Friday, September 28, 2007

Prospection: simulation of future unique to humans

Gilbert and Wilson offer a concise review of our unique human ability to simulate the future, covering brain regions involved and stereotyped errors that occur (PDF here). (I did a series of posts in June, 2006 abstracting Gilberts book "Stumbling on Happiness." You can use the blog search box to find them by entering the word "stumbling.") Here are some clips:


Prefeelings will be reliable predictors of subsequent hedonic experiences when two conditions are met. As the figure shows, when we are in the present (T1) attempting to predict our hedonic reaction to an event in the future (H2), our present hedonic experience (H1) is influenced by our simulation of the future event (e1) as well as by contextual factors (e1), such as the events that are occurring in the present, the thoughts we are having in the present, our present bodily states, and so on. We feel better when we imagine going to the theater than to the dentist, but we feel better imagining either event on a sunny day than on a rainy day, or when we are well rather than ill. Similarly, our future hedonic experience (H2) will be influenced both by our perception of the event (e2) and by contextual factors (e2). Because our hedonic experiences are influenced both by our mental representation of the event and by contextual factors, our present hedonic experience will be a reliable predictor of our future hedonic experience if and only if (i) our simulation of the event at T1 exerts the same influence on our hedonic experience at T1 as our perception of the event at T2 exerts on our hedonic experience at T2, and (ii) contextual factors at T1 exert the same influence on our hedonic experience at T1 as contextual factors at T2 exert on our hedonic experience at T2. In other words, H1 = H2 if and only if e1 = e2 and e1 = e2. Errors in prospection arise from the fact that people use their prefeelings to make hedonic predictions even when one or both of these conditions is not met. These errors are of four kinds.

Simulations are unrepresentative. We naturally imagine our next dental appointment by remembering our last one.... research suggests that people often use unrepresentative memories as a basis for simulation. For example, when people who have missed trains in the past are asked to imagine missing a train in the future, they tend to remember their worst train-missing experience rather than their typical train-missing experience.

Simulations are essentialized. When we imagine "going to the theater next week," we don't imagine every detail of the event, but rather, we imagine the essential features that define it. We imagine seeing a stage filled with actors but we do not imagine parking the car, checking our coat, or finding our seat. The problem with omitting inessential features from simulations is that such features can profoundly influence our subsequent hedonic experience... Because simulations omit inessential features, people tend to predict that good events will be better and bad events will be worse than they actually turn out to be. The young couple who simulate the joys of parenthood but fail to simulate the drudgery of diapers are unlikely to have the hedonic experience they imagined.

Simulations are abbreviated. If we imagined each and every moment of the events we were simulating, our simulations would take as long as the events themselves. Simulations are naturally abbreviated and represent just a few, select moments of a future event. The moments they select tend to be the early ones. When people imagine what their lives would be like if they won the lottery or became paraplegic, they are more likely to imagine the first day than the two-hundred-and-ninety-seventh. The problem with imagining only the early moments of an event is that hedonic reactions to events typically dissipate over time, which means that mental simulations tend to the moments that evoke the most intense pleasure or pain.

Simulations are decontextualized. Research shows that people often do not consider the potentially significant differences between contextual factors at T1 and T2 when using their present hedonic state to predict their future hedonic state. For example, hungry people mistakenly expect to like eating spaghetti for breakfast the next day, and sated people mistakenly expect to dislike eating it for dinner the next day. People who have just exercised mistakenly expect to enjoy drinking water the next day more than do people who are about to exercise (53). In both cases, people do not seem to realize that their present hunger and thirst are influencing their hedonic reactions to simulated future consumption. They ignore the fact that the contextual factors that are presently exerting an influence at T1 (i.e., hunger and thirst) will not exert the same influence at T2.
Their conclusion makes a nice summary of how modern and ancient brain systems interact in imagining possible future feelings:
Mental simulation is the means by which the brain discovers what it already knows. When faced with decisions about future events, the cortex generates simulations, briefly tricking subcortical systems into believing that those events are unfolding in the present and then taking note of the feelings these systems produce. The cortex is interested in feelings because they encode the wisdom that our species has acquired over millennia about the adaptive significance of the events we are perceiving. Alas, actually perceiving a bear is a potentially expensive way to learn about its adaptive significance, and thus evolution has provided us with a method for getting this information in advance of the encounter. When we preview the future and prefeel its consequences, we are soliciting advice from our ancestors.

This method is ingenious but imperfect. The cortex attempts to trick the rest of the brain by impersonating a sensory system. It simulates future events to find out what subcortical structures know, but try as it might, the cortex cannot generate simulations that have all the richness and reality of genuine perceptions. Its simulations are deficient because they are based on a small number of memories, they omit large numbers of features, they do not sustain themselves over time, and they lack context. Compared to sensory perceptions, mental simulations are mere cardboard cut-outs of reality. They are convincing enough to elicit brief hedonic reactions from subcortical systems, but because they differ from perceptions in such fundamental ways, the reactions they elicit may differ as well. Although prospection allows us to navigate time in a way that no other animal can, we still see more than we foresaw.

Evolving size of the social brain.

Dunbar and Shultz ask why primates have such large brains, compared to their body mass, compared with other animals. Here is their abstract, followed by a central clip from their article:

The evolution of unusually large brains in some groups of animals, notably primates, has long been a puzzle. Although early explanations tended to emphasize the brain's role in sensory or technical competence (foraging skills, innovations, and way-finding), the balance of evidence now clearly favors the suggestion that it was the computational demands of living in large, complex societies that selected for large brains. However, recent analyses suggest that it may have been the particular demands of the more intense forms of pairbonding that was the critical factor that triggered this evolutionary development. This may explain why primate sociality seems to be so different from that found in most other birds and mammals: Primate sociality is based on bonded relationships of a kind that are found only in pairbonds in other taxa.

Figure - In anthropoid primates, mean social group size increases with relative neocortex volume (indexed as the ratio of neocortex volume to the volume of the rest of the brain). Solid circles, monkeys; open circles, apes. Regression lines are reduced major axis fits.


The important issue in the present context is the marked contrast between anthropoid primates and all other mammalian and avian taxa (including, incidentally, prosimian primates): Only anthropoid primates exhibit a correlation between social group size and relative brain (or neocortex) size. This quantitative relationship is extremely robust; no matter how we analyze the data (with or without phylogenetic correction, using raw volumes, or residuals or ratios against any number of alternative body or brain baselines) or which brain data set we use (histological or magnetic resonance imaging derived, for whole brain, neocortex, or just the frontal lobes), the same quantitative relationship always emerges. This suggests that, at some early point in their evolutionary history, anthropoid primates used the kinds of cognitive skills used for pairbonded relationships by vertebrates to create relationships between individuals who are not reproductive partners. In other words, in primates, individuals of the same sex as well as members of the opposite sex could form just as intense and focused a relationship as do reproductive mates in nonprimates. Given that the number of possible relationships is limited only by the number of animals in the group, primates naturally exhibit a positive correlation between group size and brain size. This would explain why, as primatologists have argued for decades, the nature of primate sociality seems to be qualitatively different from that found in most other mammals and birds. The reason is that the everyday relationships of anthropoid primates involve a form of "bondedness" that is only found elsewhere in reproductive pairbonds.

Thursday, September 27, 2007

MindBlog's home this morning...


The 1860 stone schoolhouse with its satellite dishes.

Nonhuman primates perceive human goals

Hauser and collaborators do a clever experiment to demonstrate that several primates can make inferences about a human experimenters goal that cannot be explained by simple associative learning. This means that our capacity to infer rational, goal-directed action derives from capabilities present in monkeys ~40 million years ago. Here is their abstract and a figure showing the basic idea of the experiment.

Humans are capable of making inferences about other individuals' intentions and goals by evaluating their actions in relation to the constraints imposed by the environment. This capacity enables humans to go beyond the surface appearance of behavior to draw inferences about an individual's mental states. Presently unclear is whether this capacity is uniquely human or is shared with other animals. We show that cotton-top tamarins, rhesus macaques, and chimpanzees all make spontaneous inferences about a human experimenter's goal by attending to the environmental constraints that guide rational action. These findings rule out simple associative accounts of action perception and show that our capacity to infer rational, goal-directed action likely arose at least as far back as the New World monkeys, some 40 million years ago.


Figure: During each trial, an experimenter presented subjects with two potential food containers, performed an action on one, and then allowed the subject to select one of the containers. In the intentional condition, the experimenter reached directly for and grasped the container. In the accidental condition, the experimenter flopped his hand onto the container with palm facing upwards in a manner that appeared, from a human perspective, accidental and non–goal-directed (13). If non-human primates fail to distinguish between intentional and accidental actions when making inferences about others' goals, attending to the mere association of the hand and container, then they should show the same pattern of searching in both conditions—that is, approach the experimenter-contacted container. However, if they distinguish between intentional and accidental actions, then they should selectively inspect the container targeted by the experimenter'sintentional action but not that targeted by accidental action.


A "language gene" in echolocating bats

Slightly altered abstract from Li et al.:

FOXP2 is a transcription factor implicated in the development and neural control of orofacial coordination, particularly with respect to vocalisation. [Thus, it is not really a "language gene" as indicated in many popular press reports.] Observations that orthologues show almost no variation across vertebrates yet differ by two amino acids between humans and chimpanzees have led to speculation that recent evolutionary changes might relate to the emergence of language. Echolocating bats face especially challenging sensorimotor demands, using vocal signals for orientation and often for prey capture. To determine whether mutations in the FoxP2 gene could be associated with echolocation, we sequenced FoxP2 from echolocating and non-echolocating bats as well as a range of other mammal species. We found that contrary to previous reports, FoxP2 is not highly conserved across all nonhuman mammals but is extremely diverse in echolocating bats. We detected divergent selection (a change in selective pressure) at FoxP2 between bats with contrasting sonar systems, suggesting the intriguing possibility of a role for FoxP2 in the evolution and development of echolocation. We speculate that observed accelerated evolution of FoxP2 in bats supports a previously proposed function in sensorimotor coordination.

Wednesday, September 26, 2007

Naturopathy wins over physical therapy advice?

Chronic lower back pain is perhaps the most commonly reported workplace disability. Szczurko et al. conducted a randomized clinical trial of 75 postal service employees experiencing more than six weeks of chronic back pain, dividing them to receive Naturopathic care (n = 39) or standardized physiotherapy (n = 36) over a period of 12 weeks. The study was conducted in clinics on-site in postal outlets. Participants in the Naturopathic care group received dietary counseling, deep breathing relaxation techniques and acupuncture. The control intervention received education and instruction on physiotherapy exercises using an approved education booklet. The authors suggest that naturopathic care provided statistically significant greater improvement than physiotherapy advice.

The naturopathic route involved hands-on intervention (acupuncture), and there is this curious point suggesting some rather significant motivational differences:

Data was available on 100% (39) of the naturopathic care group at week 8 and 75% (27) of the control group at week 8. Complete data on participants at week 12 was available on 92% and 63% respectfully.

Social cognitive skills unique to humans...

From Tomasello's group in Leipzig comes an article (PDF here), arguing for a distinctively human social cognitive intelligence rather a more "general intelligence" as distinguishing humans from the great apes. Here is their abstract:

Humans have many cognitive skills not possessed by their nearest primate relatives. The cultural intelligence hypothesis argues that this is mainly due to a species-specific set of social-cognitive skills, emerging early in ontogeny, for participating and exchanging knowledge in cultural groups. We tested this hypothesis by giving a comprehensive battery of cognitive tests to large numbers of two of humans' closest primate relatives, chimpanzees and orangutans, as well as to 2.5-year-old human children before literacy and schooling. Supporting the cultural intelligence hypothesis and contradicting the hypothesis that humans simply have more "general intelligence," we found that the children and chimpanzees had very similar cognitive skills for dealing with the physical world but that the children had more sophisticated cognitive skills than either of the ape species for dealing with the social world.

Tuesday, September 25, 2007

The decline of memory

J.L. Bader notes that Britney Spear's memory lapse while she was lip-synching during the recent MTV music video awards is a reflection of the general decline of dependence on memory in our culture. Why remember anything, when you can always google or wikipedia it; and all your contacts and phone numbers are stored in your cell phone? (And yes, I was one of the $200 beta testers of the Apple iPhone.) Some clips:

Oration and recitation, once staples of the American school system, have largely been phased out. Rhetoric programs at universities have narrowed, merged with communications departments, or been eliminated altogether...“We don’t have that kind of oral culture anymore,” said Prof. James Engell, author of “The Committed Word: Literature and Public Values,” who teaches a rhetoric course at Harvard. “We are in a culture that devalues our sense of memory.” Back when John Quincy Adams was teaching it, Mr. Engell said, “rhetoric was an umbrella where you got moral philosophy, the development of literary taste, intellectual prose, aesthetic appreciation, memorization and oral presentation. The ultimate object of this was what the Greeks called phronesis, or practical wisdom.”

...But contemporary scientists have discovered that memorization exercises can stave off dementia, introducing a new world of “neurobics.” Memory needs a workout as much as the abs do. Researchers have even shown that reciting poetry in dactylic hexameter can help synchronize heartbeats with breathing.

Lucid Dreaming makes the Styles section...

My, my, my..... how rapidly esoteric mind things become trendy. The lead article of the Sunday Styles section of the Sept 16 NY Times featured lucid dreaming. I've been to several consciousness meeting in which whole sessions were devoted to this capability. Actually it is not that esoteric...you probably have had experiences of being aware you were dreaming, of watching the action as a observer. The capability can be trained, and one can sometimes direct the action (even to the extent of indulging in some sexual fantasies that may not exactly be playing out in real life). I have played with this capability in my own dreaming, and find it to be much easier and cheaper than getting into computer facilitated alternative realities such as Second Life (I tried that too, felt like a dunce, and can't imagine how anyone finds the time.....).

Monday, September 24, 2007

Did Alex really "want" a cracker?

New York Times science writer George Johnson, who is one very intelligent guy, has done a nice piece on the capabilities and history of Alex the parrot (PDF here). I was unaware of several of the behaviors that had been noted in Alex:

“Want a nut!” Alex demanded. The interview was over. “Want a nut!” he repeated. “Nnn ... uh ... tuh.”...Dr. Pepperberg was flabbergasted. “Not only could you imagine him thinking, ‘Hey, stupid, do I have to spell it for you?’ ” she said. “This was in a sense his way of saying to us, ‘I know where you’re headed! Let’s get on with it.’ ”....She is quick to concede the impossibility of proving that the bird was actually verbalizing its internal deliberations. Only Alex knew for sure.

Next to infinity, one of the hardest concepts to grasp is zero. Toward the end of his life Alex may have been coming close. In a carnival shell game, an experimenter would put a nut under one of three cups and then shuffle them around. Alex would pick up the cup where the prize was supposed to be. If it wasn’t there he’d go a little berserk — a small step, maybe, toward understanding nothingness.

A bigger leap came in an experiment about numbers, in which the parrot was shown groups of two, three and six objects. The objects within each set were colored identically, and Alex was asked, “What color three?”.... “Five,” he replied perversely (he was having a bad attitude day), repeating the answer until the experimenter finally asked, “O.K., Alex, tell me, ‘What color five?’ ”....“None,” the parrot said....Bingo. There was no group of five on the tray. It was another of those high huneker moments. Alex had learned the word “none” years before in a different context. Now he seemed to be using it more abstractly....Dr. Pepperberg reported the result with appropriate understatement: “That zero was represented in some way by a parrot, with a walnut-sized brain whose ancestral evolutionary history with humans likely dates from the dinosaurs, is striking.”

This week's music - Debussy, Minuette from Suite Bergmanesque

Recorded Sept. 13 on my Steinway B at Twin Valley.

Let the kids decide.....

Friday, September 21, 2007

Placebo effect on human opiod pain system

A recent issue of Nature Reviews Neuroscience points to an interesting article by Wagner et al.
(open access).

The mere expectancy of pain relief has been shown to reduce pain in a manner that is reversible by opioid antagonists. Using positron-emission tomography and a mu-opioid-receptor selective radiotracer, Wagner et al. were able to measure the placebo-induced activation of the opioid system in specific brain regions. They found an increase in opioid neurotransmission in regions that have a central role in pain processing, demonstrating that placebo analgesic treatments potentiate the endogenous opioid response to painful stimuli.

Figure - Connectivity analysis of opioid binding potential. (A) 3D rendering of connectivity among regions that show placebo opioid responses.

The five "most popular" consciousness papers for August 2007

I pass on the report from the ASSC (Assoc. for Sci. Study of Cons.) of the papers most downloaded from their eprint archives in August:

1. Mashour, George A. (2007) Inverse Zombies, Anesthesia Awareness, and the
Hard Problem of Unconsciousness. In: 11th Annual Meeting of the ASSC, Las
Vegas.
(936 downloads from 21 countries). http://eprints.assc.caltech.edu/294/
2. Windt, Jennifer Michelle and Metzinger, Thomas (2006) The philosophy of
dreaming and self-consciousness: What happens to the experiential subject
during the dream state? In: The new science of dreaming (928 downloads from
19 countries). http://eprints.assc.caltech.edu/200/
3. Koriat, A. (2006) Metacognition and Consciousness. In: Cambridge handbook
of consciousness. CUP (801 downloads from 18 countries)
http://eprints.assc.caltech.edu/175/
4. Rosenthal, David (2007) Consciousness and its function. In: 11th annual
meeting of the Association for the Scientific Study of Consciousness, 22-25
June 2007, Las Vegas, USA. (741 downloads from 19 countries).
http://eprints.assc.caltech.edu/293/
5. Rosen, Alan and Rosen, David B. (2006) The Design of a
Sensation-generating Mechanism in the Brain: A first step towards a
quantitative definition of consciousness. Consciousness and Cognition,
CONCOG-06-00174 (596 downloads from 18 countries).
http://eprints.assc.caltech.edu/195/

Thursday, September 20, 2007

Mind Over Manual

This is the title of an Op-Ed piece in the 9/13/2007 NY Times by Sally Satel which describes the difficulties and issues faced by the forthcoming revision (due in 2012) of the Diagnostic and Statistical Manual of Mental Disorders (PDF here). It faces issue such as the 40-fold jump in diagnosis of childhood bipolar disorder from 1994 to 2003. Some clips from the article:

We still don’t know how much of this increase represents long-overdue care of mentally ill youth and how much comes from facile labeling of youngsters who are merely irritable and moody...Part of the confusion stems from the lack of a discrete definition of juvenile bipolar illness in the diagnostic manual. But there is a deeper problem: despite the great progress being made in neuroscience, we still don’t have a clear picture of the brain mechanisms underlying bipolar illness — or most other mental illnesses... many patients meet several diagnostic definitions at once. Roughly half of adults with clinical depression, for example, also have symptoms that fit the definition of an anxiety disorder...the link between diagnosis and treatment is relatively weak. Antidepressants like Prozac help treat not only depression but also panic disorder, obsessive-compulsive disorder, bulimia and social phobia. This explains why clinicians often treat by symptom rather than diagnosis. Paranoia, for example, is treated with an antipsychotic drug whether it occurs in the context of schizophrenia, bipolar illness or methamphetamine use.

An updated manual..is unlikely to transform treatment substantially — after all, revising diagnoses is still just another way to describe mental conditions we don’t fully understand. But these refinements may well stimulate valuable new inquiry, enabling swifter progress in understanding the mechanisms of disease, better deployment of treatments we have and more efficient discovery of new ones.

Walking the Walk

A new study of human locomotion shows a pattern of changes in independent neural controllers for left and right legs. Here is the abstract from Choi and Bastian and a summary figure from the review by Miall.

Human walking is remarkably adaptable on short and long timescales. We can immediately transition between directions and gait patterns, and we can adaptively learn accurate calibrations for different walking contexts. Here we studied the degree to which different motor patterns can adapt independently. We used a split-belt treadmill to adapt the right and left legs to different speeds and in different directions (forward versus backward). To our surprise, adults could easily walk with their legs moving in opposite directions. Analysis of aftereffects showed that walking adaptations are stored independently for each leg and do not transfer across directions. Thus, there are separate functional networks controlling forward and backward walking in humans, and the circuits controlling the right and left legs can be trained individually. Such training could provide a new therapeutic approach for correcting various walking asymmetries.

Four neural systems are postulated, controlling forward (FW) and backward (BW) walking in left and right legs.
(a) In forward split-belt training, indicated by the dashed box, the right belt is faster than the left, inducing relative changes in the left and right forward-walking circuits (dotted circles). When walking on the tied-belt was tested after adaptation, an aftereffect was seen in forward walking, but not in backward walking. (b,c) In hybrid adaptive walking (b, diagonal dashed box), the left leg is on the slow backward belt and the right leg on the fast forward belt. This induced changes that were evident as aftereffects in both forward and backward walking, and that were compatible with this model of four functionally separate controllers, but were incompatible with a model (c, arrows) in which functional connections between these controllers are modified by learning.

Wednesday, September 19, 2007

Roles of parietal and prefrontal cortex in working memory

Champod and Petrides distinguish monitoring and manipulation tasks carried out by working memory and demonstrate different brain correlates. Their abstract, and a figure:

Numerous functional neuroimaging studies reported increased activity in the middorsolateral prefrontal cortex (MDLFC) and the posterior parietal cortex (PPC) during the performance of working memory tasks. However, the role of the PPC in working memory is not understood and, although there is strong evidence that the MDLFC is involved in the monitoring of information in working memory, it is also often stated that it is involved in the manipulation of such information. This event-related functional magnetic resonance imaging study compared brain activity during the performance of working memory trials in which either monitoring or manipulation of information was required. The results show that the PPC is centrally involved in manipulation processes, whereas activation of the MDLFC is related to the monitoring of the information that is being manipulated. This study provides dissociation of activation in these two regions and, thus, succeeds in further specifying their relative contribution to working memory.

Figure: Activity in the manipulation minus monitoring and in the monitoring minus manipulation comparisons. Cortical surface renderings in standard stereotaxic space of a subject's brain are shown on the left. (a) Increased activity in the left IPS obtained from the manipulation minus monitoring comparison. The vertical blue line on the left hemisphere cortical surface rendering indicates the anteroposterior level of the coronal section illustrated on the right. (b) Increased activity in the right MDLFC obtained from the monitoring minus manipulation comparison. The vertical green line on the right hemisphere cortical surface rendering indicates the anteroposterior level of the coronal section illustrated on the right side. CS, central sulcus; PoCS, postcentral sulcus; PCS, precentral sulcus; SFS, superior frontal sulcus; IFS, inferior frontal sulcus; MFS, middle frontal sulcus.

The obsession with inhibiting aging...

Coming upon the website of the Methuselah Foundation and the Methuselah Mouse prize begins to bring out the curmudgeon in me. I'm fine with prolonging vitality thought better understanding of the chemistry of aging (check out BrainReady.com, and previous lists of anti-aging sites I've put on the blog, check blog category "aging"), but fantasies about immortality strike me a pure hubris. Contra Dylan Thomas, I think we bloody ought to go gently into that good night, once we've done a good turn here....

Tuesday, September 18, 2007

Daytime sleep consolidates motor memory

Here is the abstract from Korman et al. :

Two behavioral phenomena characterize human motor memory consolidation: diminishing susceptibility to interference by a subsequent experience and the emergence of delayed, offline gains in performance. A recent model proposes that the sleep-independent reduction in interference is followed by the sleep-dependent expression of offline gains. Here, using the finger-opposition sequence–learning task, we show that an interference experienced at 2 h, but not 8 h, following the initial training prevented the expression of delayed gains at 24 h post-training. However, a 90-min nap, immediately post-training, markedly reduced the susceptibility to interference, with robust delayed gains expressed overnight, despite interference at 2 h post-training. With no interference, a nap resulted in much earlier expression of delayed gains, within 8 h post-training. These results suggest that the evolution of robustness to interference and the evolution of delayed gains can coincide immediately post-training and that both effects reflect sleep-sensitive processes.
And here is a graphic summarizing the results from the review by Diekelmann and Born:
Two ways of consolidating memory of finger tapping skill.
(a) Evolution of finger-to-thumb tapping skill under three experimental key conditions. From top to bottom: after training a specific sequence (Sequence A) in the morning and a first retest 8 h later, a distinct gain in performance developed at the second retest following overnight sleep (purple). Interference by training on a different sequence (Sequence B) 2 h after training of Sequence A completely abolished any sleep-dependent overnight gain developing between the first and second retest (blue). This overnight gain was restored when subjects napped for 90 min between training of Sequence A and interference training on Sequence B (green). (b) Model of skill memory consolidation. Representations of finger tapping skill are encoded in a temporary store. Stabilization (resistance to interference) of the representation can be achieved either through time-dependent synaptic consolidation (dark green) in the temporary buffer or through sleep-dependent system consolidation (red) that leads to a redistribution of the representation to different neuronal networks for long-term storage. Memory enhancement (delayed gains in performance) requires sleep-dependent system consolidation.

Fly brains/Human brains - similarities in sleep induction

Some membrane signaling pathways important in initiating sleep appeared in a common ancestor of humans and insects! Here is the abstract from Foltenyi et al. (the pathways are complicated, but you can get the over all idea):

Epidermal growth factor receptor (EGFR) signaling in the mammalian hypothalamus is important in the circadian regulation of activity. We have examined the role of this pathway in the regulation of sleep in Drosophila melanogaster. Our results demonstrate that rhomboid (Rho)- and Star-mediated [ed. note - these are proteases] activation of EGFR and ERK signaling increases sleep in a dose-dependent manner, and that blockade of rhomboid (rho) expression in the nervous system decreases sleep. The requirement of rho for sleep localized to the pars intercerebralis, a part of the fly brain that is developmentally and functionally analogous to the hypothalamus in vertebrates. These results suggest that sleep and its regulation by EGFR signaling may be ancestral to insects and mammals.
And a graphic from the review by Colwell:
Proposed role of extracellular signal–regulated kinase (ERK) in the regulation of sleep in Drosophila.
(a) Rho-mediated activation of ERK signaling increases sleep duration. During the night, Rho activation in the pars intercerebralis (PI) leads to the production and secretion of an EGFR ligand. The resulting phosphorylation of EGFR activates ERK in the tritocerebrum (TriC). Although the final targets of this signaling pathway are not known, the phosphorylated ERK seems to stay in the processes of the TriC neurons and may well regulate electrical activity and synaptic transmission in these neurons. (b) During wakefulness, Rho signaling in the PI is proposed to be downregulated, resulting in basal levels of ERK signaling. Inhibition of Rho expression in PI neurons results in decreased sleep levels, with short, fragmented sleep bouts. This observation suggests that these mutant flies have an increased need for sleep but are unable to stay asleep (making them a fly model of insomnia).

Monday, September 17, 2007

This week's music - Rachmaninoff Trio Elegiaque no. 1

Sonny Enslen (cello), Daphne Tsao (violin) and I are doing a final rehearsal of this Rachmaninoff Elegy before performing it for a local music group.

Do you have absolute pitch?

Curious that I came across this article, just after a post on Pavoratti's High C. From Athos et al.

Absolute pitch (AP) is the rare ability to identify the pitch of a tone without the aid of a reference tone. Understanding both the nature and genesis of AP can provide insights into neuroplasticity in the auditory system. We explored factors that may influence the accuracy of pitch perception in AP subjects both during the development of the trait and in later age. We used a Web-based survey and a pitch-labeling test to collect perceptual data from 2,213 individuals, 981 (44%) of whom proved to have extraordinary pitch-naming ability. The bimodal distribution in pitch-naming ability signifies AP as a distinct perceptual trait, with possible implications for its genetic basis. The wealth of these data has allowed us to uncover unsuspected note-naming irregularities suggestive of a "perceptual magnet" centered at the note "A." In addition, we document a gradual decline in pitch-naming accuracy with age, characterized by a perceptual shift in the "sharp" direction. These findings speak both to the process of acquisition of AP and to its stability.
From a commentary by Drayna in the same issue of PNAS:
Absolute pitch is an especially tantalizing trait for genetic analysis. It has an onset early in life, it occurs equally in males and females, it is highly heritable, it is rare in the population, and it appears to be nonsyndromic, that is, unassociated with other conditions. All of these features bode well for the prospects of gene finding. However, unlike most inherited neurological conditions for which affected individuals present themselves to a medical specialist, AP individuals and families have not been easily ascertained. The demonstration by Athos et al. that a web site can be an effective tool for identifying, testing, and recruiting AP subjects is an important development. The identification of the genetic variation that leads to AP is likely to tell us much about a part of the auditory system that is currently obscure, and the results of Athos et al. are indeed encouraging in this quest.

Friday, September 14, 2007

Pavarotti's high C

I'm an opera buff, and can be reduced to a puddle by beautiful singing. Thus I pass on some clips from an essay by Daniel Wakin (PDF here) on the passing of Luciano Pavarotti, regarded as the king of the High C's:

His voice, especially earlier in his career, was remarkable across its range. But that little note, an octave above middle C on the piano, played a role in projecting Mr. Pavarotti’s fame around the world. That is no surprise. The tenor high C has a long and noble tradition, and a healthy dose of mystique...Tenor high C’s are scattered throughout the opera literature. Sometimes tenors transpose the aria down slightly or drop an octave, other times they fake it and edge into falsetto voice, where it is easier to sing. Just as often, they hit it, and hold it, and that moment is one of the most exciting in an opera house. It is moments like those when opera, in addition to the aesthetic joys and emotional satisfactions, can seem like a spectator sport or a circus high-wire act. They’re times when opera audiences cheer or jeer.

But the high C has a more visceral, spine-tingling lure...“The reason it’s so exciting to people is, it’s based on the human cry,” said Maitland Peters, chairman of the voice department at the Manhattan School of Music. “It’s instinctual. It’s like a baby. You’re pulled into it.” When a tenor sings a ringing high C, it seems, “there’s nothing in his way,” Mr. Peters said...The pitch, in itself, has a satisfying quality. The key of C major, after all, is a stable, cheerful, happy key, the one with no sharps or flats.

Sigmund Freud revising his views on religion...

Mark Edmundson offers an essay in the NY Times of 9/9/2007 (PDF here)on the legacy of Freud's last days that I found fascinating. Without renouncing his atheism, Freud describes in a controversial book on Moses what he sees as some useful consequences of the Jewish faith. Here are some clips from the essay:

About two-thirds of the way into the volume, he makes a point that is simple and rather profound — the sort of point that Freud at his best excels in making. Judaism’s distinction as a faith, he says, comes from its commitment to belief in an invisible God, and from this commitment, many consequential things follow. Freud argues that taking God into the mind enriches the individual immeasurably. The ability to believe in an internal, invisible God vastly improves people’s capacity for abstraction. “The prohibition against making an image of God — the compulsion to worship a God whom one cannot see,” he says, meant that in Judaism “a sensory perception was given second place to what may be called an abstract idea — a triumph of intellectuality over sensuality.”

Freud speculates that one of the strongest human desires is to encounter God — or the gods — directly. We want to see our deities and to know them. Part of the appeal of Greek religion lay in the fact that it offered adherents direct, and often gorgeous, renderings of the immortals — and also, perhaps, the possibility of meeting them on earth. With its panoply of saints, Christianity restored visual intensity to religion; it took a step back from Judaism in the direction of the pagan faiths. And that, Freud says, is one of the reasons it prospered.

If people can worship what is not there, they can also reflect on what is not there, or on what is presented to them in symbolic and not immediate terms. So the mental labor of monotheism prepared the Jews — as it would eventually prepare others in the West — to achieve distinction in law, in mathematics, in science and in literary art. It gave them an advantage in all activities that involved making an abstract model of experience, in words or numbers or lines, and working with the abstraction to achieve control over nature or to bring humane order to life. Freud calls this internalizing process an “advance in intellectuality,” and he credits it directly to religion.

Freud’s argument suggests that belief in an unseen God may prepare the ground not only for science and literature and law but also for intense introspection. Someone who can contemplate an invisible God, Freud implies, is in a strong position to take seriously the invisible, but perhaps determining, dynamics of inner life. He is in a better position to know himself. To live well, the modern individual must learn to understand himself in all his singularity. He must be able to pause and consider his own character, his desires, his inhibitions and values, his inner contradictions. And Judaism, with its commitment to one unseen God, opens the way for doing so. It gives us the gift of inwardness.
It seems to me that the same points could be made about Buddhism and other eastern religions.

Thursday, September 13, 2007

Mind-Set matters: More on contruals and the placebo effect altering physiology and perfomance

I am grateful to a blog reader for pointing out an article that adds to one of the threads in this blog, how brief interventions with a small amount of information can alter performance in striking ways. Two previous posts have mentioned how such information can alter math related gender differences and racial achievement gaps. Here is more on how, by altering the stories we tell ourselves, we can fundamentally change our physiology and our performace: Crum and Langer report in Psychological Science (PDF here) that the relationship between exercise and health can be altered by offering a bit of information that changes how exercise is regarded. Here is their abstract:

In a study testing whether the relationship between exercise and health is moderated by one's mind-set, 84 female room attendants working in seven different hotels were measured on physiological health variables affected by exercise. Those in the informed condition were told that the work they do (cleaning hotel rooms) is good exercise and satisfies the Surgeon General's recommendations for an active lifestyle. Examples of how their work was exercise were provided. Subjects in the control group were not given this information. Although actual behavior did not change, 4 weeks after the intervention, the informed group perceived themselves to be getting significantly more exercise than before. As a result, compared with the control group, they showed a decrease in weight, blood pressure, body fat, waist-to-hip ratio, and body mass index. These results support the hypothesis that exercise affects health in part or in whole via the placebo effect.

A study like this makes you wonder how much of the benefit of physical education regimes like yoga, pilates, etc.- versus just being active - are due to such a placebo effect.

Want to avoid snakes?..Heat your tail.

Prey species have evolved a number of tricks to avoid or deceive predators, involving movement, visual, sound, or smell cues. Now infrared cues get added to the list. Rundus et al. have found that California ground squirrels have evolved a clever trick to deceive snakes, who use infrared (heat) detectors in sizing up their potential prey. The squirrel heats its tail as it shakes it, thus giving off the amount of heat expected from a larger animal and making the snake think that it is larger than it really is. Because larger squirrels are more likely to directly attack snakes, the snake thus is more cautious and less likely to strike.

Wednesday, September 12, 2007

Neurocognitive correlates of liberalism and conservatism

David Amodio (who got his Ph.D. here at Wisconsin in 2003) is now at NYU, and with a group of collaborators reports on neuronal correlates of political stance (PDF here). Here is their abstract, followed by a bit of text and a figure:

Political scientists and psychologists have noted that, on average, conservatives show more structured and persistent cognitive styles, whereas liberals are more responsive to informational complexity, ambiguity and novelty. We tested the hypothesis that these profiles relate to differences in general neurocognitive functioning using event-related potentials, and found that greater liberalism was associated with stronger conflict-related anterior cingulate activity, suggesting greater neurocognitive sensitivity to cues for altering a habitual response pattern.

In our study, conflict-related ACC activity was indexed by two ERP components. ERPs are scalp-recorded voltage changes reflecting the concerted firing of neurons in response to a psychological event. The response-locked error-related negativity (ERN), which peaks at approximately 50 ms following an incorrect behavioral response, reflects conflict between a habitual tendency (for example, the Go response) and an alternative response (for example, to inhibit behavior in response to a No-Go stimulus. We also examined the No-Go N2 component, which is believed to reflect conflict-monitoring activity associated with the successful inhibition of the prepotent Go response on No-Go trials7. Relationships between political orientation and these neurocognitive indices were examined using correlation analyses (two-tailed).



Figure 1. The relation between political orientation and a neurocognitive index of conflict monitoring.
(a) Political liberalism was associated with larger No-Go error-related negativity (ERN) amplitudes, as indicated by more negative scores, suggesting greater neurocognitive sensitivity to response conflict. (b) ERP waveforms corresponding to No-Go errors, with the waveform for correct Go responses subtracted, are shown for both liberal and conservative participants (response made at 0 ms; ERN peaked at 44 ms postresponse), with the inset showing the voltage map of the scalp distribution of the ERN. (c) Source localization indicates a dorsal anterior cingulate generator for the ERN, computed at peak amplitude (red line in panel b).

In memoriam - Alex the Parrot

Sad news, reported in the Sept. 11 NY Times. Alex the talking parrot passed away of natural causes last week at the age of 31. I have heard Irene Pepperberg (former wife of a vision colleague of mine) give talks about Alex over a 25 year period. Irene taught Alex to learn scores of words, which he could put into categories, and to count small numbers of items, as well as recognize colors and shapes. His cognitive and language skills appeared to be about as competent as those in trained primates, and like them, he showed no evidence of having the recursive logic capabilities required for grammar and working with digital numbers.

Here is a brief video of Alex performing in his prime:

Tuesday, September 11, 2007

The Blakeslees on the body's own mind...

"The Body Has a Mind of Its Own" is the title of a book being released today, September 11, by Sandra Blakeslee (N.Y.Times Science writer) and her son Matthew Blakeslee (also a science writer, making him the fourth generation of science writers in the family line!). Its subject is the maps that our brain makes of our internal and external worlds, including our feelings, emotions, and sense of self... and how plastic they can be. Much of the work they describe has been the subject of posts on this MindBlog. I enjoyed reading the book, and would highly recommend it. It crams an amazing amount of material into a small space. It is easy to read and engaging.

Here is one of the figures from the book, illustrating how our brain cells adapt to tool use, incorporating the tool into our body image.

How our brain changes when we (or monkeys, as in the figure) use a hand tool to extend our reach. Legend. a) Before learning to use a rake (left) or while passively holding the rake (right) without the intention of using it as a tool, the monkey's hand-centered visual-tacile receptive fields stay confined to the hand's immediate vicinity. But while the monkey is actively wielding the rake (center), the cells' visual receptive fields expand along its length. (Visual or tactile input to the shaded area causes a hand-centered cell in the parietal lobe to fire.) b). The visual-tacile receptive field expansion of one of the monkey's shoulder-centered neurons.

These positive points having been made, I felt during my reading like I was looking over the authors' shoulders as they were writing, and I kept wanting to suggest that the presentation be tightened up with more bottom lines brought up front. Many times I had the "Ah Ha!, why didn't they tell me THIS is where they were going" experience. With one study after another thrown onto the page I found myself loosing the thread. When I did find an interesting nugget I had not be aware of, I was frustrated by the fact that there is no bibliography or list of references provided. It would be very useful for the authors to provide such references on a website associated with the book.

There are many excellent summaries and quotable passages in the book. I like the ending paragraphs, which follow a discussion of the neural correlates of our sense of self, and how distortions in our sense of ownership can occur. A few clips:

So, is the self ultimately "just" an illusion?...According to the neuroscience of body maps - and incidentally, the majority of Eastern religions - in many respects, yes...A key point is that your mind feels like a seamless whole when "all your faculties" are working. But if your body mandala were to go on the fritz in one of a hundred ways, whether through damage to one map or several, or through a severing of between-map connections, you might suddenly experience extra arms, a phantom leg...hemineglect (where half the universe winks out of your awareness), alien hand syndrome, and all manner of delusions and misperceptions. Case studies of brain damage like these are one of the biggest philosophical, not to mention logical, arguments against the idea of a uniatry psychic core. When certain parts of the brain break, certain parts of the mind break; the illusion is spoiled, and the underlying multifariousness of the psyche is exposed......The illusion of the self is that self is a kernel, rather than a distributed, emergent system....Localizations of psychic functions are better said to exist in loops of information processing, or circuits, rather than specific points...the...psychic self...is an orchestra without a conductor or a fixed score, but whose players are so good at collaborative improv that wonderful music keeps flowing out of it. Just as the orchestra has no score and no conductor, the mind has no kernel, no "little man" sitting at the center of the fray directing the action. But it is teeming with noncentral "little men," the brain's motley team of homunculi, who form the backbone of the whole production. And you, thankfully, have the irreducible illusion of being the conductor of yours life's music in all its complexity, emotional nuace, crescendo and diminuendo - the ballad that is the you-ness of you."

This week's music: Beethoven violin/piano sonata no. 3

Daphne Tsao (violin) and I are doing a final rehearsal before playing this piece for two amateur musical performance groups in Madison, Wisconsin: Carnaval and Allegro. This is Beethoven sonata no. 3 for violin and piano, the first movement.

Monday, September 10, 2007

The smell of an alpha male....

Pheromones influence sexual behavior and reproduction in rodents. Mak et al report that:

...the pheromones of dominant (but not subordinate) males stimulate neuronal production in both the olfactory bulb and hippocampus of female mice, which are independently mediated by prolactin and luteinizing hormone, respectively. Neurogenesis induced by dominant-male pheromones correlates with a female preference for dominant males over subordinate males, whereas blocking neurogenesis with the mitotic inhibitor cytosine arabinoside eliminated this preference. These results suggest that male pheromones are involved in regulating neurogenesis in both the olfactory bulb and hippocampus, which may be important for female reproductive success.
I keep wondering if we won't be finding evidence for a version of this effect (perhaps more subtle) in humans... would the cheerleader, like the female rat in the box below, be more likely to hang out with the star quarterback if she had smelled his sweaty jersey a day earlier??

An illustration from the summary review by DiRocco and Xia:
Figure legend: Dominant male pheromones stimulate neurogenesis in females.
(a) Female mice exposed to dominant male pheromones spent more time sniffing the dominant male, whereas females exposed to subordinate male pheromones did not show any preference. (b) Exposing female mice to pheromones from dominant males led to increased neurogenesis in the subventricular zone (SVZ) and dentate gyrus (DG). Pheromones signal the main olfactory epithelium (MOE)–main olfactory bulb (MOB) axis, which relays the signal to the hypothalamus (HYP)–pituitary (PIT) axis, leading to the release of luteinizing hormone (LH) and prolactin (PRL). LH appeared to stimulate neurogenesis in the dentate gyrus of the hippocampus, whereas prolactin induced neurogenesis in the SVZ and MOB. It is hypothesized that pheromone-induced neurogenesis may underlie female mating preference for the dominant male. NC, nasal cavity; RMS, rostral migratory stream; green circles, newborn neurons.

Mistakes were made...Cognitive Dissonance Theory

William Swann reviews the book by Tavris and Aronson "Mistakes Were Made (But Not By Me): Why We Justify Foolish Beliefs, Bad Decisions, and Hurtful Acts." On cognitive dissonance theory:

..the authors' version is that people's brains are wired to find consistency between what they do and their positive images of themselves. Presumably this is why people engage in a wide array of mental gymnastics to salvage their self-esteem rather than own up to their mistakes. The typical outcome is that people twist the truth to make it seem kinder or more flattering than it actually is. In extreme cases, they may engage in distortion and denial of objective reality...dissonance theory can explain many laboratory findings and elements of many naturally occurring phenomena. For example, the authors maintain that when ordinary people blithely agreed to administer dangerously strong electric shocks to hapless learners in Stanley Milgram's classic experiments, the subjects' penchant for self-justification ("the experimenter told me to continue") was a key contributor to their complicity. Similarly, in instances in which prosecutors have refused to back down when DNA evidence has revealed that a defendant was wrongfully sentenced for a crime, Tavris and Aronson attribute theprosecutors' refusal to admit error to pernicious self-justification processes. The authors also maintain that most champions of the repressed-memory movement, when confronted with information suggesting that the "memories" of alleged victims are false, simply dismiss the evidence as being a form of backlash against child victims and incest survivors...As the book's title suggests, one of the topics touched on is contemporary politics. Tavris and Aronson mention in the endnotes that many U.S. presidents have used the phrase "mistakes were made," including Bill Clinton, Ronald Reagan and Richard Nixon. Although Alberto Gonzales's use of the phrase a few months ago ("I acknowledge that mistakes were made here") occurred too recently to make it into the book, the authors do discuss some of the self-justifications and self-deceptions of the current administration. For example, they characterize George W. Bush as "the poster boy for 'tenacious clinging to a discredited belief.'"

Friday, September 07, 2007

The evil that men do - The Lucifer Effect

Robert Levine reviews the recent book "The Lucifer Effect: Understanding How Good People Turn Evil," by Philip Zimbardo, the man who did the famous Stanford Prison Experiment that has become a cornerstone of social psychology (PDF of review here).

The 1971 Stanford Prison Experiment, in which subjects (ordinary college-age men) were assigned to play the role of a prisoner or guard, demonstrated that situations may be more powerful than personality traits in affecting behavior. Subjects playing the role of guards in the Stanford Prison Experiment were quickly transformed into abusers. This scene eerily evokes the photos taken decades later by the guards at Abu Ghraib prison in Iraq.

A clip from the review:

What, Zimbardo asks, leads ordinary people to do bad things, things they never would have imagined doing? Most evildoing, it becomes depressingly clear, is driven by rather ordinary social-psychological reactions. Zimbardo offers an extensive list and discussion of the toxic situational forces and normal psychological reactions to them that tend to activate the Lucifer effect. He provides a detailed, intelligent and workable program for resisting unwanted social influence, highlighting dangers and offering tangible prescriptions for neutralizing negative effects. There are, for example, mini-tutorials on how to distinguish between just and unjust authorities, on being careful not to sacrifice one's freedom for the illusion of security, and on learning to recognize when, where and how to stand up to unjust systems.

The final chapter is a gem. Here Zimbardo seamlessly demonstrates how the same social psychology that may exploit our worst instincts can be reconstrued to cultivate the best in ourselves. Altruism, like evil, is readily responsive to situational forces, and Zimbardo suggests strategies for tapping into these potentialities. He also presents a provocative, multidimensional taxonomy of heroism that I hope will stimulate long-overdue research and education in this area.

Why Men Matter: Mating Patterns Drive Evolution of Human Lifespan

Tuljapurkar et al. present an interesting model for why human lifespan continues well past the age of menopause in women.. even though women no longer reproduce, older men still mate with younger women, and natural selection favors survival for as long as men reproduce (that is, there is a selective force against deleterious autosomal mutations at ages well past menopause). Here is their abstract, you should check the figures in the paper....

Evolutionary theory predicts that senescence, a decline in survival rates with age, is the consequence of stronger selection on alleles that affect fertility or mortality earlier rather than later in life. Hamilton quantified this argument by showing that a rare mutation reducing survival is opposed by a selective force that declines with age over reproductive life. He used a female-only demographic model, predicting that female menopause at age ca. 50 yrs should be followed by a sharp increase in mortality, a “wall of death.” Human lives obviously do not display such a wall. Explanations of the evolution of lifespan beyond the age of female menopause have proven difficult to describe as explicit genetic models. Here we argue that the inclusion of males and mating patterns extends Hamilton's theory and predicts the pattern of human senescence. We analyze a general two-sex model to show that selection favors survival for as long as men reproduce. Male fertility can only result from matings with fertile females, and we present a range of data showing that males much older than 50 yrs have substantial realized fertility through matings with younger females, a pattern that was likely typical among early humans. Thus old-age male fertility provides a selective force against autosomal deleterious mutations at ages far past female menopause with no sharp upper age limit, eliminating the wall of death. Our findings illustrate the evolutionary importance of males and mating preferences, and show that one-sex demographic models are insufficient to describe the forces that shape human senescence.
Male fertility in 1980 France (black), Pakistan 1984 (blue dots) and Cameroon 1964 (red dashes). Cameroon's distribution is common of high-fertility polygynous societies. The Y-axis shows age-specific fertility rates as a fraction of the total fertility rate.

Thursday, September 06, 2007

Chicago Art Institute - Garden Restaurant

I thought I would say hello from the middle of an annual mini-vacation to Chicago, staying with old friends and visiting the Art Institute.

More on "The Political Brain"

As a followup on my Oct. 23 and July 11 posts on neuroimaging during political decisions I would like to point out David Brooks' review of Westen's book "THE POLITICAL BRAIN - The Role of Emotion in Deciding the Fate of the Nation." He suggests that Westen - even granted that he does a convincing job of showing how emotions can color political decisions - goes overboard in essentially suggesting that appeals to rationality should be thrown out altogether.

Westen:

...assert(s) that Democrats have been losing because they have been appealing to the rational part of the mind. They issue laundry lists of policies and offer arguments with evidence. They don’t realize how the images they are presenting set off emotional cues that undermine their own campaigns...For example, the right side of John Edwards’s mouth tends to curl up. “Humans innately dislike facial asymmetries,” Westen observes, “and this should have caught the eye of his advisers.” In Connecticut, Ned Lamont ran a commercial showing Joe Lieberman morphing into George Bush, but in the ad Lieberman was smiling. “Smiling faces innately activate parts of the brain (and facial mimicry on the part of the observer) that reinforce happiness, not distaste.”..Republicans...,are brilliant at using words and images that set off emotional cascades. Ronald Reagan used the word “confiscation” in reference to taxation, and was able to persuade people to agree to lower taxes. He called Nicaraguan contras “freedom fighters” and was able to secure them funding.
Brooks suggests:
The core problem with Westen’s book is that he doesn’t really make use of what we know about emotion. He builds on the work of Antonio Damasio, without applying Damasio’s conception of how emotion emerges from and contributes to reason...In this more sophisticated view, emotions are produced by learning. As we go through life, we learn what cause leads to what effect. When, later on, we face similar situations, the emotions highlight possible outcomes, drawing us toward some actions and steering us away from others...In other words, emotions partner with rationality. It’s not necessary to dumb things down to appeal to emotions. It’s not necessary to understand some secret language that will key certain neuro-emotional firings. The best way to win votes — and this will be a shocker — is to offer people an accurate view of the world and a set of policies that seem likely to produce good results.

Discontinuities between Human and Animal Cognition

Premack offers a stimulating brief essay (PDF here) pointing out that recent cognitive studies finding abilities in animals once thought unique to humans should not lead us to confuse similarity with equivalence, for the human brain has nerve cell types and connections not found in any other animals. He examines eight cognitive areas to argue that dissimilarities are large. Here is his abstract:

Microscopic study of the human brain has revealed neural structures, enhanced wiring, and forms of connectivity among nerve cells not found in any animal, challenging the view that the human brain is simply an enlarged chimpanzee brain. On the other hand, cognitive studies have found animals to have abilities once thought unique to the human. This suggests a disparity between brain and mind. The suggestion is misleading. Cognitive research has not kept pace with neural research. Neural findings are based on microscopic study of the brain and are primarily cellular. Because cognition cannot be studied microscopically, we need to refine the study of cognition by using a different approach. In examining claims of similarity between animals and humans, one must ask: What are the dissimilarities? This approach prevents confusing similarity with equivalence. We follow this approach in examining eight cognitive cases—teaching, short-term memory, causal reasoning, planning, deception, transitive inference, theory of mind, and language—and find, in all cases, that similarities between animal and human abilities are small, dissimilarities large. There is no disparity between brain and mind.
Another major article on this topic is in draft form for Brain and Behavioral Sciences: "Darwin’s mistake: explaining the discontinuity between human and nonhuman minds," by Derek C. Penn, Keith J. Holyoak and Daniel J. Povinelli.
Their abstract:
Over the last quarter-century, the dominant tendency in comparative cognitive psychology has been to emphasize the similarities between human and nonhuman minds and to downplay the differences as “one of degree and not of kind” (Darwin 1871). In the present paper, we argue that Darwin was mistaken: the profound biological continuity between human and nonhuman animals masks an equally profound discontinuity between human and nonhuman minds. To wit, there is a significant discontinuity in the degree to which human and nonhuman animals are able to approximate the higher-order, systematic, relational capabilities of a physical symbol system (Newell 1980). We show that this symbolic-relational discontinuity pervades nearly every domain of cognition and runs much deeper than even the spectacular scaffolding provided by language or culture alone can explain. We propose a representational-level specification of where human and nonhuman animals’ abilities to approximate a PSS are similar and where they differ. We conclude by suggesting that recent symbolic-connectionist models of cognition shed new light on the mechanisms that underlie the gap between human and nonhuman minds.

Wednesday, September 05, 2007

Evolution of the upturned palm

Tierney writes a brief article in the Aug. 28 NYTimes science section on thinking about ancient origins of the "can you spare me a dime" upturned palm, noting that the upturned palm is a submissive gesture:

...a “gestural byproduct” of the circuits in the brain and spinal cord that protected vertebrates hundreds of millions of years ago..Confronted with a threat, ancient lizards would instinctively bend their spine and limbs to press their bodies closer to the ground, protecting the neck and head and signaling submission to a larger animal. This crouch display is the opposite of the high-stand display, the aggressive posture of a stallion or a gorilla raising its chest and head to appear larger...The human remnant of the crouch display is a shrug of the shoulders, which lowers the head and rotates the forearms outwards so that the palms face up. Conversely, the high-stand display persists in humans as a rotation of the forearms and palms in the opposite direction, producing the domineering palm-down gesture used by a boss slapping the conference table or an orator commanding quiet from his audience.
The Emory University group (Franz de Waal et al.) have found that Chimps and Bonobos use the palm-up gesture in a much more flexible way (depending on the situation and group) that vocalizations and facial expression (more strongly tied to emotions). This leads to speculation that gestures may have served as the steppingstone for early hominid communication and, possibly, language.

fMRI feedback for pain reduction

Jason Pontin discusses Omneuron and other start-ups that propose to teach sufferers to think away their pain...and... similarly treat addiction, depression and other intractable neurological and psychological conditions (PDF here).

Tuesday, September 04, 2007

Prokofiev Ballade for Cello and Piano

In this video Sonny Enslen (cello) and I are doing a final rehearsal before doing this piece for two amateur music performance groups in Madison Wisconsin: Carnaval and Allegro. The piano is a Steinway B at my Twin Valley, Middleton WI, home, freshly tuned and voiced.

Calisthenics for the aging mind.

I'll pass on this reasonably written NYTimes article by Christine Larson (PDF here) about software products promising brain enhancement for those of us who fret about our aging brains.

Permanent amygdala changes in people close to 9/11 attack

I'm passing on this brief piece pointed out to me by blog reader Scott Rosenblum, from Scientific American Mind. Readers will recall that the amygdala is the part of the brain that regulates emotional intensity and creates emotional memories. One clip:

In the Cornell study, functional magnetic resonance imaging (fmri) scans showed that people within two miles of the site that day have a hyperactive amygdala as compared with people who lived 200 miles away, even though those nearby were seemingly resilient and show no signs of mental disorder. The N.Y.U. team similarly found that when asked to recall the events of 9/11, twice as many people who were near Ground Zero had elevated amygdala activity as compared with people who were five miles away in midtown Manhattan. Slow recovery of a highly active amygdala, the Cornell researchers say, could increase susceptibility to mental health problems later in life.
By the way, Scientific American Mind is issued monthly, some of the brief articles you can read, others require a digital subscription (which I have been too stingy to spring for.)

Monday, September 03, 2007

The topography of fear

Mobbs and colleagues have devised an ingenious experiment to evaluate how different neural circuits in the human brain are engaged by distal and proximal threats. From the review of this work by Maren:

Mobbs and colleagues developed a computerized virtual maze in which subjects are chased and potentially captured by an "intelligent" predator. During the task, which was conducted during high-resolution functional magnetic resonance imaging (fMRI) of cerebral blood flow (which reflects neuronal activity), subjects manipulated a keyboard in an attempt to evade the predator. Although the virtual predator appeared quite innocuous (it was a small red circle), it could cause pain (low- or high-intensity electric shock to the hand) if escape was unsuccessful. Brain activation in response to the predatory threat was assessed relative to yoked trials in which subjects mimicked the trajectories of former chases, but without a predator or the threat of an electric shock....the prefrontal cortex and lateral amygdala were strongly activated when the level of threat was low, and this activation shifted to the central amygdala and periaqueductal gray when the threat level was high.

Models of consciousness at ASSC

By now I've made a number of references to the June 22-25 meeting of the Association for the Scientific Study of Consciousness in Las Vegas. Stuart Hameroff has just offered a report (PDF here) on the conference in the Journal of Consciousness Studies. His discussion of 'local' versus 'global' connection models of consciousness is worth excerpting here:

Dennett...reiterated one key feature of his multiple drafts model, that
activity anywhere in the brain could elicit consciousness, as long as
that particular activity was more than activity in any other brain area at
that moment. When asked precisely what type of neural activity did
the trick, Dennett passed. Put both Gazzaniga and Dennett in the ‘local’
camp (apparently with Christof Koch, who took that position in
last year’s ASSC debate). The globalists came later.

Koch (ASSC’s scientific compass) and most neuroscientists
assume axonal firings, or spikes are the bit-like currency underlying
the NCC. Gamma synchrony (coherent 30 to 90 Hz EEG, a.k.a.
‘coherent 40 Hz’) and other EEG are generated not by spikes, but by
dendritic local field potentials (LFPs), a distinction addressed in two
excellent posters from David Leopold’s NIMH group. Recording both
spikes and LFPs in monkey cortex and thalamus, they found that subjective
awareness correlates with dendritic LFPs rather than axonal
spikes.

Are dendrites and gamma synchrony outside ASSC’s narrow
focus? After Singer discovered gamma correlations with consciousness
in the 1980s, Francis Crick and Christof Koch helped launch the
gamma synchrony NCC bandwagon. But they later jumped ship,
along with many others, related to an influential analysis by Shadlen
and Movshon which rejected gamma synchrony. Gamma synchrony
was rejected not because it doesn’t correlate with consciousness — it
clearly does — but because it doesn’t jive with axonal spikes, the
anointed currency of the NCC. Gamma synchrony EEG derives from
LFPs, in turn derived from post-synaptic dendritic potentials. Forced
to choose between dendritic synchrony and axonal spikes as the NCC,
Shadlen and Movshon, Crick and Koch and many others chose spikes,
and ASSC followed. Too bad.

LFPs and gamma synchrony occur both locally and globally,
compatible with both local origin theories, and global/hierarchical
views like Global Workspace (GW) and HOT. With GW guru Bernie
Baars in the house, global hierarchies surfaced in the superb session
‘Cortical Networks and Conscious Awareness’ with Alumit Ishai
(Zurich), Rafael Malach (Israel) and Giulio Tononi (Wisconsin).

Tononi, more suave than even Koch, claimed that effective connectivity
(measurable through EEG/LFPs) in thalamocortical circuits
correlates with consciousness. Tononi used transcranial magnetic
stimulation on himself, among others, to see how it disrupted normal
sleep. (What an interesting college roommate he could have been!)
Put Tononi in the globalist camp.

Alumit Ishai used fMRI to study face recognition. She found
activity in a feed-forward (posterior to frontal) hierarchical network,
including posterior visual, limbic/emotional and frontal cortex. Put
Ishai in the globalist camp (along with Koch — now in both camps —
whose tutorial covered ‘top-down’, frontal to posterior, attention
mechanisms).

So … does consciousness require hierarchical organization as the
globalists and HOT proponents advocate? Or are the localists correct
in that consciousness can erupt in any sufficiently active brain region?
Rafael Malach from the Weizman Institute in Israel addressed this
issue. He studied continuous fMRI in subjects watching Sergio
Leone’s epic spaghetti Western The Good, the Bad and the Ugly,correlating
specific fMRI activity with precise movie scenes and frames.
While viewing the film, all above-baseline fMRI activity remained
posterior in the subjects’ visual cortical areas, with occasional snippets
of activity in sensory cortex. Malach showed that the appearance
of faces in the film (Clint Eastwood, Lee van Cleef, Eli Wallach) corresponded
with activity in viewers’ posterior visual cortex face
regions. Activity in the ‘hand’ area of sensory homunculi occurred
precisely during scenes/frames showing characters’ hands gripping a
gun, cigar or dealing cards.

Without posterior-frontal connections, Malach suggested lateral
links among basal dendrites of layer 5 pyramidal cells and cortical
interneurons worked in a distributed, rather than hierarchical,
LFP-friendly architecture to produce conscious experience. Put
Malach in his own camp — not local but not necessarily global. Call it
lateral/distributed.

Could local, global and/or lateral/distributed neuronal organizations
each support different modes of consciousness in different circumstances?
When we are passively engrossed in a film, brain activity
remains posterior, e.g. in Malach’s lateral/distributed scheme. When
we become introspective or engage in command-and-control modes,
frontal cortex kicks in and more global GW/HOT networks take over.
Very localized activity could also result in consciousness (e.g. Zeki’s
famous colour consciousness in isolated V4 activity, or Damasio’s or
Panksepp’s emotional core suggestions).

So the question becomes not so much where, but precisely what
type of neural activity distinguishes consciousness from unconscious
processes. The evidence points to synchronized dendritic LFPs rather
than axonal spikes. And if Block and Kouider are correct, neural
activities supporting unconscious processes must be further divided
into (at least) two sub-types: non-conscious and pre-conscious/
access. There’s plenty of need for lower level subtlety.