Deric's MindBlog on vacation in the UK.

I've just arrived in London on my second trip of the summer: 16 days in the UK, first staying at a friend's flat near the Baker St. station, then with my partner in a Univ. of Wisconsin colleague's house in Hagley, just west of Birmingham. Deric Bownds' MindBlog will be taking a break unless I find myself in the mood to do some posts during the trip.

Taking turns in conversations - universals and cultural variation

Stivers et al. examine the frequent claims in anthropological literature that cultures differ radically in the timing of conversational turn-taking (e.g. Nordic cultures as slow, New York Jewish culture as fast):

Informal verbal interaction is the core matrix for human social life. A mechanism for coordinating this basic mode of interaction is a system of turn-taking that regulates who is to speak and when. Yet relatively little is known about how this system varies across cultures. The anthropological literature reports significant cultural differences in the timing of turn-taking in ordinary conversation. We test these claims and show that in fact there are striking universals in the underlying pattern of response latency in conversation. Using a worldwide sample of 10 languages drawn from traditional indigenous communities to major world languages, we show that all of the languages tested provide clear evidence for a general avoidance of overlapping talk and a minimization of silence between conversational turns. In addition, all of the languages show the same factors explaining within-language variation in speed of response. We do, however, find differences across the languages in the average gap between turns, within a range of 250 ms from the cross-language mean. We believe that a natural sensitivity to these tempo differences leads to a subjective perception of dramatic or even fundamental differences as offered in ethnographic reports of conversational style. Our empirical evidence suggests robust human universals in this domain, where local variations are quantitative only, pointing to a single shared infrastructure for language use with likely ethological foundations.

The "Neuro Revolution"

German cognitive scientist and writer Stephan Schleim writes a review (download here) that is appropriately critical of Zack Lynch's new spiel "The Neuro Revolution: How Brain Science Is Changing Our World."

Some midweek Chopin - a Polonaise

Mapping the human brain "connectome"

It seems that almost everything can come now with an "-ome" suffix (referring to a totality of some sort. Beyond the original "genome" we now have a long list, including the proteome, speechome, mechanome, etc.). A massive project to establish a human brain connectome, or map of all brain connections, has just received a 30 million dollar cash infusion from the N.I.H. This is an unbelievably daunting task, Over the past century, neuroscientists have used three main sets of anatomical approaches to study neural connectivity: single-cell impregnation, optically based tract-tracing and electron microscopy. More recent techniques involve attaching color markers to intrinsic neuronal labels (shown in figure). Resolution at the electron microscope level, so far done only for the small nervous system of the nematode roundworm, is still technically inaccessible, so that the work will actually be on lower resolution of nerve tracts. But... I wonder then about the minor detail that no two human brains are the same. Even the brains of identical twins have been shown to differ significantly in their activation patterns and connectivity. (The same variability also confounds comparative genome studies.) While it will indeed be exciting, as it was for the human genome, to be told "We now have the first human brain connectome," an awesome amount of work then must follow.

Science Tattoos

An amazing gallery of what people will do to themselves (in the name of science?).

The cognitive neuroscience of dyslexia and its repair

John Gabrieli offers a review article in the July 17 issue of Science. Several clips:

Reading is essential in modern societies, but many children have dyslexia, a difficulty in learning to read. Dyslexia often arises from impaired phonological awareness, the auditory analysis of spoken language that relates the sounds of language to print. Behavioral remediation, especially at a young age, is effective for many, but not all, children. Neuroimaging in children with dyslexia has revealed reduced engagement of the left temporo-parietal cortex for phonological processing of print, altered white-matter connectivity, and functional plasticity associated with effective intervention. Behavioral and brain measures identify infants and young children at risk for dyslexia, and preventive intervention is often effective. A combination of evidence-based teaching practices and cognitive neuroscience measures could prevent dyslexia from occurring in the majority of children who would otherwise develop dyslexia.


Brain activation differences in dyslexia and its treatment. Functional magnetic resonance imaging activations shown on the left hemisphere for phonological processing in typically developing readers (left), age-matched dyslexic readers (middle), and the difference before and after remediation in the same dyslexic readers (right). Red circles identify the frontal region, and blue circles identify the temporo-parietal region of the brain. Both regions are hypoactivated in dyslexia and become more activated after remediation.

Brain changes from childhood to young adulthood

Supekar et al. compare large scale brain functional networks in 7-9 and 19-22 year olds and find that they differ significantly in hierarchical organization and interregional connectivity. Subcortical areas are more strongly connected with primary sensory, association, and paralimbic areas in children, whereas young-adults show stronger cortico-cortical connectivity between paralimbic, limbic, and association areas.

National Institutes of Health to be run by a religionist??

Sam Harris doesn't like the idea. Neither do I.

For a mellow start to the week - a Grieg Nocturne

Reason, emotion, and decision-making

Steven Quartz does an opinion piece in Trends in Cognitive Science noting that the tidy separation of our decision making into cognitive and emotional components is not appropriate. Two slightly edited clips:

Many models of judgment and decision-making (JDM) posit distinct cognitive and emotional contributions to decision-making under uncertainty. Cognitive processes typically involve exact computations according to a cost-benefit calculus, whereas emotional processes typically involve approximate, heuristic processes that deliver rapid evaluations without mental effort. However, it remains largely unknown what specific parameters of uncertain decision the brain encodes, the extent to which these parameters correspond to various decision-making frameworks, and their correspondence to emotional and rational processes. A review of basic research suggests that emotional processes encode in a precise quantitative manner the basic parameters of financial decision theory, indicating a reorientation of emotional and cognitive contributions to risky choice.

Despite the popularity and commonsense appeal of distinguishing between cognitive and emotional contributions to JDM, many fundamental issues remain unresolved. Theories can be characterized in terms of the representations and the computations over those representations they posit, and it remains unclear in what ways cognitive and emotional contributions to JDM differ along these dimensions. That is, at the level of representation, what specific parameters of uncertain decision contexts are encoded by the brain, to what extent do such representations correspond to the parameters of various decision-making frameworks, and to what extent do putatively distinct cognitive and emotional contributions to JDM correspond to distinct underlying representations of uncertain decision contexts? Addressing these issues poses several challenges, not least that competing theories are not behaviorally distinguishable. This suggests that adjudicating among different theories requires neural studies that use quantitative and parametric frameworks with suitable resolution to distinguish among the main parameters of these various models and disassociating the representation of their basic parameters from other potential components of uncertain choice, including learning, motivation and salience. Based on recent work using such experimental designs, I suggest that putative distinctions between cognitive and emotional contributions to JDM at the level of representation collapse. Emerging evidence suggests that emotional contributions to JDM do not encode approximate, heuristic evaluations. Rather, it suggests that emotional processes encode the precise, mathematically defined parameters of traditionally cognitive accounts of decision-making from economics and related fields, such as finance. On a more general note, such findings indicate that once-considered basic distinctions, such as that between cognition and emotion, do not map seamlessly onto brain functioning. That is, just as studies of the deep interconnectivity among emotional and cognitive structures suggests that assigning cognitive or emotional specialization to structures is deeply problematic, proposed functional distinctions, such as complexity differences between emotional and cognitive representations and computations, are likewise problematic.

The unconscionable rip-offs of American cell phone companies

Have an iPhone and fume at AT&T? Get furious over listening to Verizon's long introduction before you can leave a message? (They make 850 million a year by forcing us to sit there and wait).. Pogue writes a nice summary of your frustrations. Also, I can't resist passing on this New Yorker cartoon on the iPhone (click on the cartoon to enlarge it).

Training our minds to move matter

We know that our body schema is plastic (see recent post on this), and that our brain's motor routines can learn stable habits of controlling tools and prostheses as if they were our own actual body parts. Ganguly and Carmena have now taken the obvious step of pairing stable recordings from ensembles of primary motor cortex neurons in macaque monkeys with a constant decoder that transforms neural activity to prosthetic movements. Blakeslee points out that this work suggests that learning to move a computer cursor or robotic arm with nothing but thoughts can be no different from learning how to play tennis or ride a bicycle. The brain can form a motor memory to control a disembodied device in a way that mirrors how it controls its own body. Here is their summary, followed by an illustration:

Brain–machine interfaces (BMIs) have the potential to revolutionize the care of neurologically impaired patients. Numerous studies have now shown the feasibility of direct “brain control” of a neuroprosthetic device, yet it remains unclear whether the neural representation for prosthetic control can become consolidated and remain stable over time. This question is especially intriguing given the evidence demonstrating that the neural representation for natural movements can be unstable: BMIs provide a window into the plasticity of cortical circuits in awake-behaving subjects. Here, we show that long-term neuroprosthetic control leads to the formation of a remarkably stable cortical map. Interestingly, this map has the putative attributes of a memory trace, namely, it is stable across time, readily recalled, and resistant to the storage of a second map. The demonstration of such a cortical map for prosthetic control indicates that neuroprosthetic devices could eventually be controlled through the effortless recall of motor memory in a manner that mimics natural skill acquisition and motor control.


Schematics for manual control (MC) and brain control (BC). During MC, the animal physically performs a two-dimensional center-out task using the right upper extremity while the neural activity is recorded. Under BC, the animal performs a similar center-out task using a computer cursor under direct neural control through a decoder trained during MC.

Why I take an omega-3 supplement before bedtime...

I'm into dietary supplements that might be relevant to aging (as in the previous posts on resveratrol), and so thought this study was interesting, along with this summary from Rabin. (By the way, the 'before bedtime' in the title is chosen because we know that significant renewal and turnover of brain nerve cells membranes - whose fluidity is modulated by omega-3 content - occurs during sleep.)

Cortical thickness, MRI, and early Alzheimer's diagnosis

Alongside today's brief post on diet and aging, I thought I would pass on the links to two open access articles in the neurology journal "Brain." The first deals with early diagnosis of Alzheimer's disease using cortical thickness, and the second uses automated MRI measurements to identify individuals with mild cognitive impairment and Alzheimer's disease. (And, I suppose this is a good post in which to act on a request that I provide a link to Caring.com, "a website dedicated to helping people take care of their aging parents and other loved ones.")

Thursday morning Grieg, a Berceuse

I just looked up what a Berceuse is.... it's a lullaby, or soothing composition... This version would have to be considered a fairly robust rendering of the style.

Positive self statements: power for some, peril for others

Wood et al. offer an interesting article in Psychological Science. They present experiments showing that positive self-statements have the potential to make one feel worse if they lie outside one's latitude of acceptance, are self-discrepant and thereby highlight one's failures to meet one's standards, and arouse self-verification motives. Positive self-statements are especially likely to backfire for the very people they are meant to benefit: people with low self-esteem. Such people, by definition, see themselves as failing to meet standards in more domains or in more important domains than do people with high self-esteem. Moreover, self-verification motives should bias people with low self-esteem to reject positive self-statements, but encourage people with high self-esteem to accept them. Here is their abstract:

Positive self-statements are widely believed to boost mood and self-esteem, yet their effectiveness has not been demonstrated. We examined the contrary prediction that positive self-statements can be ineffective or even harmful. A survey study confirmed that people often use positive self-statements and believe them to be effective. Two experiments showed that among participants with low self-esteem, those who repeated a positive self-statement ("I'm a lovable person") or who focused on how that statement was true felt worse than those who did not repeat the statement or who focused on how it was both true and not true. Among participants with high self-esteem, those who repeated the statement or focused on how it was true felt better than those who did not, but to a limited degree. Repeating positive self-statements may benefit certain people, but backfire for the very people who "need" them the most.

Masturbation in the animal kingdom

An interesting piece by Engber from Slate Magazine (The article even includes a link to a YouTube gallery on the subject!):

The recent finding that masturbation improves the quality of human sperm supports the notion that it's an evolved trait and not merely a byproduct of our physiology. According to a branch of evolutionary theory called "sperm competition" that developed in the late-1960s, natural selection can produce just such a change in reproductive behavior. The theory focuses on polyandrous species—i.e., those in which a single female takes multiple partners and the sperm from several potential fathers might end up competing to fertilize the same egg. Under those conditions, the relative quality of male ejaculate very clearly determines whose genes are passed on to the next generation.

So....this is how my cat is manipulating me

If you are a cat person, check out this interesting bit from Gisela Telis (it is open access for the new few weeks). She discusses a new study that reports that our feline friends modify their signature sound when seeking food, adding a higher-frequency element that exploits our sensitivity to infant wails-- thus making it harder to ignore. The article has some sound clips of the effect.

Rapamycin - a midlife longevity drug?

From the Nature 'Editor's Summary' of the paper by Harrison et al.

The antitumour drug rapamycin targets TOR, a kinase that is part of the PI3K–AKT–mTOR cascade, involved in regulating protein translation, cell growth and autophagy. Reducing TOR function is known to extend the life of yeast, worms and flies. Now experiments replicated in three different laboratories demonstrate that rapamycin, fed to male and female mice in a dose that substantially inhibits TOR signalling, can extend their median and maximal lifespan by up to 14%. This life extension was observed in mice fed rapamycin from 270 days of age and also at a late stage in their life, from age 600 days. These findings point to the TOR pathway as a critical point in the control of ageing in mammals and in the pathogenesis of late-life illnesses.