gambling become less thrilling and compelling. Maybe we can soon find a drug that makes statistics lectures more exciting, too?
__________________________________________

Multicenter investigation of the opioid antagonist nalmefene in the treatment of pathological gambling.

by Grant et al. in Am J Psychiatry. 2006 Feb ; 163(2): 303-12

OBJECTIVE: Pathological gambling is a disabling disorder experienced by approximately 1%-2% of adults and for which there are few empirically validated treatments. The authors examined the efficacy and tolerability of the opioid antagonist nalmefene in the treatment of adults with pathological gambling.

METHOD: A 16-week, randomized, dose-ranging, double-blind, placebo-controlled trial was conducted at 15 outpatient treatment centers across the United States between March 2002 and April 2003. Two hundred seven persons with DSM-IV pathological gambling were randomly assigned to receive nalmefene (25 mg/day, 50 mg/day, or 100 mg/day) or placebo. Scores on the primary outcome measure (Yale-Brown Obsessive Compulsive Scale Modified for Pathological Gambling) were analyzed by using a linear mixed-effects model.

RESULTS: Estimated regression coefficients showed that the 25 mg/day and 50 mg/day nalmefene groups had significantly different scores on the Yale-Brown Obsessive Compulsive Scale Modified for Pathological Gambling, compared to the placebo group. A total of 59.2% of the subjects who received 25 mg/day of nalmefene were rated as "much improved" or "very much improved" at the last evaluation, compared to 34.0% of those who received placebo. Adverse experiences included nausea, dizziness, and insomnia.

CONCLUSIONS: Subjects who received nalmefene had a statistically significant reduction in severity of pathological gambling. Low-dose nalmefene (25 mg/day) appeared efficacious and was associated with few adverse events. Higher doses (50 mg/day and 100 mg/day) resulted in intolerable side effects.

HubMed (cache)

______________________________________

See also this story in The Nation

Drug Shows Promise in Curbing Compulsive Gambling, Study Says

By Robert Lee Hotz in The Nation

For the estimated 6 million compulsive gamblers in the U.S., the long odds are on a pill.

In the largest clinical study of its kind, researchers at the University of Minnesota found that daily doses of an experimental drug called nalmefene, often used to treat alcoholism, appeared to curb the craving to gamble.

ADVERTISEMENT

The research represents the latest effort to control the biology of misbehavior at a time when celebrity poker, online gambling, lotteries and sports betting have helped to make obsessive wagering a national psychiatric disorder.

"The study is part of emerging evidence that gambling, once thought to be a problem in moral integrity, is instead a problem in brain biology and can be successfully treated," said Dr. Robert Freedman, editor of the American Journal of Psychiatry, which published the study today in its February issue.

(...)

The Nation

Tuesday, February 07, 2006

Self and personality stability in ageing

A recent meta-analysis by Roberts, Walton and Viechtbauer published in Psychological Bulletin demonstrate that personality traits change over time. Some things that change over time includes our social interactions, they find, as well as our emotional stability. It would be most interesting to see how these findings relate to our normal sense of self, i.e. our feeling that we are the same person over time.

Here is the abstract:

Patterns of mean-level change in personality traits across the life course: a meta-analysis of longitudinal studies.

Roberts BW, Walton KE, Viechtbauer W in Psychol Bull. 2006 Jan ; 132(1): 1-25

The present study used meta-analytic techniques (number of samples = 92) to determine the patterns of mean-level change in personality traits across the life course. Results showed that people increase in measures of social dominance (a facet of extraversion), conscientiousness, and emotional stability, especially in young adulthood (age 20 to 40). In contrast, people increase on measures of social vitality (a 2nd facet of extraversion) and openness in adolescence but then decrease in both of these domains in old age. Agreeableness changed only in old age. Of the 6 trait categories, 4 demonstrated significant change in middle and old age. Gender and attrition had minimal effects on change, whereas longer studies and studies based on younger cohorts showed greater change. ((c) 2006 APA, all rights reserved).

HubMed

Brent Robert homepage

Monday, February 06, 2006

Mind Wars!

In the wake of my post yesterday about US government attempts to build a workable lie detector for use in the war on terror, here is an article about Jonathan Moreno, bioethics adviser for the Howard Hughes Medical Institute, who has a book coming out later this year entitled Mind Wars: National Security and the Brain. A little teaser from the article:

One of the leaders in neuroscience development is the corporation DARPA, which is currently in the process of developing a "head web," a helmet that conducts non-invasive brain monitoring that could be used to measure brain waves while soldiers are in combat. Moreno said the government is also working on developing a "war fighter"-a human manipulated by drugs to be a more efficient soldier. The "war fighter" would require less sleep, less protein and could heal itself with the aid of drugs and technology. The war fighters would eventually be replaced by robots, which would be controlled by human soldiers in a bunker somewhere out of harm's way. "We are probably moving to a cyborg technology," Moreno said, and one of the first steps toward a more robotic world is the use of neurologically manipulative drugs, like the "anti-conscience pill," which can treat stress, reduce guilt and potentially eliminate entire memories, preventing psychological conditions like post-traumatic stress disorder.

Says Moreno:

"I don't think the government will control our brains in the old-fashioned, 'Manchurian Candidate' sense, but we will eventually be able to change our brains."

I found the link to the article at the excellent Neuromarketing Blog.

Imaging Genetics 2006

It has taken me some time to digest the impressions from the 1½ day International Imaging Genetics conference held in Irvine a couple of weeks ago. This is probably because it was hard to sort the different issues out initially. The conference had speakers from genetics, statistics and neuroimaging.

Correspondingly, there were three major Imaging Genetics (IG) themes one can sort this conference into: genetics methods, statistical approaches and visualisations, and neuroimaging related issues.

IG Statistics
Doing statistics is a humbling experience, and the IG conference was a wonderful reminder of this. In the burgeoning field of IG, many studies that have been published in top rated journals would probably not even make it past the editor today. On the other hand, it's only been a few years since one could get an article published in Nature or Science because you found some signal in the brain during a cognitive task. Anyway, the statistics were no exception to all the demonstrations associated with doing statistics, although it came with a twist. Since IG is a combination of at least two approaches - genetics and neuroimaging - each study must seek to accommodate to the pitfalls and premises of both approaches. This is not a simple task: neuroimaging contains a multitude of different statistical approaches, in addition to an overwhelming number of issues and pitfalls when it comes to the design, collection and preparation (i.e. preprocessing) stages in a study. I can only guess that the same goes for genetics.

During lunch, I heard a geneticist asking "What is a voxel? Is it like a pixel?". So IG has a long way to go in order to reach a full, common understanding and sharing of ideas, concepts and methods. I'm certainly asking just the same kind of beginner's questions about genetics. So when Bernie Devlin said about the speaker before him, Tom Nichols, "I am glad that Tom says he does not know much about genetics. I can assure you - he doesn't!" he was making this very point.

But the IG statistics also had some very interesting and directly useful aspects. Nik Schork talked about different ways to visualise and analyse IG data, and demonstrated a most impressive toolbox of different methods for doing so. Unfortunately, I can't find any illustrations online (nor in any article) to show this. I'll get back with as soon as something comes up. See also this video of one of his talks.

Genetics
This part was probably the hardest, since so much relied on one's knowledge about genetics. Haplotype, SNPs, alleles and so on, just to mention a few. If you have not heard about this before, you're not alone. But even knowing about these keywords and concepts, bringing them together with neuroimaging really poses a test of your working memory ability... I'll expose my lack of understanding of these issues here,yet still mention the hapmap project and its tremendous usefulness in assessing the distribution of haplotypes in different populations. Not directly viable when doing neuroimaging studies, but it can influence the likelihood that you choose to study one haplotype rather than others.

Neuroimaging
This is by far the easiest part of the conference, at least to me, and I guess geneticists had the harder time in this part of the conference. However, one can also see that the neuroimaging studies that were presented here really demonstrated the end results of the tedious work that had been presented in the foregoing talks. Since neither the basics of neuroimaging signals, stats or pitfalls were presented as such, researchers from other - non-neuroimaging - approaches probably had an easier time than us genetics-nogoods had previously...

Basically, one could say that IG brings a new tool to look at what drives your neuroimaging data, even in healthy individuals. Studies by researchers as Ahmad Hariri, Dan Wainberger and Andreas Meyer-Lindenberg illustrates this point clearly. Their studies have now demonstrated that a natural variation in specific alleles produce different responses in not only the brains of the different subjects, but even how behaviour is affected. This includes a study of how long and short versions of a seretonin transporter gene affects brain regions affected in depression. It can also demonstrate how genes affect the brain to produce a higher risk of developing schizophrenia, or how a gene influences brain size. It can also be used to enhance our understanding of different cognitive functions, such as attentional networks, in the brain.

For last year's conference you can now download video recordings and the slideshows of the talks from the Irvine IG conference homepage. I suspect that the talks for this year will be available soon, too.

Mixing Teeth of the Memory Mind

Just found this interesting blog called Mixing Memory. From the blog you can read:

The Intellectual Teeth of the Mind

Early one morning earlier this week, I received an email about a radio program in Massachusets called Radio Open Source, which aired a program that evening on TheEdge.org's question, "What is your dangerous idea?" (I believe you can listen to the program at any time by following that link). I'm sure some of you who commented on the question received an email as well (Razib was even quoted on the show). The email mentioned that they were going to be interviewing Steven Pinker and others. So while I was sitting around doing some work, I listened to the program. It was actually pretty interesting. The "others" included Jesse Bering, Daniel Dennett, and Steven Strogatz. I'll try to get to Berring's answer, and his work (which is interesting as well) in a future post, but for now, I want to concentrate on something that the answers given by Dennett and Strogatz reminded me of. If you recall, Dennett's answer to TheEdge.org's question was about memes (big surprise). He said, in essence, that our minds are being inundated with memes, and pretty soon, if it isn't the case already, there will be more memes than we can handle. Strogatz' answer is related, though in a non-obvious way, perhaps.

Sunday, February 05, 2006

The neuroscience of lying

Lying seems to be the topic of the day. In the last month alone two popular articles have appeared covering recent attempts to unveil the brain signatures of lying. The first came out in the January issue of Wired. (You may find the electronic version here.) And today the NY Times Magazine follow up with their take on the story. Go read it here.

Both articles basically report the same story. Aftet 9/11 the American government has become highly interested in procuring a sure-fire method of spotting liers. The American military has a whole department, the Department of Defense Polygraph Institute (DODpi), working exclusively on inventing an easy-to-use device that in the future will be able to tell apart lies from the truth. Clearly such a device will have to be based on the ability to identify physical tell-tale signs that a person is lying. And to do so, DODpi will have to know the neural cause of lying. Reportedly more than 50 American labs are currently working on identifying these brain processes.

Not much, however, is known about the neurocognitive mechanisms underlying lying. Chances are that lying cannot be associated with just one "lie-module". When lying you must be able to distinguish the lie from the truth; you will probably have to activate your ToM-system in order to organize your lie in accordance with what you think the other person knows and wants to hear; in some situations you have to remember what you have previously told other persons; you certainly have to plan ahead; and most probably you will have to control your emotional system. These cognitive mechanisms all rely on numerous neural processes.

So, what to do about structures that show up on statistical parametric maps in fMRI experiments? Dan Langleben - the first researcher to study lying with fMRI - have demonstrated that making a lie is associated with elevated activity in the anterior cingulate cortex. Yet, as I have previously noted in a post on this blog, the precise function of the ACC is still unclear. Thus, it may be the case that even though lying is associated with ACC activity, not all activity in the ACC is associated with lying! This opacity of the brain raises serious ethical questions, because will a DODpi-device made to detect ACC activity label some people liars who are not really lying? And will it, coversely, neglect liars who are lying using other neurocognitive mechanisms than just the ACC? These questions pose a serious challenge to the race for a neuroscience-based lie detector.

Another, more profound, ethical questions that this reserach raises is the following: do we really want to live in world without lying? Generally, lying is frowned upon. Yet, imagine if you had to tell the truth all the time. It is not only lawyers, such as the character Jim Carey plays in Liar Liar, that benefit from our ability to conceil our innermost thoughts and deceive. Lying plays an enormous role in human social life, some for bad, but some also for good. If lie detection devices should become succesful we will have to discuss when and where to use them. In the class room, at a job interview, in the minister's office when we get married?

References

Langleben, D. et al. (2002): Brain activity during simulated deception: An event-related functional magnetic resonance study (PDF file). Neuroimage 15: 727-732.

Silberman, S. (2006): Don't even think about lying. Wired 14.01.

Henig, R.M. (2006): Looking for the lie. New York Times Magazine. February 5, 2006.

Saturday, February 04, 2006

Sex and Money: Neurofinance

One of the most exiting new fields of neuroscience is neuroeconomics. As the name indicate, this field investigates the decision-making processes that underlie economic behaviour. As was to be expected neuroeconomics is now spawning a off-spring called neurofinance. Why are some investors better at making money than others? The first neurofinance study, using brain imaging, was published in the September 1 issue of Neuron. Here's the authors abstract:

Investors systematically deviate from rationality when making financial decisions, yet the mechanisms responsible for these deviations have not been identified. Using event-related fMRI, we examined whether anticipatory neural activity would predict optimal and suboptimal choices in a financial decision-making task. We characterized two types of deviations from the optimal investment strategy of a rational risk-neutral agent as risk-seeking mistakes and risk-aversion mistakes. Nucleus accumbens activation preceded risky choices as well as risk-seeking mistakes, while anterior insula activation preceded riskless choices as well as risk-aversion mistakes. These findings suggest that distinct neural circuits linked to anticipatory affect promote different types of financial choices and indicate that excessive activation of these circuits may lead to investing mistakes. Thus, consideration of anticipatory neural mechanisms may add predictive power to the rational actor model of economic decision making.

If you wish to prepare yourself for the reading of Camelia Kuhnen and Brian Knutson's paper go to Bloomberg.com here where you will find a nice journalistic take on the whole neurofinance phenomenon. It can more or less be summed up in the statement from Daniel Kahneman, quoted in the article:

"The brain scientists are the wave of the future in the financial world".


Indeed!


References

Kuhnen, C. & Knutson, B. (2005): The neural basis of financial risk taking. Neuron 47: 763-770.

Levy, A. (2006): Brain scans show link between lust for sex and money. Bloomberg.com. February 1.