Cognitive Illusions

My son Jon pointed me to this engaging TED talk on cognitive illusions by Dan Ariely.

Genes to cognition

Here is an educational site you might enjoy checking out, supported by the Cold Spring Harbor Laboratory.

Attention training and attention state training

Tang and Posner (PDF here) examine two different approaches that have been shown to improve attention and self-regulation: computer based exercises in children and adults (attention training, AT); and exposure to nature, mindfulness and integrative body-mind training (IBMT, or attention state training, AST). Here is their summary of the characteristics of these two approaches:

AT
• Trains executive attention networks
• Requires directed attention and effortful control
• Targets non-autonomic control systems
• Produces mental fatigue easily
• Training transfers to other cognitive abilities

AST
• Produces changes of body-mind state
• Requires effortful control (early stage) and effortless exercise (later)
• Involves the autonomic system
• Aims at achieving a relaxed and balanced state
• Training transfers to cognition, emotion and social behaviors

Activation of the anterior cingulate cortex appears to be central with both approaches, with AT involving involving changes in anterior cingulate and lateral prefrontal areas, perhaps mainly through increased connectivity between the two. AST involves increased interaction between anterior cingulate cortex and the autonomic nervous system. Increase in activity in the ACC in AST is similar to what is found in AT during task performance and could account for the improved executive attention with both methods.

It is worth noting that both aerobic exercise (A.F. Kramer and K.I. Erickson, Capitalizing on cortical plasticity: influence of physical activity on cognition and brain function, Trends Cogn. Sci. 11 (2007), pp. 342–348) and music education (E.G. Schellenberg, Music and cognitive abilities, Psychol. Sci. 14 (2004), pp. 317–320.) have also been shown to enhance cognitive processes

Lucid old age.

Want to live past 90 without dementia? Check out this article by Benedict Carey describing a retirement community in Los Angeles.

Empathy Marketing 101

I pass on this interesting review on "neuromarketing" that Gary Ohlson has just emailed to me.

Stress pathways that impair prefrontal cortex.

Arnsten offers a focus article (one among several) in Nature Reviews Neuroscience that describes how stress impairs the top-down cognitive control functions of the prefrontal cortex, and enhances bottom-up amygdala-limbic emotional influences. I'm passing on the abstract and a summary figure with its text that might be useful for teaching:

The prefrontal cortex (PFC) — the most evolved brain region — subserves our highest-order cognitive abilities. However, it is also the brain region that is most sensitive to the detrimental effects of stress exposure. Even quite mild acute uncontrollable stress can cause a rapid and dramatic loss of prefrontal cognitive abilities, and more prolonged stress exposure causes architectural changes in prefrontal dendrites. Recent research has begun to reveal the intracellular signalling pathways that mediate the effects of stress on the PFC. This research has provided clues as to why genetic or environmental insults that disinhibit stress signalling pathways can lead to symptoms of profound prefrontal cortical dysfunction in mental illness.


The prefrontal cortex (PFC) has extensive connections with other cortical and subcortical regions that are organized in a topographical manner, such that regions that regulate emotion are situated ventrally and medially (green area in part a of the figure) and regions that regulate thought and action are situated more dorsally and laterally (blue and blue–green areas in part a). The dorsolateral PFC (DLPFC) has extensive connections with sensory and motor cortices and is key for regulating attention, thought and action1. In humans, the right inferior PFC (rIPFC) seems to be specialized for inhibiting inappropriate motor responses. By contrast, the ventromedial PFC (VMPFC) has extensive connections with subcortical structures (such as the amygdala, the nucleus accumbens and the hypothalamus) that generate emotional responses and habits and is thus able to regulate emotional responses. Finally, the dorsomedial PFC (DMPFC) has been associated with error monitoring9 and, in human functional MRI studies, reality testing. These PFC regions extensively interconnect to regulate higher-order decision making and to plan and organize for the future. Under non-stress conditions (see part a of the figure), the extensive connections of the PFC orchestrate the brain's activity for intelligent regulation of behaviour, thought and emotion. The PFCalso has direct and indirect connections to monoamine cell bodies in the brainstem, such as the locus coeruleus (LC) (where noradrenaline projections arise) and the substantia nigra (SN) and ventral tegmental area (VTA) (where the major dopamine projections originate), and thus can regulate its own catecholamine inputs. Optimal levels of catecholamine release in turn enhance PFC regulation, thus creating a 'delicious cycle'. Under conditions of psychological stress (see part b of the figure) the amygdala activates stress pathways in the hypothalamus and brainstem, which evokes high levels of noradrenaline (NA) and dopamine (DA) release. This impairs PFC regulation but strengthens amygdala function, thus setting up a 'vicious cycle'. For example, high levels of catecholamines, such as occur during stress, strengthen fear conditioning mediated by the amygdala. By contrast, stress impairs higher-order PFC abilities such as working memory and attention regulation. Thus, attention regulation switches from thoughtful 'top-down' control by the PFC that is based on what is most relevant to the task at hand to 'bottom-up' control by the sensory cortices, whereby the salience of the stimulus (for example, whether it is brightly coloured, loud or moving) captures our attention5. The amygdala also biases us towards habitual motor responding rather than flexible, spatial navigation. Thus, during stress, orchestration of the brain's response patterns switches from slow, thoughtful PFC regulation to the reflexive and rapid emotional responses of the amygdala and related subcortical structures.

Parietal brain neurons tuned to fractions

Interesting work from Jacob and Nieder:

Although the concept of whole numbers is intuitive and well suited for counting and ordering, it is with the invention of fractions that the number system gained precision and flexibility. Absolute magnitude is encoded by single neurons that discharge maximally to specific numbers. However, it is unknown how the ratio of two numbers is represented, whether by processing numerator and denominator in separation, or by extending the analog magnitude code to relative quantity. Using functional MRI adaptation, we now show that populations of neurons in human fronto-parietal cortex are tuned to preferred fractions, generalizing across the format of presentation. After blood oxygen level-dependent signal adaptation to constant fractions, signal recovery to deviant fractions was modulated parametrically as a function of numerical distance between the deviant and adaptation fraction. The distance effect was invariant to changes in notation from number to word fractions and strongest in the anterior intraparietal sulcus, a key region for the processing of whole numbers. These findings demonstrate that the human brain uses the same analog magnitude code to represent both absolute and relative quantity. Our results have implications for mathematical education, which may be tailored to better harness our ability to access automatically a composite quantitative measure.

More Chopin, the Polonaise No. 1

Here is a further piece I have recorded recently on my Steinway B at Twin Valley.

Liberals and Conservatives feel differently

Kristoff reviews evidence that our political stances start with flash moral intuitions that our brains then find evidence to support. For liberals, morality derives mostly from fairness and prevention of harm. For conservatives, morality places relatively more emphasis on upholding authority and loyalty — and revulsion at disgust.

Psychologists have developed a “disgust scale” based on how queasy people would be in 27 situations, such as stepping barefoot on an earthworm or smelling urine in a tunnel. Conservatives systematically register more disgust than liberals. (To see how you weigh factors in moral decisions, take the tests at http://yourmorals.org/.)...One experiment involved hypnotizing subjects to expect a flash of disgust at the word “take.” They were then told about Dan, a student council president who “tries to take topics that appeal to both professors and students.” The research subjects felt disgust but couldn’t find any good reason for it. So, in some cases, they concocted their own reasons, such as: “Dan is a popularity-seeking snob.”

Hugs

Given the unhealthy phobia about physical contact in this country, in addition to litigious paranoia about sexual harassment or improper touching, I was really heartened to read this account of a new trend among teenagers in high school of giving hugs on greeting: male-female, female-female, even male-male (given sanction by recent 'Bromance' movies). Some prune faced administrators have banned it, but I think it reflects that kids are more inclined to nuture each other, perhaps as an antidote to comparative aridity of a world of Facebook 'friends.' (By the way, I wrote this brief post on reading the NYTimes article yesterday morning, then set it to be actually posted next Monday. Then I see the bloody story featured on the NBC Evening News yesterday evening, interviews with experts and all that, and so I guess I have to stay with the news cycle and post while its fresh!).

The coming superbrain?

John Markoff offers a timely essay - given the recent release of the movie "Terminator Salvation" - on the future of artificial intelligence. There seems to be little doubt that we will eventually be able to design machines that have the emergent property, like ourselves, of being aware of their own internal states. Metzinger suggests that this will happen once the neural underpinnings of his "Ego Tunnel" are made more clear.

Your own brain gym.

Passing on this link emailed to me this morning: Build Your Own Brain Gym: 100 Tools, Exercises, and Games. The blog on this website (which, curiously, is a health care administration career site) contains a veritable orgy of self-help links.

Subcortical enhancement of musical intervals in musicians

From Lee et al:

By measuring the auditory brainstem response to two musical intervals, the major sixth (E3 and G2) and the minor seventh (E3 and F#2), we found that musicians have a more specialized sensory system for processing behaviorally relevant aspects of sound. Musicians had heightened responses to the harmonics of the upper tone (E), as well as certain combination tones (sum tones) generated by nonlinear processing in the auditory system. In music, the upper note is typically carried by the upper voice, and the enhancement of the upper tone likely reflects musicians' extensive experience attending to the upper voice. Neural phase locking to the temporal periodicity of the amplitude-modulated envelope, which underlies the perception of musical harmony, was also more precise in musicians than nonmusicians. Neural enhancements were strongly correlated with years of musical training, and our findings, therefore, underscore the role that long-term experience with music plays in shaping auditory sensory encoding.

The amusic brain

Peretz et al. find that people with congenital amusia (~4% of the population unable to distinguish different tones) have the essential neural circuitry to perceive fine-grained pitch differences, but limited awareness of this ability and the lack of responsiveness to semitone changes that violate musical keys. Apparently the neural pitch representation cannot make contact with musical pitch knowledge along the auditory-frontal neural pathway.

Like language, music engagement is universal, complex and present early in life. However, ~4% of the general population experiences a lifelong deficit in music perception that cannot be explained by hearing loss, brain damage, intellectual deficiencies or lack of exposure. This musical disorder, commonly known as tone-deafness and now termed congenital amusia, affects mostly the melodic pitch dimension. Congenital amusia is hereditary and is associated with abnormal grey and white matter in the auditory cortex and the inferior frontal cortex. In order to relate these anatomical anomalies to the behavioural expression of the disorder, we measured the electrical brain activity of amusic subjects and matched controls while they monitored melodies for the presence of pitch anomalies. Contrary to current reports, we show that the amusic brain can track quarter-tone pitch differences, exhibiting an early right-lateralized negative brain response. This suggests near-normal neural processing of musical pitch incongruities in congenital amusia. It is important because it reveals that the amusic brain is equipped with the essential neural circuitry to perceive fine-grained pitch differences. What distinguishes the amusic from the normal brain is the limited awareness of this ability and the lack of responsiveness to the semitone changes that violate musical keys. These findings suggest that, in the amusic brain, the neural pitch representation cannot make contact with musical pitch knowledge along the auditory-frontal neural pathway.

The management of our attention

Here is another of the many nuggets (from Chapter 9) from Metzinger's new book that hit me as an excellent summary. He discusses the problem we face in the management of our attention:

The ability to attend to our environment, to our own feelings, and to those of others is a naturally evolved feature of the human brain. Attention is a finite commodity, and it is absolutely essential to living a good life. We need attention in order to truly listen to others - and even to ourselves. We need attention to truly enjoy sensory pleasures, as well as for efficient learning. We need it in order to be truly present during sex or to be in love or when we are simply contemplating nature. Our brains can generate only a limited amount of this precious resource every day.

Today, the advertisement and entertainment industries are attacking the very foundations of our capacity for experience, drawing us into the vast and confusing media jungle. They are trying to rob us of as much of our scarce resource as possible, and they are doing so in every more persistent and intelligent ways. Of course, they are increasingly making use of the new insights in the human mind offered by cognitive and brain science to achieve their goals ("neuromarketing" is one of the ugly new buzzwords). We can see the probable result in the epidemic of attention-deficit disorder in children and young adults, in midlife burnout, in rising levels of anxiety in large parts of the population. If I am right that consciousness is the space of attentional agency, and if (as discussed in chapter 4) it is also true that the experience of controlling and sustaining your focus of attention is one of the deeper layers of phenomenal selfhood, then we are currently witnessing not only an organized attack on the speace of consciousness per se but a mild form of depersonalization. New medial environments many create a new form of waking consciousness that resembles weakly subjective states - a mixture of dreaming, dementia, intoxication, and infantilization.

Having just forced myself to watch the recent American Idol show climax, these points have struck me as particularly cogent. Metzinger suggests we counter the attacks on our reserves of attention by introducing classes in meditation in our high schools, by making the young aware of our limited capacity for attention, and the need to learn techniques to sustain it and enhance mindfulness.

Semantic versus behavioral deficits in left versus right fronto-temporal lobe atrophies

Chan et al. provide a survey of the deficits observed in people with left versus right fronto-temporal lobe atrophies, which cause, respectively mainly semantic (left) versus behavioral (right) disorders. Their summary:

Frontotemporal lobar degeneration is currently associated with three syndromic variants. Disorders of speech and language figure prominently in two of the three variants, and are associated with left-sided frontotemporal atrophy. The detailed characterization of these syndromes contrasts with the relative paucity of information relating to frontotemporal lobar degeneration primarily affecting the right cerebral hemisphere. The objective of this study was to identify the clinical profile associated with asymmetrical, predominantly right-sided, temporal lobe atrophy. Twenty patients with predominant right temporal lobe atrophy were identified on the basis of blinded visual assessment of the MRI scans. The severity of right temporal lobe atrophy was quantified using volumetric analysis of the whole temporal lobes, the amygdala and the hippocampus. Profiles of cognitive function, behavioural and personality changes were obtained on each patient. The pattern of atrophy and the clinical features were compared with those observed in a group of patients with semantic dementia and predominant left-sided temporal lobe atrophy. The mean right temporal lobe volume in the right temporal lobe atrophy group was reduced by 37%, with the mean left temporal lobe volume reduced by 19%. There was marked atrophy of the right hippocampus and right amygdala, with mean volumes reduced by 41 and 51%, respectively (left hippocampus and amygdala volumes were reduced by 18 and 33%, respectively). The most prominent cognitive deficits were impairment of episodic memory and getting lost. Prosopagnosia was a symptom in right temporal lobe atrophy patients. These patients also exhibited a variety of behavioural symptoms including social disinhibition, depression and aggressive behaviour. Nearly all behavioural disorders were more prevalent in the right temporal lobe atrophy patient group than the semantic dementia group. Symptoms particular to the right temporal lobe atrophy patient group included hyper-religiosity, visual hallucinations and cross-modal sensory experiences. The combination of clinical features associated with predominant right temporal lobe atrophy differs significantly from those associated with the other syndromes associated with focal degeneration of the frontal and temporal lobes and it is, therefore, proposed that this right temporal variant should be considered a separate syndromic variant of frontotemporal lobar degeneration.

A musical offering for this week - Chopin Nocture in C minor

Here is the posthumous Chopin Nocture in C minor.

Neural correlates of vicarious reward.

Interesting observations from Mobbs et al. The experiments involved brain imaging of participants reacting to game winning by contestants with whom they were or were not sympathetic. Their abstract (slightly edited):

Humans appear to have an inherent prosocial tendency toward one another in that we often take pleasure in seeing others succeed. This fact is almost certainly exploited by game shows, yet why watching others win elicits a pleasurable vicarious rewarding feeling in the absence of personal economic gain is unclear. One explanation is that game shows use contestants who have similarities to the viewing population, thereby kindling kin-motivated responses (for example, prosocial behavior). Using a game show–inspired paradigm, we show that the interactions between the ventral striatum and anterior cingulate cortex subserve the modulation of vicarious reward by similarity, respectively. Our results support studies showing that similarity acts as a proximate neurobiological mechanism where prosocial behavior extends to unrelated strangers.

Evidence for separate semantic and syntactic processing in deaf native signers.

Adding to evidence from written and spoken language suggesting that nonidentical brain networks support semantic and syntactic processing, Capek et al now find a similar distinction in native deaf signers:

Studies of written and spoken language suggest that nonidentical brain networks support semantic and syntactic processing. Event-related brain potential (ERP) studies of spoken and written languages show that semantic anomalies elicit a posterior bilateral N400, whereas syntactic anomalies elicit a left anterior negativity, followed by a broadly distributed late positivity. The present study assessed whether these ERP indicators index the activity of language systems specific for the processing of aural-oral language or if they index neural systems underlying any natural language, including sign language. The syntax of a signed language is mediated through space. Thus the question arises of whether the comprehension of a signed language requires neural systems specific for this kind of code. Deaf native users of American Sign Language (ASL) were presented signed sentences that were either correct or that contained either a semantic or a syntactic error (1 of 2 types of verb agreement errors). ASL sentences were presented at the natural rate of signing, while the electroencephalogram was recorded. As predicted on the basis of earlier studies, an N400 was elicited by semantic violations. In addition, signed syntactic violations elicited an early frontal negativity and a later posterior positivity. Crucially, the distribution of the anterior negativity varied as a function of the type of syntactic violation, suggesting a unique involvement of spatial processing in signed syntax. Together, these findings suggest that biological constraints and experience shape the development of neural systems important for language.

Massage stimulates brain development

I've always been a massage nut. Many years ago I had some formal training, and I always feel totally rejuvenated by the too-infrequent massages I occasionally get. This item in the Journal of Neuroscience from Guzzetta et al. makes perfect sense to me. I'll bet that a shadow of these early effects of massage seen in infants still occur in adults. The brain growth factor (IGF-1) enhanced by massage in infants is also associated with brain plasticity in adult humans:

Environmental enrichment (EE) was shown recently to accelerate brain development in rodents. Increased levels of maternal care, and particularly tactile stimulation through licking and grooming, may represent a key component in the early phases of EE. We hypothesized that enriching the environment in terms of body massage may thus accelerate brain development in infants. We explored the effects of body massage in preterm infants and found that massage accelerates the maturation of electroencephalographic activity and of visual function, in particular visual acuity. In massaged infants, we found higher levels of blood IGF-1. Massage accelerated the maturation of visual function also in rat pups and increased the level of IGF-1 in the cortex. Antagonizing IGF-1 action by means of systemic injections of the IGF-1 antagonist JB1 blocked the effects of massage in rat pups. These results demonstrate that massage has an influence on brain development and in particular on visual development and suggest that its effects are mediated by specific endogenous factors such as IGF-1.