This is scary....Americans at bottom of list in belief in evolution.

From the Science Magazine Policy Forum note by Miller et al.

"Over the past 20 years, the percentage of U.S. adults accepting the idea of evolution has declined from 45% to 40% and the percentage of adults overtly rejecting evolution declined from 48% to 39%. The percentage of adults who were not sure about evolution increased from 7% in 1985 to 21% in 2005...Regardless of the form of the question, one in three American adults firmly rejects the concept of evolution, a significantly higher proportion than found in any western European country...the structure and beliefs of American fundamentalism historically differ from those of mainstream Protestantism in both the United States and Europe. The biblical literalist focus of fundamentalism in the United States sees Genesis as a true and accurate account of the creation of human life that supersedes any scientific finding or interpretation. In contrast, mainstream Protestant faiths in Europe (and their U.S. counterparts) have viewed Genesis as metaphorical and--like the Catholic Church--have not seen a major contradiction between their faith and the work of Darwin and other scientists...the evolution issue has been politicized and incorporated into the current partisan division in the United States in a manner never seen in Europe or Japan. In the second half of the 20th century, the conservative wing of the Republican Party has adopted creationism as a part of a platform designed to consolidate their support in southern and Midwestern states--the "red" states. In the 1990s, the state Republican platforms in seven states included explicit demands for the teaching of "creation science". There is no major political party in Europe or Japan that uses opposition to evolution as a part of its political platform...The broad public acceptance of the benefits of science and technology in the second half of the 20th century allowed science to develop a nonpartisan identification that largely protected it from overt partisanship. That era appears to have closed."

Remembrance of mild moments past: add a little arousal

A recent McGaugh review in Trends in Cognitive Science (Volume 10, Issue 8 , August 2006, Pages 345-347) discusses a PNAS paper by Anderson and colleagues demonstrating that emotionally arousing stimuli enhance long-term memory of immediately preceding neutral stimuli. This fits with with extensive evidence from both human and animal studies indicating that arousal-induced modulation of memory is mediated by β-noradrenergic activation of the amygdala.

(By the way, in my July 20 post on involvement of the Locus Ceruleus in the retrieval of emotional memories I inexplicably neglected to mention that this cluster of nerve cells in the lower brain synthesizes noradrenaline (norepinephrine). Its axons, which project to the amygdala and other cortical areas, can 'spritz' large areas of the cortex during arousal, to enhance both the storage and retrieval of emotional memories.)

McGaugh gives a simplified graphic to summarize the main idea:


Figure - Schematic representation of modulation of memory consolidation by emotional arousal-induced release of adrenal stress hormones and noradrenergic activation of the amygdala. Emotional arousal activates the release of noradrenaline in the basolateral amygdala as well as the release of adrenal stress hormones. The stress hormones then provide increased and sustained noradrenergic activation in the amygdala. The amygdala activation modulates memory consolidation via projections to other brain systems processing memory. (Credit TICS)

The Universe in a Neuron, and vice versa

I wanted to pass on the graphics that appeared in this morning's science section of the New York Times. The images show the surprisingly similar patterns seen in vastly different natural phenomena: a neuron (micrometers wide) and the universe (billions of light-years across). The neuron image is from Mark Miller at Brandeis Univ. and the universe image from a consortium of astrophysicists

Neuron

















Universe

Complex Choices Better Made Unconsciously? A critical exchange...

I thought it worth reproducing a current exchange in Science Magazine:

In their Report "On making the right choice: The deliberation-without-attention effect" (17 Feb., p. 1005), A. Dijksterhuis and colleagues reported the intriguing finding that when participants had to choose among four cars on the basis of various attributes, a period of conscious reflection worsened performance. They took this as evidence that complex choices are better when made unconsciously. A close examination of their methods, however, suggests a less startling interpretation.

Because of the easily confusable statements about the four cars, the 4-min period of reflection would cause considerable memory interference and leave participants utterly confused (was it the Hatsdun that had good handling and the Kaiwa no cupholders, or the other way round?). Memory research in the Bartlettian tradition has revealed many examples of such self-generated interference (1). The unconscious group made their decision after a similar 4-min period filled with a distractor task. Knowing that they would have no further opportunity for reflection prior to being required to make their choice, these individuals probably just made their decision at the end of the study period based on their overall impression of which car was best. This alternative account makes a simple and testable prediction, namely, that memory recall will be worse in the conscious condition.

An interesting but unnoted aspect of the findings was that the deliberation group chose the best car on only about 25% of occasions, exactly at chance. Does conscious deliberation yield no more than random results? The alternative account suggested here offers an explanation: It must have been because these individuals were faced with an insurmountable memory challenge and were completely confused about which attributes went with which car.

In any event, the decision problem presented in this study is very unlike the way we normally deliberate about a problem. When choosing between cars, we don't expend effort struggling to recall their attributes; we familiarize ourselves with the relevant attributes during the information search stage, and if we can't recall some attribute, we find it out. Dijksterhuis et al.'s findings would be altogether more compelling if they were replicated in a situation in which the 4-min deliberation period was spent studying the cars' attributes. But the likelihood is that under such circumstances, the best alternative would be selected by close to 100% of participants.

Reference 1. H. L. Roediger, E. T. Bergman, M. L. Meade, in Bartlett, Cognition and Culture, A. Saito, Ed. (Routledge, London, 2000), pp. 115-134.

David R. Shanks
Department of Psychology
University College London
Gower Street
London WC1E 6BT, UK

Response
In our work on the "Deliberation-without-attention" effect, we found that, under complex decision circumstances, unconscious thinkers made better decisions than conscious deliberators. Conscious deliberators suffer from the low memory capacity of consciousness, which renders it impossible for them to take into account substantial amounts of information simultaneously. Unconscious thinkers, on the other hand, are not negatively affected by such capacity constraints. Shanks offers alternative explanations for our findings for both conscious deliberators and unconscious thinkers.

Shanks argues that our conscious thinkers may have faced memory problems. However, memory problems are not causing the effects we see. We have shown that even when the statements are presented in blocks (i.e., first all information on car A, then on car B, etc.), conscious deliberation still produces poor results (1). In addition, we have shown that even when people do have all the information at hand during conscious deliberation, it still produces poor results (2).

Shanks's suggestion that unconscious thinkers simply stick to the initial decision they made immediately after processing the information is not correct. In other experiments (1-3), we have compared unconscious thinkers with people who made decisions immediately after having received all the information, and unconscious thinkers performed better. Unconscious thought does lead to changes in preference, and it does so for the better.

Shanks also notes that under complex conditions, decisions made by conscious deliberators are no better than chance. Although conscious deliberation itself cannot be said to be random, the decisions produced by conscious deliberation are under some circumstances not superior to randomly generated decisions. There are moderators at work here, of course (e.g., expertise). Thus, the idea that conscious deliberation before making decisions is always good is simply one of those illusions consciousness creates for us.

Finally, Shanks observed that our experiments do not reflect the way people normally make decisions. This is true, as is usually the case with lab experiments. However, that is exactly the reason we included two field studies in our Report. In the field studies, people made real decisions with real consequences. These studies also confirmed the "deliberation-without-attention" hypothesis.

References 1. A. Dijksterhuis, J. Pers. Soc. Psychol. 87, 586 (2004). 2. A. Dijksterhuis, Z. van Olden, J. Exp. Soc. Psychol., in press. 3. A. Dijksterhuis, L. F. Nordgren, Pers. Psychol. Sci. 1, 95 (2006).

Ap Dijksterhuis
Maarten W. Bos
Loran F. Nordgren
Rick B. van Baaren
Department of Psychology
University of Amsterdam
Roetersstraat 15, 1018 WB
Amsterdam, the Netherlands

"Hare Brain, Tortoise Mind" and "The Wayward Mind"

These are the titles of two books by British psychologist Guy Claxton (see his website) that I think have received less attention than they should. (It seems to me that British and American psychologists group themselves in quite separate worlds.) The first book is a lucid presentation of experimental work that supports Herbert Spenser's dictum "The determined effort causes perversion of thought." Claxton uses the term "undermind" to describe intuitive and integrative processes normally beyond the range of, and can be inhibited by, our focused awareness. Extremes of being indiscriminately intuitive or insisting on lots of high-quality information can block results.

The term 'undermind' hasn't caught on, and the subsequent excellent book "The Wayward Mind" reverts to using the term "unconscious". "The Wayward Mind" is a history of human attempts to explain the unconscious mind, from ancient descriptions of the 'underworld' to the theories of modern neuroscience.

Here are (clipped and truncated) some lines from pp 348-352 of "Wayward Mind" that I like:
"What we call our ‘self’ is an agglomeration of both conscious and unconscious ingredients: cans, needs, dos, oughts, thinks….these constructions hold out an overwhelming temptation: to assume that the “I” is the same in all of them… so that instead of having an intricate web of things that make me Me, I have to create a single imaginary hub around which they all revolve, to which they all refer…the attempt to keep this fiction going, to ‘hold it together’ can become quite tiring and bothersome… If “I” am essentially reasonable, if I imagine that my zones of control – over my own feelings for example – are wider and more robust than they are, then I am going to get in a tangle trying to ‘control myself.’ If I have decided that who I am is clever, attractive, athletic, stable, creating the hub of “I” locks everything together and prevents it moving. It stops Me expanding to include the unconscious, or graciously shrinking to accommodate old age. I can’t enjoy my waywardness, nor see it as an intrinsic part of ME….All the evidence is that a more relaxed attitude toward the bounds of self makes for a richer, easier and more creative life. Perhaps, after all, waywardness in all its forms is in need not so much of explanation, but of a mystified but friendly welcome. We can explain it if we wish, and the brain is beginning to a reasonable job. But the need to explain, when not motivated by the dispassionate curiosity of the scientist, is surely a sign of anxiety: of the desire to tame with words that which is experienced as unsettling.. "

Do pheromone receptors in our nose pick up subliminal signals?

Mouse urine contains compounds, termed pheromones, that can alter the social or sexual behaviour of other mice. They bind to receptors a structure in the mouse nose called the vomeronasal organ. This organ is thought to be vestigial and defunct In humans, and the role of pheromones in human behavior is debated (which hasn't stopped biotec companies from selling perfumes purported to be human male or female sex attractants..... my personal trial of same did not significantly increase the rate of amorous attacks on my person from its baseline rate of zero, although I imagined that my cat might be acting a bit more affectionate). A review by Pierson (Nature 442, 495, 3 August 2006) notes "most evidence for human pheromones has come from behavioural research. In one study, scientists at the University of Chicago showed that women's menstrual cycles changed in length after they sniffed the sweat on pads previously worn in the armpits of another woman (K. Stern & M. K. McClintock Nature 392, 177–179; 1998). Another study showed that newborn babies move towards a pad carrying the smell of their mother's breast rather than a clean pad (H. Varendi & R. H. Porter Acta Paediatr. 90, 372–375; 2001).

At any rate, a report from Buck's laboratory (Nature 442, 645-650,10 August 2006) now finds mouse pheromone receptors in the lining of the nose, rather than the vomeronasal organ, and genes encoding this family of receptors are found also in humans and fish.

Figure legend: Digoxigenin-labelled antisense RNA probes for the mouse Taar genes indicated were hybridized to coronal sections of mouse olfactory epithelium. Each Taar probe hybridized to mRNA in a small percentage of OSNs scattered in selected olfactory epithelial regions. Credit: Nature Magazine

From the abstract: "these receptors, called 'trace amine-associated receptors' (TAARs), ... like odorant receptors... are expressed in unique subsets of neurons dispersed in the epithelium... at least three mouse TAARs recognize volatile amines found in urine: one detects a compound linked to stress, whereas the other two detect compounds enriched in male versus female urine—one of which is reportedly a pheromone. The evolutionary conservation of the TAAR family suggests a chemosensory function distinct from odorant receptors. Ligands identified for TAARs thus far suggest a function associated with the detection of social cues."

It remains to be seen whether activating or eliminating any of these TAAR receptors alters mouse behavior, and this needs to be demonstrated before moving on to possible human studies.

Another volume on flaws of the intelligent design argument, political setbacks to its advocates.

The Princeton evolutionary biologist John Tyler Bonner writes a review in a recent issue of Nature of the Volume "Intelligent Thought" edited by John Brockman. A series of essays demolish intelligent design theory from a number of directions. The bottom line is that intelligent design is not science because it is not falsifiable.

In some ways it is like shooting fish in a barrel. When giving his decision at the trial in which the school board in Dover, Pennsylvania, was challenged for including intelligent design in the biology curriculum (see Nature 439, 6–7;2006), federal judge John Jones described the argument that intelligent design is science as a "breathtaking inanity". His ruling is reprinted in part at the end of the book.

A recent election in Kansas has returned control of the State Board of Education to moderates who plan to reverse the redefinition of science attempted by the previous conservative board. Intelligent design advocates also have recently received setbacks in Ohio and Pennsylvania, but will certainly not give up their crusade.

An animal model for abusive attachment.

There is an interesting brief communication by Moriceau and Sullivan in Nature Neuroscience (vol. 9, pp. 1004 - 1006, 2006) describing how maternal presence can switch fear learning to attraction in preweanling (12–15 days old) rats. In the mother's absence, odor-shock conditioning produces amygdala activation and learned odor avoidance. With maternal presence, this same conditioning yields an odor preference without amygdala activation. Maternal presence acts through suppressing pup corticosterone and thus corticosterone's regulation of amygdala activity. Intra-amygdala corticosterone infusions that over-ride maternal suppression of corticosterone permit fear conditioning and amygdala activation to return.

The data suggest that preweanling pups have two odor-shock learning circuits, with maternal presence providing suppression of stress-induced corticosterone release and engaging the odor-shock circuit for odor preference learning supporting infant-mother attachment. The data suggest a way in which the functional maturation of brain development may be disrupted by stress.. The mother's ability to modify fear learning circuitry may provide clues to abusive attachment and predisposition for mental illness and altered emotional expression later in life. The validity of an animal model of abusive attachment is strengthened by the wide phylogenetic representation of abusive attachment, which has been documented in chicks, infant dogs, rodents and nonhuman primates.

How emotions nudge rationality - brain correlates of "framing"

A very elegant report by Martino et al. from Dolan's laboratory has the title: "Frames, Biases, and Rational Decision-Making in the Human Brain"

"Human choices are remarkably susceptible to the manner in which options are presented. This so-called "framing effect" represents a striking violation of standard economic accounts of human rationality, although its underlying neurobiology is not understood. We found that the framing effect was specifically associated with amygdala activity, suggesting a key role for an emotional system in mediating decision biases. Moreover, across individuals, orbital and medial prefrontal cortex activity predicted a reduced susceptibility to the framing effect. This finding highlights the importance of incorporating emotional processes within models of human choice and suggests how the brain may modulate the effect of these biasing influences to approximate rationality."

From the brief review of this article by Miller in the same issue of Science, one example of framing:

Faced with a decision between two packages of ground beef, one labeled "80% lean," the other "20% fat," which would you choose? The meat is exactly the same, but most people would pick "80% lean." The language used to describe options often influences what people choose, a phenomenon behavioral economists call the framing effect. The Martino et al. experiments look directly at brain activity correlating with this effect.

The experiments used a novel financial decision-making task. Participants (20 university students or graduates) received a message indicating the amount of money that they would initially receive in that trial (e.g., "You receive £50"). Subjects then had to choose between a "sure" option and a "gamble" option presented in the context of two different frames. The "sure" option was formulated as either the amount of money retained from the initial starting amount (e.g., keep £20 of the £50; "Gain" frame) or as the amount of money lost from the initial amount (e.g., lose £30 of the £50; "Loss" frame). Subjects - who performed the task while inside an fMRI scanner! - were risk-averse in the Gain frame, tending to choose the sure option over the gamble option and were risk-seeking in the Loss frame, preferring the gamble option.

The amygdala (A, in the figure) was relatively more activated when subjects chose in accordance with the frame effect. When subjects made decisions that ran counter to their general behavioral tendency enhanced activity in the anterior cingulate cortex was observed (C, in the figure). This suggests an opponency between two neural systems, with ACC activation consistent with the detection of conflict between predominantly "analytic" response tendencies and a more "emotional" amygdala-based system.

Decreased susceptibility to the framing effect correlated with enhanced activity in the orbital and medial prefrontal cortex, specifically in the right orbitofrontal cortex (A, in the figure). The findings support a model in which the OMPFC evaluates and integrates emotional and cognitive information, thus underpinning more "rational" (i.e., description-invariant) behavior.

The framing bias occurs because "individuals incorporate a potentially broad range of additional emotional information into the decision process. In evolutionary terms, this mechanism may confer a strong advantage, because such contextual cues may carry useful, if not critical, information. Neglecting such information may ignore the subtle social cues that communicate elements of (possibly unconscious) knowledge that allow optimal decisions to be made in a variety of environments. However, in modern society, which contains many symbolic artifacts and where optimal decision-making often requires skills of abstraction and decontextualization, such mechanisms may render human choices irrational."

Cortical Plasticity and Recovery from Brain Injury

Ramanathan et al have made some interesting observations on the recovery of complex movement patterns after focal damage to the rat motor cortex. They used "behaviorally relevant," long-duration (500-msec) intracortical microstimulation of rat motor cortex that causes complex, multijoint movements. A consistent topographic distribution of these complex motor patterns is present across the motor cortex in naïve rats. They documented the plasticity of these complex movement patterns after focal cortical injury by measuring a significant expansion of specific complex movement representations in response to rehabilitative training after injury. (The rehabilitative training task required animals to use the forepaw to reach through a small slit in a Plexiglas chamber and grasp and retrieve a small food pellet positioned on a platform near the chamber.) The degree of functional recovery attained after cortical injury and rehabilitation correlated significantly with a specific feature of map reorganization, the ability to reexpress movement patterns disrupted by the initial injury. This suggests the existence of complex movement representations in the rat motor cortex that exhibit plasticity after injury and rehabilitation. Thus there is a significant correlation between the reorganization of disrupted complex representations and behavioral recovery after brain injury.

The graphic shows the types of complex movement elicited by long-duration microstimulation. The maps of motor cortex regulating these movements are a bit complex to show in this posting.

Figure: Complex movements elicited by long-duration microstimulation. (A–C) Three types of complex movements evoked by long-duration stimulation within motor cortex. Complex movements elicited by long-duration microstimulation occur across multiple joints. (A) Reaching movement characterized by rostral displacement of the elbow and shoulder, without change in wrist configuration. (B) Retraction characterized by caudal displacement of the elbow and forepaw. (C) Grasping movement characterized by contraction of all digit joints simultaneously. Credit: PNAS.

My Evil Twin Posted This

I couldn't resist.

Social Class and Values - an inversion?

A humorous Op-Ed piece in the Aug 3 NYTimes by David Brooks notes a recent trend in America that he considers a blow to the natural order of the universe. "In all healthy societies, the middle-class people have wholesome middle-class values while the upper-crust bluebloods lead lives of cosseted leisure interrupted by infidelity, overdoses and hunting accidents. But in America today we’ve got this all bollixed up... Through some screw-up in the moral superstructure, we now have a plutocratic upper class infused with the staid industriousness of Ben Franklin, while we are apparently seeing the emergence of a Wal-Mart leisure class — devil-may-care middle-age slackers who live off home-equity loans and disability payments so they can surf the History Channel and enjoy fantasy football leagues...For the first time in human history, the rich work longer hours than the proletariat"...(the piece then documents a number of middle aged men who have dropped out of the work force).. "What I see is a migration of values. Once upon a time, middle-class men would have defined their dignity by their ability to work hard, provide for their family and live as self-reliant members of society. But these fellows, to judge by their quotations, define their dignity the same way the subjects of Thorstein Veblen’s “The Theory of the Leisure Class” defined theirs... by the loftiness of their thinking. They define their dignity not by their achievement, but by their personal enlightenment, their autonomy, by their distance from anything dishonorably menial or compulsory."

And, in a bit of a non-sequitur: "The only comfort I’ve had from these disturbing trends is another recent story in The Times. Joyce Wadler reported that women in places like the Hamptons are still bedding down with the hired help. R. Couri Hay, the society editor of Hamptons magazine, celebrated rich women’s tendency to sleep with their home renovators..."Nobody knows,” he said. “The contractor isn’t going to tell because the husband is writing the check, the wife isn’t going to tell, and you get a better job because she’s providing a fringe benefit. Everybody wins.”...Thank God somebody is standing up for traditional morality."

The Gender Wars Continuing - retort from Pinker

Here is the latest exchange between Steven Pinker and his detractors, from the Aug 3 issue of Nature Magazine:

The gender debate: science promises an honest investigation of the world

Steven Pinker¹

1. Department of Psychology, Harvard University, Cambridge, Massachusetts 02138, USA

Sir:

Ben Barres's Commentary article "Does gender matter?" (Nature 442, 133–136; 2006) misrepresents my position.

In my book The Blank Slate (Allen Lane, London, 2002), and in a published debate (http://www.edge.org/3rd_culture/debate05/debate05_index.html), I reviewed a large empirical literature showing differences in mean and variance in the distributions of talents, temperaments and life priorities among men and women. Given these differences, some favouring men, some women, it is unlikely that the proportions of men and women in any profession would be identical, even without discrimination. That is probably one of several reasons that the sex ratio tips towards women in some scientific disciplines (such as my own, developmental psycholinguistics) and towards men in others. Barres renders this conclusion as "a whole group of people is innately wired to fail" — an egregious distortion.

Barres claims that I have denied that sex discrimination is a significant factor in professional life, whereas I have repeatedly stated the opposite, and indeed provided a jacket endorsement for Virginia Valian's book Why So Slow? (MIT Press, Cambridge, 1998) that summarized the evidence.

As for encouraging women in science: in my experience, students of both sexes are attracted to science because it promises an honest investigation into how the world works, an alternative to the subjectivity, simplistic dichotomies and moralistic name-calling that characterize politics and personal quarrels. Let's hope Barres's Commentary article does not discourage them.

Readers are encouraged to add their comments to the Ben Barres Commentary on the Nature News Blog at: http://blogs.nature.com/news/blog/2006/07/
does_gender_matter.html.

Personality Predicts Responsivity of the Brain Reward System

The Journal of Neuroscience has started a new feature: short reviews of a recent paper in the Journal, written exclusively by graduate students or postdoctoral fellows. They are meant to mimic the journal clubs that exist in many academic department or institutions.

A recent entry by J. B. Engelmann discusses a paper by Beaver et al. that examines the relationship between a personality trait, reward sensitivity, and activity of the brain reward system measured by functional magnetic resonance imaging. A study like this is relevant to understanding the over-consumption of appetizing high-caloric foods that has contributed to the dramatic increase in obesity within the past 20 years, making obesity a top 10 global health threat. Here are some clips from the review and article:

Figure - A highly simplified schematic diagram outlines the connections between central nodes in the brain reward system (modified from Berridge and Robinson, 2003). Animal as well as human neuroimaging studies have implicated this network in the hedonic and motivational effects of natural rewards and drugs of abuse, such as food and amphetamine. AMYG, Amygdala; NAC, nucleus accumbens; OFC, orbitofrontal cortex; VP, ventral pallidum; VTA/SN, ventral tegmental area/substantia nigra.

Beaver et al. showed that reward sensitivity, as assessed by the Behavioral Inhibition Scale/Behavioral Activation Scale, predicted neural responses to pictures of appetizing foods in the network of the brain regions outlined in the Figure. Functional magnetic resonance imaging, in conjunction with a blocked experimental design, was used to record blood oxygenation-level dependent (BOLD) responses while participants passively viewed pictures of foods from four different categories...The authors found increased activation in orbitofrontal cortex (appetizing vs nonfood objects) and bilateral ventral striatum (appetizing vs bland foods). Interestingly, there was a dissociation between left and right orbitofrontal cortex such that appetizing food stimuli activated the left orbitofrontal cortex, whereas disgusting food stimuli activated the right orbitofrontal cortex.

Beaver et al. provide an important link between human behavioral research that has demonstrated an association between trait reward sensitivity and unhealthy eating habits and animal research implicating the reward network in hyperphagia and increased intake of high-caloric foods. Their findings thus offer a possible explanation for why some individuals overeat compulsively. It will be interesting to establish a more direct link between compulsive overeating and responsivity of the reward system, for instance by correlating activity in the reward system in response to images depicting appetizing foods and body mass index. Finally, an abundance of parallels between obesity and drug addiction points to similarities in the underlying brain mechanisms and neural adaptations that accompany these two conditions

How do we persist when our molecules do not?

John McCrone wrote a brief essay on this topic several years ago in the now-defunct Science and Consciousness Review (or, can anyone point me to a newer URL that works??). I thought that it is worth repeating and abstracting here:

Our entire brain is recycled about every two months, and different components of the synapses that transmit information between nerve cells replace themselves, molecular for molecule, on a time scale of hours to days. All of these synapses and the intricate network of trillions of connections that they form have been crafted by our experience to make us who we are. How can all this remain stable when the large molecules that make synapses seem to be boiling, falling apart nearly as soon as they are made?

Synapses turn out to be reflecting a living confluence of top-down and bottom-up pressures.. (Bottom up: gene or RNA expression patterns remembering what the state of a synapse should be; top down: a constant replaying, or jangling trace, that helps keep labile synapses stabilized). The information is out there in the whole system and it is making the synaptic patterns we observe.

"This kind of topsy-turvey picture can only be resolved by taking a more holistic view of the
brain as the organ of consciousness. The whole shapes the parts as much as the parts shape
the whole. No component of the system is itself stable but the entire production locks together
to have stable existence. This is how you can manage to persist even though much of you is
being recycled by day if not the hour."

Whale Song and Wavelets.... and some piano

An article by G. Cuda in today's NYTimes points out interesting work by Mark Fischer that transforms whale song from what sounds like a series of clicks into a visual art form using wavelet technology. Several beautiful videos of his work can be seen at Google Video. Intricate detail is captured without losing the bigger picture, and presentation in circular form makes repeated patterns more evident. Patterns are unique to different whale species, and even to individuals in a group. Presentation in this form might aid researcher trying to show that repetitions in whale songs follow grammatical rules similar to those of human language.

And, speaking of sounds, I might mention the totally unrelated point that I am starting to put some of my piano recordings and videos from this summer on my website.

Graphic credit, copyright: NYTimes

Living longer and better.....

The July 30 Sunday New York Times has a fascinating article comparing longevity and health in men over the period 1850-2000 (data taken mainly from military records).

"Humans in the industrialized world have undergone a form of evolution that is unique not only to humankind, but unique among the 7,000 or so generations of humans who have ever inhabited the earth. The difference does not involve changes in genes, as far as is known, but changes in the human form. It shows up in several ways, from those that are well known and almost taken for granted, like greater heights and longer lives, to ones that are emerging only from comparisons of health records. The biggest surprise emerging from the new studies is that many chronic ailments like heart disease, lung disease and arthritis are occurring an average of 10 to 25 years later than they used to. There is also less disability among older people today, according to a federal study that directly measures it. And that is not just because medical treatments like cataract surgery keep people functioning. Human bodies are simply not breaking down the way they did before. Even the human mind seems improved. The average I.Q. has been increasing for decades, and at least one study found that a person’s chances of having dementia in old age appeared to have fallen in recent years. The proposed reasons are as unexpected as the changes themselves. Improved medical care is only part of the explanation; studies suggest that the effects seem to have been set in motion by events early in life, even in the womb, that show up in middle and old age."

"In 1900, 13 percent of people who were 65 could expect to see 85. Now, nearly half of 65-year-olds can expect to live that long. People even look different today. American men, for example, are nearly 3 inches taller than they were 100 years ago and about 50 pounds heavier."

"Today’s middle-aged people are the first generation to grow up with childhood vaccines and with antibiotics. Early life for them was much better than it was for their parents, whose early life, in turn, was much better than it was for their parents. And if good health and nutrition early in life are major factors in determining health in middle and old age, that bodes well for middle-aged people today. Investigators predict that they may live longer and with less pain and misery than any previous generation."

There is also the concern, however, that obesity could lead to so much diabetes and heart disease that life expectancy could level off or even decline within the first half of this century.


Graphic: credit and copyright, N.Y. Times

Cracking the Language Code...

An interesting article by McNealy et al. in J. Neuroscience begins to look at the neural basis of detecting word boundaries in continuous speech using functional magnetic resonance imaging (fMRI). From their abstract: "the neural substrate of word segmentation was examined on-line as participants listened to three streams of concatenated syllables, containing either statistical regularities alone, statistical regularities and speech cues, or no cues. Despite the participants’ inability to explicitly detect differences between the speech streams, neural activity differed significantly across conditions, with left-lateralized signal increases in temporal cortices observed only when participants listened to streams containing statistical regularities, particularly the stream containing speech cues. In a second fMRI study, designed to verify that word segmentation had implicitly taken place, participants listened to trisyllabic combinations that occurred with different frequencies in the streams of speech they just heard ("words," 45 times; "partwords," 15 times; "nonwords," once). Reliably greater activity in left inferior and middle frontal gyri was observed when comparing words with partwords and, to a lesser extent, when comparing partwords with nonwords. Activity in these regions, taken to index the implicit detection of word boundaries, was positively correlated with participants’ rapid auditory processing skills. "


Figure: left superior temporal gyrus activity associated with listening to the artificial language conditions (compared with the random syllables condition) during the speech stream exposure task was significantly correlated with participants’ ability to discriminate words that occurred in the artificial languages. Credit: J. Neuroscience

These findings provide a neural signature of on-line word segmentation in the mature brain and an initial model with which to study developmental changes in the neural architecture involved in processing speech cues during language learning.

Face Blindness - hereditary prosopagnosia

One of the most striking consequences of damage to the medial occipitotemporal region of the brain can be the loss of the ability to recognize familiar faces. Patients know only that a face is a face, and can name its parts. There is a website devoted to this disorder. The accquired condition is rare, and inherited or congenital forms of prosopagnosia have been assumed to be even more rare. Kennerknecht et al., however, have now shown that in one group of 689 students, 17 (~2.5%) had congenital prosopagnosia. It turns out that this condition can easily go undiagnosed, because subjects develop alternate strategies for identifying people — they remember their clothes, mannerisms, gait, hairstyle or voice, and by using such techniques, many can compensate quite well. Bakalar, in a review of this work in the July 18 New York Times, notes that people with face blindness can typically understand facially expressed emotions — they know whether a face is happy or sad, angry or puzzled. They can detect subtle facial cues, determine gender and even agree with everyone else about which faces are attractive and which are not. In other words, they see the face clearly, they just do not know whose face they are looking at, and cannot remember it once they stop looking. A specific gene for the disorder has not been found, but evidence is mounting that the trait is inherited. The pedigrees that have been established so far are compatible with autosomal dominant inheritance.”

Nice and Nasty Rats.... Religion and Science

Today's science section of the New York Times has several articles worth noting.

Some remarkable experiments were started in the former Soviet Union in 1959 by Dmitri Belyaev, who decided to study the genetics of domestication and find what qualities were selected for by the neolithic farmers who developed most major farm species about 10,000 years ago. He decided to select for a single criterion: tameness. Starting by breeding silver foxes from the wild, after only eight generations animals that would tolerate human presence became common, and after 40 years and the breeding of 45,000 foxes, a group had emerged that were as tame and as eager to please as a dog. The tame silver foxes had begun to show white patches on their fur floppy ears, rolled tails and smaller skulls, like many other domesticated species. They also exhibited the unusual ability of dogs to understand human gestures (something Chimpanzees can't manage at all). Belyaev also bred a parallel colony of vicious foxes, but realizing that genetics can be better studied in smaller animals, he started working with local wild rats. In only sixty generations separate breeds of very tame and very ferocious rats were obtained. Paabo's laboratory in Germany is now crossing the tame and aggressive strains to find genetic sites that correlate with these behaviors. Such sites could then be examined in tame and aggressive individuals in other mammalian species, including humans... Perhaps an important part of homminid evolution was a human self-domestication that involved ostracizing (blocking the breeding of) individuals who were too aggressive.

The article by Dean in the same NYTimes issue provides a review of recent books on the clash between religion and science, and the debate over whether faith in God can coexist with faith in the scientific method. Professors of either faith or science acknowledge that they cannot prove that God either does or does not exist. Evolutionary psychological explanation of why religious belief seems to be universal among Homo sapiens are still "just-so" stories, very far from being proved.

The book by Lewis Wolpert "Six Impossible Things Before Breakfast: The Evolutionary Origins of Belief" (published in England, due in the U.S. in January) looks quite interesting:

"Dr. Wolpert writes about the way people think about cause and effect, citing among other work experiments on how we reason, how we assess risk, and the rules of thumb and biases that guide us when we make decisions. He is looking into what he calls “causal belief” — the idea that events or conditions we experience have a cause, possibly a supernatural cause.

Human reasoning is “beset with logical problems that include overdependence on authority, overemphasis on coincidence, distortion of the evidence, circular reasoning, use of anecdotes, ignorance of science and failures of logic,” he writes. And whatever these traits may say about acceptance of religion, they have a lot to do with public misunderstanding of science.

So, he concludes, “We have to both respect, if we can, the beliefs of others, and accept the responsibility to try and change them if the evidence for them is weak or scientifically improbable.”

This is where the scientific method comes in. If scientists are prepared to state their hypotheses, describe how they tested them, lay out their data, explain how they analyze their data and the conclusions they draw from their analyses — then it should not matter if they pray to Zeus, Jehovah, the Tooth Fairy, or nobody.

Their work will speak for itself."