An informative genetic grammatical impairment - the biological basis of language

A fascinating article from van der Lely and Pinker:

•Specific language impairment is a heterogeneous family of genetic developmental disorders that affects the acquisition of language in 7% of children. 

•We have identified a subtype, Grammatical-SLI, which affects the children's syntax, morphology, and phonology in similar ways. 

•Grammatical abilities are not impaired across the board: the children handle forms that are local, linear, semantic, and holistic, while stumbling on those that are nonlocal, hierarchical, abstract, and composed. 

•The mosaic of impaired and spared abilities is consistent with new models of the neural bases of syntax, morphology, and phonology which distinguish several dorsal and ventral language pathways in the brain. 

•We foresee substantial progress in the biology of language – evolution, genetics, neurobiology, computation, behavior – if language and language impairments are differentiated into underlying pathways and components.

Specific language impairment (SLI), a genetic developmental disorder, offers insights into the neurobiological and computational organization of language. A subtype, Grammatical-SLI (G-SLI), involves greater impairments in ‘extended’ grammatical representations, which are nonlocal, hierarchical, abstract, and composed, than in ‘basic’ ones, which are local, linear, semantic, and holistic. This distinction is seen in syntax, morphology, and phonology, and may be tied to abnormalities in the left hemisphere and basal ganglia, consistent with new models of the neurobiology of language which distinguish dorsal and ventral processing streams. Delineating neurolinguistic phenotypes promises a better understanding of the effects of genes on the brain circuitry underlying normal and impaired language abilities.

The article contains some very useful summary graphics describing language areas and their interactions (click to enlarge):

Legend - Neural correlates of Extended and Basic syntax. Syntactic processing in the brain is implemented in distinct dorsal and ventral circuits which may correspond to Extended and Basic syntax. The dorsal route (unbroken red arrow) links Brodmann Area 44 (BA44, a part of Broca's area) via the arcuate fasciculus to the posterior superior temporal gyrus (STG, a part of Wernicke's area); this pathway has been implicated in complex syntactic processing, including hierarchical phrase structure and movement, that is, Extended syntax. The caudate nucleus of the basal ganglia (not shown), a subcortical structure, is interconnected with frontal cortex, and it has also been found to affect Extended syntax. The first of the two ventral circuits (blue arrow) links the frontal operculum (FO, the cortex inferior and medial to BA 44 and 45, mostly hidden) via the uncinate fasciculus to the anterior STG; it supports local phrase structure. The second (purple arrow) links Brodmann Areas 45 (BA45, another part of Broca's Area) and 47 via the extreme capsule fiber system to the middle portion of the superior and middle temporal lobe; it supports retrieval of stored words and associated semantic processing. The two ventral pathways, therefore, may correspond to Basic syntactic processing. Abbreviations: MTG, middle temporal gyrus; ITG, inferior temporal gyrus.

Legend - Neural correlates of Extended and Basic morphology. Regular inflectional forms (walked, played) are computed by Extended processes that closely overlap with those underlying Extended syntax, namely BA 45 extending into BA 44 and BA47, the arcuate fasciculus, and the superior and middle temporal cortex. The frontal regions are part of a circuit that also includes the caudate nucleus (not shown). In contrast, the storage and retrieval of irregular forms (‘brought’, ‘went’) appears to be mediated bilaterally (blue outline) in a more diffuse set of posterior and middle temporal lobe structures. Derived morphological forms, both regular (‘bravely’) and irregular (‘archer’), activate a third, bilateral network, which we tentatively associate with the ventral pathway, specifically, BA47 extending into BA45, and the anterior superior temporal gyrus (STG) and middle temporal gyrus (MTG) (purple lines). This network may support a network of related but whole word forms. Individuals with G-SLI are impaired in productive regular inflection, an Extended process that engages the dorsal route, but their performance is less impaired with the retrieval of irregular and derived forms, a Basic process which is more tried to lexical memory, and which engages bilateral ventral and posterior routes.

Legend - Neural correlates of Extended and Basic phonology. Phonological processing begins with spectrotemporal and segmental processing in bilateral auditory cortex (superior temporal gyrus, STG, and superior temporal sulcus, STS; right hemisphere not shown). From there it splits into two streams. A left-hemisphere dorsal stream runs to a sensorimotor integration area in the Sylvian portion of the parietal–temporal junction (SPT), and from there further bifurcates into a pathway along the superior longitudinal fasciculus to premotor areas (PM; pink arrow) and a pathway along the arcuate fasciculus to Broca's area (BA44; red arrow). These pathways connect acoustic speech representations to articulatory ones, the former perhaps to basic articulatory phonetic skills, the latter to complex syllables and words, self-monitoring speech, and verbal working memory. A bilateral ventral stream (right hemisphere portion not shown) runs from auditory cortex to the middle and inferior temporal gyri (MTG and ITG), and from there to the anterior temporal lobe, and also to a conceptual network widely distributed through the temporal and other lobes. This pathway connects the sounds of words to their meanings. We suggest that the Extended phonology which challenges G-SLI is associated with the part of the dorsal pathway that runs to Broca's area (red), but perhaps not the part that runs to premotor areas (pink), as articulation in the syndrome is relatively unimpaired. Basic phonology is associated with acoustic and phonological analysis in auditory cortex and with the ventral pathway.

Psilocybin as a key to consciousness.

Michael Pollan offers an engaging article "The Trip Treatment" in the Feb. 9 issue of The New Yorker magazine that describes the resurgence of interest and research on psychotropics like psilocybin, particularly their use in ameliorating end of life anxiety and stress. He points to interesting work by Carhart-Harris and collaborators that I wish I had been paying more attention to. Their article on the effects of psilocybin and MDMA on the resting state functional connectivity (RSFC) between different resting state networks (RSNs) describes experiments showing that psilocybin increases RSFC, making brain networks less differentiated from each other in the psychedelic state, decreasing the natural distinction between externally-focused attention (task positive networks) and introspection (default mode network). The idea is that this de-differentiation of brain networks, this transient disorganizing of brain activity, underlies mystical experiences such as feelings of unity, ineffability, sacredness, peace and joy, transcending space and time, sacredness, or finding some objective truth about reality.

What I would particularly point MindBlog readers to in this open source article is the excellent graphics depictions of Resting State Networks and their functional associations (visual, auditory, sensorimotor, default mode, executive control, dorsal attentional, etc.), and the illustration of marked increases in between-network RSFC under psilocybin.

I should point also to their more general theory of conscious states informed by neuroimaging research with psychedelics, which they term "The entropic brain hypothesis." Here is their summary graphic:

Spectrum of cognitive states. This schematic shows an “inverted u” relationship between entropy and cognition such that too high a value implies high flexibility but high disorder, whereas too low a value implies ordered but inflexible cognition. It is proposed that normal waking consciousness inhabits a position that is close to criticality but slightly sub-critical and primary states move brain activity and associated cognition toward a state of increased system entropy i.e., brain activity becomes more random and cognition becomes more flexible. It is proposed that primary states may actually be closer to criticality proper than secondary consciousness/normal waking consciousness.

A sense of the unfolding digital age.

I've just spent an hour following web links in the New York Times article on a recent course offered by recently deceased media columnist David Carr. The syllabus for Press Play, published on the blogging platform Medium, is a rich trove of pointers to articles describing the rise of more media rich chunks in the "Stream of Now" on mobile platforms and the decline of traditional web pages and blogging platforms such as Blogger, the one generating this post. This fuddy-duddy retired professor is feeling a bit left behind in the dust, but still not inclined to leap into the stream at the full velocity that 20-40 somethings seem to be managing!

Music training offsets decline in speech recognition on aging.

From Bidelman and Alain:

Musicianship in early life is associated with pervasive changes in brain function and enhanced speech-language skills. Whether these neuroplastic benefits extend to older individuals more susceptible to cognitive decline, and for whom plasticity is weaker, has yet to be established. Here, we show that musical training offsets declines in auditory brain processing that accompanying normal aging in humans, preserving robust speech recognition late into life. We recorded both brainstem and cortical neuroelectric responses in older adults with and without modest musical training as they classified speech sounds along an acoustic–phonetic continuum. Results reveal higher temporal precision in speech-evoked responses at multiple levels of the auditory system in older musicians who were also better at differentiating phonetic categories. Older musicians also showed a closer correspondence between neural activity and perceptual performance. This suggests that musicianship strengthens brain-behavior coupling in the aging auditory system. Last, “neurometric” functions derived from unsupervised classification of neural activity established that early cortical responses could accurately predict listeners' psychometric speech identification and, more critically, that neurometric profiles were organized more categorically in older musicians. We propose that musicianship offsets age-related declines in speech listening by refining the hierarchical interplay between subcortical/cortical auditory brain representations, allowing more behaviorally relevant information carried within the neural code, and supplying more faithful templates to the brain mechanisms subserving phonetic computations. Our findings imply that robust neuroplasticity conferred by musical training is not restricted by age and may serve as an effective means to bolster speech listening skills that decline across the lifespan.

MindBlog experiments with a brain enhancer.

I have done two previous posts on my personal experiments with compounds meant to promote longevity or vitality. The first dealt with resveratrol, a potential anti-aging compound. The second involved enhancers of energy production in the mitochondria of our body cells studied by the noted biochemist Bruce Ames (Acetyl L-carnitine, alpha-lipoic acid, biotin). In both cases I initially experienced some positive positive changes in energy and temperament, but after a few days unpleasant side effects led me to terminate the experiment. (Resveratrol caused arthritic symptoms, and the energy generated by N-acetyl l-carnitine and other components was more than I could handle, and expressed as agitation and nervousness.)

In this post I report my experience with one commercially available Nootropic (brain enhancing) mixture marketed by TruBrain,  whose main component is a daily dosage of 4 grams of piracetam (see below). The product is meant to promote cognitive focus in a more benign and effective way than caffeine energy drinks. The bottom line (see details below) is that after taking the mixture the first time I felt more calm and focused, with decreased mind noise and wandering (I think I'm being objective, but it is hard to rule out a placebo effect). After two days, I had to halve the dosage supplied to avoid several side effects noted in web accounts, brain fog, mild headaches, and body nervousness (hyperkinesia).  After the 10 day regime indicated by the instructions, I stopped the supplement for several days and did not note any obvious changes in ability to focus versus distractibility and mind wandering. (Which makes me wonder if the drug might have training my awareness so that it rendered itself unnecessary?) On resuming half dosage as before, I didn't notice the same dramatic effect as when first starting to take it, and the brain fog side effect briefly returned.  Got the same result on waiting a few more days and trying again. I suspect different people will react differently to the TruBrain supplement I was testing.   More details:

As background, I will mention that I get a steady stream of email from companies wanting me to promote or link to their products. I have a cut and paste standard reply that declines such invitations. One particularly persistent suitor has been an outfit called TruBrain . They sell a product meant to promote mental focus, and have a very slick website on which I was unable to find any links to basic science supporting their claims. After my query about this, they did send me an "evidence table" that lists some research references on the components of their brew (PDF here). I decided to relent on my usual refusal to deal with reviewing a commercial product, offered to try the stuff, and they sent a trial box.

The product came in a designer box almost up to Apple Product standards, with tidy little packets of pills to be consumed at breakfast and lunch, and most useful, a clear listing of the ingredients and amounts of the daily dosage. (I guess the cost of packaging and marketing is one reason the price of this supplement mix seems a bit steep to me.) Various combinations of the following ingredients and others are offered by vendors of Nootropics that you can quickly find on the web in a google search for nootropics or piracetam.

The ingredients:  

Piracetam 4g This is the heavy lifter in the mix, a cyclic derivative of the inhibitory neurotransmitter GABA (gamma amino butyric acid). It has extremely low toxicity, and several studies claim that it enhances attentional focus and decreases distractibility. The best guess is that it alters the function of acetylcholine synapses.  The majority of users report no side effects, but reported side effects do include nervousness, weight gain, increased body movements (hyperkinesia), headaches, irritability, depression, brain fog, G.I. distress.

Omega-3 Fatty Acids as DHA 200 mg
Acetyl-L Carnitine 200 mg (the energy producing ingredient in my second experiment noted above)
L-Tyrosine (an amino acid) 450 mg
CDP-Choline 345 mg
L-Theanine 300 mg (a compound in green tea).
Magnesium (as chelated lysinate/arginate) 80mg.

Diary:
Days 1 and 2 - notable calm and focus, decreased mind noise and mind wandering
Day 3 appearance of mild nervousness/agitation, hyperkinesia, brain fog or woozy feeling (not vestibular, balance and movement OK)
Day 4 side effects diminished, but still an unacceptable level of mind fog and body nervousness, alongside calm and focus, low mind noise and wandering.
Day 5 Dosage cut by half (3 instead of 5 pills taken with breakfast, 1 instead of 3 pills taken with lunch). Brain fog only remaining side effect, noticeable but marginally acceptable given enhancement of focus and inhibition of distractibility.
Day 10 By day 10, still taking half the recommended dosage, enhanced focus and reduced distractibility were continuing,  side effects were minimal.

I decided to see the effect of discontinuing the supplement. Would the enhanced focus and decreased distractibility wane over the next few days, returning me to my more normal multitasking distractible state? Or, alternatively, might I have undergone some brain training or conditioning, learning what greater calm, focus, decreased mind noise and wandering feels like, so that it continued after the supplement was withdrawn?  (There is speculation and debate over whether A.D.H.D. drugs might be neuroprotective, rewiring and normalizing a child's neural connections over time, so that more focused behavior continues after medication is withdrawn.)

Alas, I felt very little effect of discontinuing the supplement, focus versus distractibility and mind wandering seemed just fine.   After three days I resumed half the recommended, didn't note any change in focus, but the mind fog side effect returned for about half a day.  I waited another week and tried again...same result.  I may continue to putter with the product, but at this point am a bit underwhelmed.

How musical sound becomes rewarding - predictions and the brain

I would like to point out this review in Trends in Cognitive Sciences. Seeing more than the summary below does require a subscription or other access.

•Dopamine release in mesolimbic reward circuits leads to reinforcement tied to predictions and outcomes. 

•Musical pleasure involves complex interactions between dopamine systems and cortical areas. 

•Individual variability in superior temporal cortex may explain varied musical preferences. 

•Cognitive, auditory, affective, and reward circuits interact to make music pleasurable. 

Music has always played a central role in human culture. The question of how musical sounds can have such profound emotional and rewarding effects has been a topic of interest throughout generations. At a fundamental level, listening to music involves tracking a series of sound events over time. Because humans are experts in pattern recognition, temporal predictions are constantly generated, creating a sense of anticipation. We summarize how complex cognitive abilities and cortical processes integrate with fundamental subcortical reward and motivation systems in the brain to give rise to musical pleasure. This work builds on previous theoretical models that emphasize the role of prediction in music appreciation by integrating these ideas with recent neuroscientific evidence.

I will pass on some clips that summarize brain areas involved in auditory and music perception:

The superior temporal cortex (STC), which houses both primary and secondary auditory areas, is involved in a wide range of auditory processing relevant to music, including processing pitch and extraction of pitch and tonal relationships. It is also thought to store templates of sound events that we have accumulated over the years. Electrical stimulation of the STC elicits musical hallucinations, and increased activity in this region is associated with imagery and familiarity of music, suggesting that it stores previously heard auditory information. Acquired auditory information stored in this region may provide the basis for expectancy generation during music listening.

To appreciate music is to recognize patterns by sequencing structural information, recognizing the underlying structure, and forming predictions. These processes are continuously updated, refined, and revised with incoming information. These operations typically involve the frontal cortices of the brain, particularly the Inferior frontal gyrus (IFG)...The IFG and STG are often co-activated, and may possibly work together to process various aspects of music. Furthermore, there is evidence that white matter connectivity in this pathway is associated with the ability to learn new syntactic structures in the auditory domain. Finally, disruption of STG–IFG pathways has been observed in people with congenital amusia who show music perception deficits.

...dopaminergic coding of cues predicting upcoming rewards, and dopaminergic signaling of positive prediction errors, are essential to the high incentive reward value of musical experience. [One study] combined [¹¹C]-raclopride positron emission tomography and fMRI to show dopamine release in two regions of the striatum (caudate and nucleus accumbens, NAcc) while participants listened to self-selected highly pleasurable music. This study also found differential hemodynamic responses in these regions during anticipation versus experience of peak pleasure moments in the music

Changing bodies changes minds.

A fascinating review by Maister et al. notes studies showing that inducing illusory ownership over the body of a different race, age, or gender person changes implicit social biases, indicating that multisensory experience of our bodies underpins higher-level social attitudes.  I pass on their summaries:

•Multisensory correlations can induce illusory ownership of another person's body.
•Ownership can thus be induced over a body of a different race, age, or gender.
•Incorporating a body belonging to a social outgroup changes implicit social biases.
•The multisensory experience of the body underpins higher-level social attitudes. 

Research on stereotypes demonstrates how existing prejudice affects the way we process outgroups. Recent studies have considered whether it is possible to change our implicit social bias by experimentally changing the relationship between the self and outgroups. In a number of experimental studies, participants have been exposed to bodily illusions that induced ownership over a body different to their own with respect to gender, age, or race. Ownership of an outgroup body has been found to be associated with a significant reduction in implicit biases against that outgroup. We propose that these changes occur via a process of self association that first takes place in the physical, bodily domain as an increase in perceived physical similarity between self and outgroup member. This self association then extends to the conceptual domain, leading to a generalization of positive self-like associations to the outgroup.

And here is their description of manipulations of body ownership:

Rubber Hand Illusion (RHI)

Watching a rubber hand being stroked synchronously with one's own unseen hand causes the rubber hand to be attributed to one's own body, to ‘feel like it's my hand’. This synchronous stimulation not only elicits a subjective experience of ownership over the hand, but also causes the perceived location of one's own hand to drift towards the rubber hand  and a stress-evoked skin conductance response to be elicited when the rubber hand is threatened. The illusion of ownership over the rubber hand does not occur when the rubber hand is stroked asynchronously with respect to the subject's own hand, and thus experiments investigating body ownership commonly use asynchronous stimulation as a control condition. An illusion of the same intensity can be also developed over a virtual hand by either synchronous visuotactile or visuomotor correlations. This illusion persists through radical transformations such as extensive elongation of the arm  or change in the virtual hand position with respect to the real one.

Enfacement Illusion

The enfacement illusion is a facial analogue of the rubber hand illusion. Participants watch a video showing the face of an unfamiliar other being stroked with a cotton bud on the cheek, while the participant receives identical stroking on their own, congruent cheek in synchrony with the touch they see. As in the RHI, synchronous, but not asynchronous, visuotactile stimulation elicits illusory feelings of ownership over the other's face. Enfacement also influences social cognition and produces a measurable bias in self-face recognition, whereby participants perceive the other's face as looking more like their own.

Full Body Illusions

Illusory ownership over a physical manikin body that substituted the participant's real body was demonstrated in. Live video, from cameras attached to the manikin, was streamed to head-mounted displays on the participants, so that when looking down they would see the manikin body visually substituting their own. Synchronous tapping on the manikin body and the real body led to illusory body ownership, in a similar way to the more traditional rubber hand and enfacement illusions. More advanced systems have now been developed, using Immersive Virtual Reality (IVR). Participants wear a head-tracked stereo head-mounted display which provides computer generated images immersing the participant in a virtual world. The participant's own body is substituted by a virtual body, viewed from a first-person perspective, with a motion capture system so that their virtual body moves with their real body movements. This set up results in sensorimotor correlations (visual, proprioceptive, tactile, and motor) that elicit illusions of ownership and agency over the virtual body.

MindBlog's other lives - a piano concert

I thought I would share with MindBlog readers this video made at my piano recital last Sunday in Fort Lauderdale by Rex Coston, an amazing 90+ year old guy, who is totally on top of the web photo and video scene.
 

A further video clip Rex did is here.

Watching large scale brain network interactions in cognitive control.

We frequently face situations in which we must override our ongoing behavior to react to a situational demand, a process that is impaired in many patients with traumatic brain injury (TBI). Two large scale networks important in this cognitive control are the salience network and the default mode network (DMN). From the review by Kumfor et al:

The salience network is recruited in response to attention-grabbing changes in the environment, and it is anchored by the dorsal anterior cingulate cortex and orbital frontoinsular cortices, with robust connections with subcortical and limbic structures. Conversely, the DMN is activated when current situational demands are insufficient to capture our attention (e.g., during monotonous tasks); it encompasses a distributed set of regions including the medial and lateral temporal cortices and inferior lateral parietal cortices, centered on midline “hubs,” including the dorsomedial prefrontal and posterior cingulate cortices.

Jilka et al. have monitored the activity of these networks in control and TBI subjects while they carried out two cognitive control tasks: a stop signal task in which participants were shown either left or right arrows and asked to press the corresponding left or right keys - except when a red dot was shown; and a motor switching task in which participants learned to respond to blue targets with their left hand and red targets with their right hand - except when they were instructed to switch their response. Successful performance on both tasks correlated with increased functional connectivity between the right anterior insula node of the salience network and the DMN. Deficits in inhibition seen in TBI patients correlated with decreased functional connectivity. Here is their abstract:

Interactions between the Salience Network (SN) and the Default Mode Network (DMN) are thought to be important for cognitive control. However, evidence for a causal relationship between the networks is limited. Previously, we have reported that traumatic damage to white matter tracts within the SN predicts abnormal DMN function. Here we investigate the effect of this damage on network interactions that accompany changing motor control. We initially used fMRI of the Stop Signal Task to study response inhibition in humans. In healthy subjects, functional connectivity (FC) between the right anterior insula (rAI), a key node of the SN, and the DMN transiently increased during stopping. This change in FC was not seen in a group of traumatic brain injury (TBI) patients with impaired cognitive control. Furthermore, the amount of SN tract damage negatively correlated with FC between the networks. We confirmed these findings in a second group of TBI patients. Here, switching rather than inhibiting a motor response: (1) was accompanied by a similar increase in network FC in healthy controls; (2) was not seen in TBI patients; and (3) tract damage after TBI again correlated with FC breakdown. This shows that coupling between the rAI and DMN increases with cognitive control and that damage within the SN impairs this dynamic network interaction. This work provides compelling evidence for a model of cognitive control where the SN is involved in the attentional capture of salient external stimuli and signals the DMN to reduce its activity when attention is externally focused.

Causal emergence in our brains

I recently came across an important paper that I didn't spot when it first appeared in 2013. Tononi and collaborators question the common assumption that knowing everything about the micro level of neurons and their interactions can completely specify the behavior of macro levels of systems of neurons. They use simple simulated systems, including neural-like ones, to show quantitatively that the macro level can causally supersede the micro level, i.e., causal emergence can occur. In practical terms this means, for example, that interactions between nodes in the salience (attentional) or default brain networks that generate our behaviors might be better understood at their level than by knowing everything about the zillions of synapses that compose them. (This perspective is an antidote to the purists who maintain that macro level studies are putting the cart before the horse...not getting us there if we haven't painstakingly worked out the steps of what goes on between ion channels, nerve cells, simple systems of nerve cells, and increasingly higher levels of integration.) My primitive mathematical abilities preclude me from really understanding their computations except in the most general way, I want to pass on their abstract, which is a dense but clear read:

Causal interactions within complex systems can be analyzed at multiple spatial and temporal scales. For example, the brain can be analyzed at the level of neurons, neuronal groups, and areas, over tens, hundreds, or thousands of milliseconds. It is widely assumed that, once a micro level is fixed, macro levels are fixed too, a relation called supervenience. It is also assumed that, although macro descriptions may be convenient, only the micro level is causally complete, because it includes every detail, thus leaving no room for causation at the macro level. However, this assumption can only be evaluated under a proper measure of causation. Here, we use a measure [effective information (EI)] that depends on both the effectiveness of a system’s mechanisms and the size of its state space: EI is higher the more the mechanisms constrain the system’s possible past and future states. By measuring EI at micro and macro levels in simple systems whose micro mechanisms are fixed, we show that for certain causal architectures EI can peak at a macro level in space and/or time. This happens when coarse-grained macro mechanisms are more effective (more deterministic and/or less degenerate) than the underlying micro mechanisms, to an extent that overcomes the smaller state space. Thus, although the macro level supervenes upon the micro, it can supersede it causally, leading to genuine causal emergence—the gain in EI when moving from a micro to a macro level of analysis.

Expensive drugs work better than cheap ones.

Bakalar points to work published in the journal Neurology that found that when Parkinson's disease patients were told they were testing two new drugs, one costing $100 and the other $1500 per dose (both in fact were plain saline solutions), they reported the more expensive drug had almost as much effect as levodopa, the most effective known medication for Parkinson's. Perhaps their hightened expectations of the expensive drug caused them to make more dopamine. (Dopamine levels normally rise in anticipation of pleasure or relief.) The study provides evidence that perception of cost is capable of influencing motor function and brain activation in Parkinson disease.

Computers judge personality more accurately than humans.

This is a bit scary, from Youyou et al.:

Judging others’ personalities is an essential skill in successful social living, as personality is a key driver behind people’s interactions, behaviors, and emotions. Although accurate personality judgments stem from social-cognitive skills, developments in machine learning show that computer models can also make valid judgments. This study compares the accuracy of human and computer-based personality judgments, using a sample of 86,220 volunteers who completed a 100-item personality questionnaire. We show that (i) computer predictions based on a generic digital footprint (Facebook Likes) are more accurate (r = 0.56) than those made by the participants’ Facebook friends using a personality questionnaire (r = 0.49); (ii) computer models show higher interjudge agreement; and (iii) computer personality judgments have higher external validity when predicting life outcomes such as substance use, political attitudes, and physical health; for some outcomes, they even outperform the self-rated personality scores. Computers outpacing humans in personality judgment presents significant opportunities and challenges in the areas of psychological assessment, marketing, and privacy.

Doubting global warming?

My colleague John Young, who is a member of the Univ. of Wisconsin Chaos and Complexity Seminar group I join when I am in Madison, circulated this video to the group. One wishes the current contenders for the Republican presidential candidate nomination, who are either in denial or indifferent to the climate change issue, would have a look. They would probably want to de-fund the climate.gov team that put the video together.
 

Decades ago, the majority of the Arctic's winter ice pack was made up of thick, perennial ice. Today, very old ice is extremely rare. This animation tracks the relative amount of ice of different ages from 1987 through early November 2014. Video produced by the Climate.gov team, based on data provided by Mark Tschudi.

From the more extended description:

This animation tracks the relative amount of ice of different ages from 1987 through early November 2014. The first age class on the scale (1, darkest blue) means "first-year ice,” which formed in the most recent winter. (In other words, it’s in its first year of growth.) The oldest ice (>9, white) is ice that is more than nine years old. Dark gray areas indicate open water or coastal regions where the spatial resolution of the data is coarser than the land map.

As the animation shows, Arctic sea ice doesn't hold still; it moves continually. East of Greenland, the Fram Strait is an exit ramp for ice out of the Arctic Ocean. Ice loss through the Fram Strait used to be offset by ice growth in the Beaufort Gyre, northeast of Alaska. There, perennial ice could persist for years, drifting around and around the basin’s large, looping current.

Around the start of the 21st century, however, the Beaufort Gyre became less friendly to perennial ice. Warmer waters made it less likely that ice would survive its passage through the southernmost part of the gyre. Starting around 2008, the very oldest ice shrank to a narrow band along the Canadian Arctic Archipelago.

A landmark for our human brains.

The search for specifically human cortical landmarks has been frustrating. Reported asymmetries in the planum temporale and the inferior frontal region are not as robust as initially thought and also are observed, less marked, in other primates. Leroy et al. have now identified an asymmetry of the superior temporal sulcus (STS), at the core of our human communication and social cognition systems, that represents a species-specific perisylvian anatomical marker that is barely visible in chimpanzees. They suggest that focusing on gene expression relevant to this regions might shed light on the evolution of our crucial cognitive abilities. Here is their abstract and a figure from the paper:

Identifying potentially unique features of the human cerebral cortex is a first step to understanding how evolution has shaped the brain in our species. By analyzing MR images obtained from 177 humans and 73 chimpanzees, we observed a human-specific asymmetry in the superior temporal sulcus at the heart of the communication regions and which we have named the “superior temporal asymmetrical pit” (STAP). This 45-mm-long segment ventral to Heschl’s gyrus is deeper in the right hemisphere than in the left in 95% of typical human subjects, from infanthood till adulthood, and is present, irrespective of handedness, language lateralization, and sex although it is greater in males than in females. The STAP also is seen in several groups of atypical subjects including persons with situs inversus, autistic spectrum disorder, Turner syndrome, and corpus callosum agenesis. It is explained in part by the larger number of sulcal interruptions in the left than in the right hemisphere. Its early presence in the infants of this study as well as in fetuses and premature infants suggests a strong genetic influence. Because this asymmetry is barely visible in chimpanzees, we recommend the STAP region during midgestation as an important phenotype to investigate asymmetrical variations of gene expression among the primate lineage. This genetic target may provide important insights regarding the evolution of the crucial cognitive abilities sustained by this sulcus in our species, namely communication and social cognition.

Legend - Location of the STAP (yellow) relative to Heschl’s gyrus (blue) and the ventral tip of the central sulcus (green) on both left and right inner cortical surfaces of an individual adult brain. The STAP center is shown by a cross. The black dot with a white contour line shows the planum temporale landmark.  (Click on figure to enlarge.)

Another study on exercise keeping us young - and other fitness trends

Because there are currently no generally agreed on markers of human ageing, Pollock et al. (see review by Reynolds) decided to examine the relationship between age and physiological function by removing inactivity as a factor. They recruited and performed physiological and psychological profiling on a cohort of 55-79 year old very active cyclists. As a group, even the oldest cyclists had younger people’s levels of balance, reflexes, metabolic health and memory ability. Despite studying a large number and diverse range of indices, the authors were not able to identify a physiological marker that could be used to reliably predict the age of a given individual.

Other items from my queue of potential posts:

Reynolds does a review of recent fitness trends such as the super short workout with high intensity bursts, and Brody adds further information on high intensity interval training as an antidote to several chronic ilnesses.

Communicating by having our brains in synchrony.

Stolk et al. have done an interesting experiment by doing MRI scans of people communicating only through a visual display who were working together to complete a task. They found that pair-specific interpersonal synchronization of right temporal lobe activity was driven by communicative episodes in which communicators needed to mutually adjust their conceptualizations of a signal’s use. Thus, it appears that establishing mutual understanding relies on spatially and temporally coherent brain activity between the two people communicating.

Significance

Building on recent electrophysiological evidence showing that novel communicative behavior relies on computations that operate over temporal scales independent from transient sensorimotor behavior, here we report that those computations occur simultaneously in pairs with a shared communicative history, but not in pairs without a shared history. This pair-specific interpersonal synchronization was driven by communicative episodes in which communicators needed to mutually adjust their conceptualizations of a signal’s use. That interpersonal cerebral synchronization was absent when communicators used stereotyped signals. These findings indicate that establishing mutual understanding is implemented through simultaneous in-phase coordination of cerebral activity across communicators, consistent with the notion that pair members temporally synchronize their conceptualizations of a signal’s use.

Abstract

How can we understand each other during communicative interactions? An influential suggestion holds that communicators are primed by each other’s behaviors, with associative mechanisms automatically coordinating the production of communicative signals and the comprehension of their meanings. An alternative suggestion posits that mutual understanding requires shared conceptualizations of a signal’s use, i.e., “conceptual pacts” that are abstracted away from specific experiences. Both accounts predict coherent neural dynamics across communicators, aligned either to the occurrence of a signal or to the dynamics of conceptual pacts. Using coherence spectral-density analysis of cerebral activity simultaneously measured in pairs of communicators, this study shows that establishing mutual understanding of novel signals synchronizes cerebral dynamics across communicators’ right temporal lobes. This interpersonal cerebral coherence occurred only within pairs with a shared communicative history, and at temporal scales independent from signals’ occurrences. These findings favor the notion that meaning emerges from shared conceptualizations of a signal’s use.

Low social status enhances prosocial orientation.

Interesting observations from Guinote et al. :

Humans are a cooperative species, capable of altruism and the creation of shared norms that ensure fairness in society. However, individuals with different educational, cultural, economic, or ethnic backgrounds differ in their levels of social investment and endorsement of egalitarian values. We present four experiments showing that subtle cues to social status (i.e., prestige and reputation in the eyes of others) modulate prosocial orientation. The experiments found that individuals who experienced low status showed more communal and prosocial behavior, and endorsed more egalitarian life goals and values compared with those who experienced high status. Behavioral differences across high- and low-status positions appeared early in human ontogeny (4–5 y of age).

This is yet another study using undergraduate college students as subjects. The first experiment manipulated perceived status by telling students their department had high versus low national rankings. After this simple intervention, lower status students showed more helpful behavior when an experimenter pretended to drop a pack of pens on the floor. A second experiment gave a group bogus feedback about their group standing compared with another group. Individuals in low status groups showed more communal and prosocial signaling during self-presentations and interactions than those in high status groups. The third experiment had a status manipulation similar to the first, and the life goals of low versus high status subjects were probed, the finding being that lower lower status participants indicated more benevolent self-transcendent life goals while higher-status participants endorsed more power values. The fourth study was done with a group of 28 children of mean age 4.7 years. After manipulations of their dominance hierarchy, lower status children were more generous and helpful than higher status peers.

Parallel brain systems regulate our pain.

Our subjective sensory experiences are regulated by defined brain areas subh visual cortex, auditory cortex,somatosensory cortex, etc., but there doesn't appear to be a "pain cortex" that directly codes our subjective perception of pain. Mano and Seymour, in a review of Woo et al., note the emerging concept that pain might emerge from the coordinated activity of an integrated brain network. Woo et al. provide evidence that distinct brain networks support the subjective changes in pain that result from nociceptive input and self-directed cognitive modulation. Their abstract, followed by a summary graphic from Mano and Seymour:

Cognitive self-regulation can strongly modulate pain and emotion. However, it is unclear whether self-regulation primarily influences primary nociceptive and affective processes or evaluative ones. In this study, participants engaged in self-regulation to increase or decrease pain while experiencing multiple levels of painful heat during functional magnetic resonance imaging (fMRI) imaging. Both heat intensity and self-regulation strongly influenced reported pain, but they did so via two distinct brain pathways. The effects of stimulus intensity were mediated by the neurologic pain signature (NPS), an a priori distributed brain network shown to predict physical pain with over 90% sensitivity and specificity across four studies. Self-regulation did not influence NPS responses; instead, its effects were mediated through functional connections between the nucleus accumbens and ventromedial prefrontal cortex. This pathway was unresponsive to noxious input, and has been broadly implicated in valuation, emotional appraisal, and functional outcomes in pain and other types of affective processes. These findings provide evidence that pain reports are associated with two dissociable functional systems: nociceptive/affective aspects mediated by the NPS, and evaluative/functional aspects mediated by a fronto-striatal system.

Distinct component to the subjective perception of pain. Core nociceptive nodes comprise a multivariate pattern (the neurological pain signature [NPS]), and fronto-striatal brain regions comprise an evaluative pathway sensitive to self-directed cognitive modulation.

Power and your voice.

Margaret Thatcher did it, and so can you. She went through voice training that permitted her to exude a more authoritative powerful persona. Her voice became higher in pitch and loudness variability but lower in pitch variability, like playing a piano with a smaller number of notes, but varying their volume more. Ko et al. report a similar transformation in the usual cadre of college undergraduates recruited for an experiment. Here is a description of the experiments provided by an APS summary:

In the first experiment, they recorded 161 college students reading a passage aloud; this first recording captured baseline acoustics. The participants were then randomly assigned them to play a specific role in an ensuing negotiation exercise.

Students assigned to a “high” rank were told to go into the negotiation imagining that they either had a strong alternative offer, valuable inside information, or high status in the workplace, or they were asked to recall an experience in which they had power before the negotiation started. Low-rank students, on the other hand, were told to imagine they had either a weak offer, no inside information, or low workplace status, or they were asked to recall an experience in which they lacked power.

The students then read a second passage aloud, as if they were leading off negotiations with their imaginary adversary, and their voices were recorded. Everyone read the same opening, allowing the researchers to examine acoustics while holding the speech content constant across all participants.

Comparing the first and second recordings, the researchers found that the voices of students assigned to high-power roles tended to go up in pitch, become more monotone (less variable in pitch), and become more variable in loudness than the voices of students assigned low-power roles.

And the students’ vocal cues didn’t go unnoticed. A second experiment with a separate group of college students revealed that listeners, who had no knowledge of the first experiment, were able to pick up on these power-related vocal cues to determine who did and did not have power: Listeners ranked speakers who had been assigned to the high-rank group as more likely to engage in high-power behaviors, and they were able to categorize whether a speaker had high or low rank with considerable accuracy.

In line with the vocal changes observed in the first experiments, listeners tended to associate higher pitch and voices that varied in loudness with high-power behaviors. They also associated louder voices with higher power.

Musical training accelerates cortical thickness maturation.

Hudziak et al. have examined a database of MRI scans of 232 youths ranging from 6 to 18 years of age, obtained over a period of years. Their analysis revealed that music training was associated with an increased rate of cortical thickness maturation.  Clips from their discussion and a figure:

Music training was associated with the rate of cortical thickness maturation in a number of brain areas distributed throughout the right premotor and primary cortices, the left primary and supplementary motor cortices, bilateral parietal cortices, bilateral orbitofrontal cortices, as well as bilateral parahippocampal gyri. Our finding that music training was associated with cortical thickness development in the premotor and primary motor cortices is not surprising, given that both regions contribute to the control and execution of movement.

Music training was also found to influence cortical thickness maturation within aspects of the DLPFC. Myriad imaging and neuropsychological studies have implicated the DLPFC in aspects of executive functioning, including working memory, attentional control, as well as organization and planning for the future. Interestingly, developmental structural neuroimaging studies have shown that participants with quantitatively higher scores on attention problems exhibit delayed cortical thickness maturation in portions of the DLPFC as well as other cortical regions.

Brain areas where local cortical thickness is associated with the “Age × Years of Playing” interaction (N = 232; 334 time points)

Judging and adapting to norm violations engage different brain regions.

Gu et al. find that our insula is critical for learning to adapt when reality deviates from norm expectations, and the ventromedial prefrontal cortex is important for valuation of fairness during social exchange.

Social norms and their enforcement are fundamental to human societies. The ability to detect deviations from norms and to adapt to norms in a changing environment is therefore important to individuals' normal social functioning. Previous neuroimaging studies have highlighted the involvement of the insular and ventromedial prefrontal (vmPFC) cortices in representing norms. However, the necessity and dissociability of their involvement remain unclear. Using model-based computational modeling and neuropsychological lesion approaches, we examined the contributions of the insula and vmPFC to norm adaptation in seven human patients with focal insula lesions and six patients with focal vmPFC lesions, in comparison with forty neurologically intact controls and six brain-damaged controls. There were three computational signals of interest as participants played a fairness game (ultimatum game): sensitivity to the fairness of offers, sensitivity to deviations from expected norms, and the speed at which people adapt to norms. Significant group differences were assessed using bootstrapping methods. Patients with insula lesions displayed abnormally low adaptation speed to norms, yet detected norm violations with greater sensitivity than controls. Patients with vmPFC lesions did not have such abnormalities, but displayed reduced sensitivity to fairness and were more likely to accept the most unfair offers. These findings provide compelling computational and lesion evidence supporting the necessary, yet dissociable roles of the insula and vmPFC in norm adaptation in humans: the insula is critical for learning to adapt when reality deviates from norm expectations, and that the vmPFC is important for valuation of fairness during social exchange.

Subjective status shapes political preferences.

Brown-Iannuzzi et al. suggest that people's subjective perception of their socioeconomic status (SES) has a large influence on whether they support wealth redistribution as a remedy for increasing economic inequality in America. This is distinct from attitudes based on economic ideologies and economic self-interest. Here is their abstract, followed by their description of their studies:

Economic inequality in America is at historically high levels. Although most Americans indicate that they would prefer greater equality, redistributive policies aimed at reducing inequality are frequently unpopular. Traditional accounts posit that attitudes toward redistribution are driven by economic self-interest or ideological principles. From a social psychological perspective, however, we expected that subjective comparisons with other people may be a more relevant basis for self-interest than is material wealth. We hypothesized that participants would support redistribution more when they felt low than when they felt high in subjective status, even when actual resources and self-interest were held constant. Moreover, we predicted that people would legitimize these shifts in policy attitudes by appealing selectively to ideological principles concerning fairness. In four studies, we found correlational (Study 1) and experimental (Studies 2–4) evidence that subjective status motivates shifts in support for redistributive policies along with the ideological principles that justify them.

In Study 1, we measured subjective and objective SES and predicted that higher subjective SES would be associated with greater opposition to redistributive policies, independently of objective SES. In Study 2, we manipulated subjective SES, hypothesizing that participants induced to feel high status would be less supportive of redistribution and would endorse a more conservative ideology to justify that position than would participants induced to feel low status. In Study 3, we gained greater experimental control by creating an economic game in which players earned money and a portion of the profits of high earners were redistributed to low earners. We manipulated how well participants performed relative to other players, and we predicted that players who performed better would support less redistribution and would justify their preferences on the basis of ideological principles. In Study 4, we sought to replicate this finding and investigated whether the manipulation of subjective status led high-status participants to perceive other participants who disagreed with them as biased by self-interest. Together, these studies investigated whether subjective status may lead to political division.

[The results provide evidence] that perceptions of relative status can cause changes in political preferences. In Study 1, feeling higher in relative status was associated with lower support for redistribution. In Study 2, feeling higher in status caused reduced support for redistribution. In Study 3, we manipulated relative status in the context of an economic game and obtained similar results. Although participants could not profit from their recommendations, they recommended rule changes to reduce redistribution when they believed they had outperformed most other players. These changes were accompanied by shifts in construals of what counts as fair. Study 4 replicated these effects and showed that participants’ status affected their perceptions of bias in another player. High-status participants thought a player who recommended increased redistribution was more biased by self-interest than a player who recommended cutting redistribution. Together, these results suggest that subjective feelings of status can drive opinions toward redistribution, along with ideological views that justify those positions. An implication of the present work is that growing subjective perceptions of class differences may drive increased political polarization.

We can see in the infrared!

The major part of my professional life was spent doing research on how the rod cells in our retinas change light into a nerve signal. (I just got a request from ResearchGate, a site on which scientists list their work, suggesting that I upload another of my old vision articles, in this case one that appeared in Nature - in 1965 - 50 years ago! - titled "Reaction of the Rhodopsin Chromophore with Sodium Borohydride".) Even though for the past 20 years or so I have focused on the topics covered by MindBlog I occasionally see a vision article that takes me back to 'the old days'. A colleague from those days (Krzysztof Palczewski) and collaborators have recently done a nice piece of work demonstrating that we can actually expand our vision beyond the normal "visible" range of 400 (blue) to 720 (red) nanometer (nm) wavelengths into the higher frequency (lower energy) infrared regions emitted by infrared lasers. It turns out that the Rhodopsin Chromophore of my article above, retinal, which normally has its shape changed (isomerized) by absorbing one photon of visible light, can be activated by a two-photon chromophore isomerization, especially at wavelengths above 900 nm. From their significance and abstract statements:

This study resolves a long-standing question about the ability of humans to perceive near infrared radiation (IR) and identifies a mechanism driving human IR vision. A few previous reports and our expanded psychophysical studies here reveal that humans can detect IR at wavelengths longer than 1,000 nm and perceive it as visible light, a finding that has not received a satisfactory physical explanation. We show that IR light activates photoreceptors through a nonlinear optical process.

Vision relies on photoactivation of visual pigments in rod and cone photoreceptor cells of the retina. The human eye structure and the absorption spectra of pigments limit our visual perception of light. Our visual perception is most responsive to stimulating light in the 400- to 720-nm (visible) range. First, we demonstrate by psychophysical experiments that humans can perceive infrared laser emission as visible light. Moreover, we show that mammalian photoreceptors can be directly activated by near infrared light with a sensitivity that paradoxically increases at wavelengths above 900 nm, and display quadratic dependence on laser power, indicating a nonlinear optical process. Biochemical experiments with rhodopsin, cone visual pigments, and a chromophore model compound 11-cis-retinyl-propylamine Schiff base demonstrate the direct isomerization of visual chromophore by a two-photon chromophore isomerization. Indeed, quantum mechanics modeling indicates the feasibility of this mechanism. Together, these findings clearly show that human visual perception of near infrared light occurs by two-photon isomerization of visual pigments.

Steven Pinker's "Sense of Style"

I've just read through Steven Pinker's new book "The Sense of Style: The Thinking Person's Guide to Writing in the 21st Century." It is a lucid exposition, and I wish that I were disciplined enough to heed its exhortations on substance and clarity. I can't resist passing on the following clips from Chapter 2, the second paragraph in particular grabs me.:

Writing is an unnatural act. As Charles Darwin observed, “Man has an instinctive tendency to speak, as we see in the babble of our young children, whereas no child has an instinctive tendency to bake, brew, or write.” The spoken word is older than our species, and the instinct for language allows children to engage in articulate conversation years before they enter a schoolhouse. But the written word is a recent invention that has left no trace in our genome and must be laboriously acquired throughout childhood and beyond.

At the time that we write, the reader exists only in our imaginations. Writing is above all an act of pretense. We have to visualize ourselves in some kind of conversation, or correspondence, or oration, or soliloquy, and put words into the mouth of the little avatar who represents us in this simulated world. The key to good style, far more than obeying any list of commandments , is to have a clear conception of the make-believe world in which you’re pretending to communicate.

Which simulation should a writer immerse himself in when composing a piece for a more generic readership, such as an essay, an article, a review, an editorial, a newsletter, or a blog post? The literary scholars Francis-Noël Thomas and Mark Turner have singled out one model of prose as an aspiration for such writers today. They call it classic style, and explain it in a wonderful little book called Clear and Simple as the Truth.

The guiding metaphor of classic style is seeing the world. The writer can see something that the reader has not yet noticed, and he orients the reader’s gaze so that she can see it for herself. The purpose of writing is presentation, and its motive is disinterested truth. It succeeds when it aligns language with the truth, the proof of success being clarity and simplicity. The truth can be known, and is not the same as the language that reveals it; prose is a window onto the world. The writer knows the truth before putting it into words; he is not using the occasion of writing to sort out what he thinks. Nor does the writer of classic prose have to argue for the truth; he just needs to present it. That is because the reader is competent and can recognize the truth when she sees it, as long as she is given an unobstructed view. The writer and the reader are equals, and the process of directing the reader’s gaze takes the form of a conversation.

The signature of consciousness in resting-state brain activity.

I've done a number of posts on attentional or salience versus default mode long-range connectivity networks in our brains (for a review see my lecture.) They correspond roughly to supporting outward task oriented processes versus inward processes such as daydreaming or imagining. Activity in these networks is thought to be a marker of consciousness, but this idea conflicts with observations that long-range functional connectivities persist even after loss of consciousness caused by anesthesia, or in vegetative state patients. This post is to point to recent work by Dehaene and collaborators showing clear difference in the behavior of long-range networks in awake and anesthetized monkeys. Their abstract and statement of significance, followed by a movie showing whole brain connectivity patterns at different time points in the awake monkey.

Significance

What are the origins of resting-state functional connectivity patterns? One dominating view is that they index ongoing cognitive processes. However, this conclusion is in conflict with studies showing that long-range functional connectivity persists after loss of consciousness, possibly reflecting structural connectivity maps. In this work we respond to this question showing that in fact both sources have a clear and separable contribution to resting-state patterns. We show that under anesthesia, the dominating functional configurations have low information capacity and lack negative correlations. Importantly, they are rigid, tied to the anatomical map. Conversely, wakefulness is characterized by the dynamical exploration of a rich, flexible repertoire of functional configurations. These dynamical properties constitute a signature of consciousness.

Abstract

At rest, the brain is traversed by spontaneous functional connectivity patterns. Two hypotheses have been proposed for their origins: they may reflect a continuous stream of ongoing cognitive processes as well as random fluctuations shaped by a fixed anatomical connectivity matrix. Here we show that both sources contribute to the shaping of resting-state networks, yet with distinct contributions during consciousness and anesthesia. We measured dynamical functional connectivity with functional MRI during the resting state in awake and anesthetized monkeys. Under anesthesia, the more frequent functional connectivity patterns inherit the structure of anatomical connectivity, exhibit fewer small-world properties, and lack negative correlations. Conversely, wakefulness is characterized by the sequential exploration of a richer repertoire of functional configurations, often dissimilar to anatomical structure, and comprising positive and negative correlations among brain regions. These results reconcile theories of consciousness with observations of long-range correlation in the anesthetized brain and show that a rich functional dynamics might constitute a signature of consciousness, with potential clinical implications for the detection of awareness in anesthesia and brain-lesioned patients.

Dynamical connectivity matrix - red lines mark positive correlations, and blue lines mark negative correlations.

Body movements shape brain representation of musical rhythms.

Entraining our movement to music is a universal human behavior. The enhancement of social cohesion by group movements in synchrony with the rhythms of chants and songs could have had an adaptive value in human evolution. Chemin et al. have done the interesting experiment of recording EEG evoked potentials caused by study participants listening to an ambiguous rhythm, before and after a body-movement session designed to disambiguate the perception of this rhythm by favoring a specific meter (e.g., two beats per measure vs. three beats per measure). They found that the brain responses to the rhythm after body movement were significantly enhanced at frequencies related to the meter to which the participants had moved. Here is their abstract:

It is increasingly recognized that motor routines dynamically shape the processing of sensory inflow (e.g., when hand movements are used to feel a texture or identify an object). In the present research, we captured the shaping of auditory perception by movement in humans by taking advantage of a specific context: music. Participants listened to a repeated rhythmical sequence before and after moving their bodies to this rhythm in a specific meter. We found that the brain responses to the rhythm (as recorded with electroencephalography) after body movement were significantly enhanced at frequencies related to the meter to which the participants had moved. These results provide evidence that body movement can selectively shape the subsequent internal representation of auditory rhythms.

An Example of Publication Bias - Cognitive Advantage in Bilingualism

MindBlog has done several posts on experiments that reinforce what has become the conventional wisdom regarding bilingualism: that it enhances our executive control faculties. De Bruin et al., noting that they themselves had chosen to report positive results supporting this conclusion, but had not followed through on negative data (the file drawer effect), thought to do a systematic analysis of the publication fate of experiments with positive, mixed, or negative outcomes. They searched for conference abstracts on bilingualism and executive control in 169 conferences (31 different national and international meetings) organized between 1999 and 2012, and identified 128 abstracts (presented at 52 different conferences) that focused on bilingualism and executive control. Their result:

Sixty-eight percent of the studies that clearly found a bilingual advantage were published, compared with 50% of the studies that found mixed results supporting the bilingual-advantage theories, 39% of the studies that found mixed results partly challenging those theories, and 29% of the studies that found no differences between monolinguals and bilinguals or found a bilingual disadvantage. On the whole, 63% of the studies supporting the bilingual advantage were published, compared with only 36% of the studies that challenged it.

From the authors discussion:

This difference in publication percentage based on the outcomes of the study could be the result of a bias during several steps of the publication process: Authors, reviewers, and editors can decide to submit or accept only studies that showed positive results. In the first step of the publication process, the file-drawer problem could play an important role in the observed publication bias. Authors could decide not to publish studies with null or mixed results, or they could choose to submit their results only partially, for example, by leaving out tasks that did not show an effect of bilingualism. The article by Treccani et al. (2009)[Treccani is a co-author of the current paper] is an example of the file-drawer problem, as it excluded the experiments that did not show an effect of bilingualism.

On the next level, reviewers and editors might reject manuscripts reporting null, negative, or mixed results more often than manuscripts reporting positive effects. This rejection is often based on the argument that null effects are difficult to interpret, or the result of poor stimulus design... Mahoney (1977) asked journal reviewers to referee manuscripts reporting positive, negative, mixed, or null results with identical methodological procedures. Although the methodology was the same, reviewers scored the manuscripts reporting positive results as methodologically better than the manuscripts reporting negative or mixed results. For manuscripts with positive results, reviewers usually recommended acceptance with moderate revisions. For manuscripts with negative results, however, their usual recommendation was major revision or rejection. Manuscripts with mixed results were mostly rejected.

Watching brain oscillations drive perception.

Are the electrical oscillations observed in EEG recordings as we perceive images simply correlations, reflecting brain processes driving our visual experience, or are the oscillations themselves causal, driving the visual experience? Helfrich et al. address this basic question in a clever experiment in which they force brain oscillations of the left and right visual hemispheres into synchrony using transcranial alternating current stimulation. This causes human subjects to more often perceive an ambiguous figure in one of its perceptual instantiations, showing that the oscillations are driving the visual experience, not vice versa. Their summary:

Brain activity is profoundly rhythmic and exhibits seemingly random fluctuations across a very broad frequency range (less than 0.1 Hz to greater than 600 Hz). Recently, it has become evident that these brain rhythms are not just a generic sign of the brain-at-work, but actually reflect a highly flexible mechanism for information encoding and transfer. In particular, it has been suggested that oscillatory synchronization between different areas of the cortex underlies the establishment of task-relevant networks. Here, we investigated whether gamma-band synchronization (~40 Hz) is causally involved in the integration between the two brain hemispheres of alternating visual tokens into a coherent motion percept. We utilized transcranial alternating current stimulation (tACS), a novel non-invasive brain stimulation technique, which allows frequency-specific entrainment of cortical areas. In a combined tACS-electroencephalography study, we selectively up- and down-regulated interhemispheric coherence, resulting in a directed bias in apparent motion perception: Increased interhemispheric connectivity sustained the horizontal motion percept, while decreased connectivity reinforced the vertical percept. Thus, our data suggest that the level of interhemispheric gamma-band coherence directly influenced the instantaneous motion percept. From these results, we conclude that synchronized neuronal activity is essential for conscious perception and cognition.

Perceived control promotes persistence and influences brain response to setbacks

From Bhanji et al:

Highlights

•We report two distinct neural mechanisms for persistence through adversity 

•Perceiving control over setbacks increases persistence 

•Striatum activity relates to persisting after setbacks by correcting mistakes 

•Ventromedial prefrontal activity mediates effects of negative affect on persistence

Summary

How do people cope with setbacks and persist with their goals? We examine how perceiving control over setbacks alters neural processing in ways that increase persistence through adversity. For example, a student might retake a class if initial failure was due to controllable factors (e.g., studying) but give up if failure was uncontrollable (e.g., unfair exam questions). Participants persisted more when they perceived control over setbacks, and when they experienced increased negative affect to setbacks. Consistent with previous observations involving negative outcomes, ventral striatum and ventromedial prefrontal (VMPFC) activity was decreased in response to setbacks. Critically, these structures represented distinct neural mechanisms for persistence through adversity. Ventral striatum signal change to controllable setbacks correlated with greater persistence, whereas VMPFC signal change to uncontrollable setbacks mediated the relationship between increased negative affect and persistence. Taken together, the findings highlight how people process setbacks and adapt their behavior for future goal pursuit.

From Whalen and Kelly's review :

The vmPFC is necessary for regulating our emotional responses...in the present study, the negative affect change is the catalyst that kicks vmPFC into a higher gear and effects adaptive change (i.e., persistence)...when negative affect accompanies uncontrollable setbacks, as is often the case, the vmPFC activity is necessary to adapt to the emotional reaction and, in so doing, preserve persistence.

The ventral striatum on the other hand is important for signaling prediction errors when behavioral outcomes do not match our expectations...when we believe we have control over situations, the ventral striatum can use value signals to motivate future behavior...this striatal effect is problem focused compared to the prefrontal effect that is more emotion focused.

A fetching point about Paul Whalen's and William Kelley's review is that it starts with the example of two professors currently employed at Dartmouth College.

One applied, and he was hired on his very first try (we’ll call him Bill in this example). Imagine that the other; well, he needed more chances before his eventual hire (we’ll call him P.W. to protect his identity). What dictates whether someone will persist when they encounter a setback? Is it the person who remains calm in the moment, not letting this single event rattle her? Or is it the person who reacts strongly to defeat and heavily reinvests in the project, determined to change things the next time? To borrow from Shakespeare, tell us where is persistence bred, or in the heart, or in the head (The Merchant of Venice, 3.2)? ...Bhanji and Delgado (2014) provide clear evidence of the latter.

Guess who Bill and P.W. actually are!

Another magic anti-aging compound?

Riluzole is a drug used to treat amyotrophic lateral sclerosis, also studied for use in mood and anxiety disorders, depression and obsessive-compulsive disorder. It also can have some nasty side effects (nausea,weakness, decreased lung function).

 
Pereira et al. now show that it has a dramatic effect in preventing cognitive decline in aged rats:

The dementia of Alzheimer’s disease (AD) results primarily from degeneration of neurons that furnish glutamatergic corticocortical connections that subserve cognition. Although neuron death is minimal in the absence of AD, age-related cognitive decline does occur in animals as well as humans, and it decreases quality of life for elderly people. Age-related cognitive decline has been linked to synapse loss and/or alterations of synaptic proteins that impair function in regions such as the hippocampus and prefrontal cortex. These synaptic alterations are likely reversible, such that maintenance of synaptic health in the face of aging is a critically important therapeutic goal. Here, we show that riluzole can protect against some of the synaptic alterations in hippocampus that are linked to age-related memory loss in rats. Riluzole increases glutamate uptake through glial transporters and is thought to decrease glutamate spillover to extrasynaptic NMDA receptors while increasing synaptic glutamatergic activity. Treated aged rats were protected against age-related cognitive decline displayed in nontreated aged animals. Memory performance correlated with density of thin spines on apical dendrites in CA1, although not with mushroom spines. Furthermore, riluzole-treated rats had an increase in clustering of thin spines that correlated with memory performance and was specific to the apical, but not the basilar, dendrites of CA1. Clustering of synaptic inputs is thought to allow nonlinear summation of synaptic strength. These findings further elucidate neuroplastic changes in glutamatergic circuits with aging and advance therapeutic development to prevent and treat age-related cognitive decline.

Human children conform to peers' behavior, but apes do not.

Haun and collaborators make the interesting observation that two year old human children will change a learned problem solving strategy on observing peers performing an alternative strategy; apes do not show this behavior.

All primates learn things from conspecifics socially, but it is not clear whether they conform to the behavior of these conspecifics—if conformity is defined as overriding individually acquired behavioral tendencies in order to copy peers’ behavior. In the current study, chimpanzees, orangutans, and 2-year-old human children individually acquired a problem-solving strategy. They then watched several conspecific peers demonstrate an alternative strategy. The children switched to this new, socially demonstrated strategy in roughly half of all instances, whereas the other two great-ape species almost never adjusted their behavior to the majority’s. In a follow-up study, children switched much more when the peer demonstrators were still present than when they were absent, which suggests that their conformity arose at least in part from social motivations. These results demonstrate an important difference between the social learning of humans and great apes, a difference that might help to account for differences in human and nonhuman cultures.

Personality and Ideology

I've done a number of posts (for example, here) pointing to work suggesting that differences in basic partially inherited neurocognitive traits (such as flexibility and openness versus caution and rule following) might underlie liberal versus conservative personalities. Malka et al. have done a cross national test, analyzing responses from more than 70,000 people from 51 countries to ask how a conservative personality style actually relates to cultural and economic attitudes. From their review of the work:

...we found that people with a conservative personality did indeed tend to adopt culturally conservative attitudes on matters like abortion, homosexuality and immigration. On this count, the rigidity of the right model seems to be valid.

But when it came to economic matters related to social welfare policy and economic intervention — the central feature of the left-right divide in much of the world — the results were far different. People with a conservative personality tended to lean slightly to the left...a conservative personality might actually pull people in two directions with respect to their economic attitudes. Prioritizing order and stability will lead to a yearning for the security that left-wing economic policies aim to provide.

This left leaning tendency can be extinguished, however, among people who are highly attentive to politics in countries in which left-right conflict is prominent, by political messaging that binds together right wing cultural and economic views under a broad "conservative" banner. This has nothing to do with psychological predispositions, and suggests that changing the packaging or messaging could change behaviors.

Subliminal Strengthening

Levy et al. make the interesting observation that presenting subliminal positive age stereotypes to older people has a greater effect than similar explicit interventions:

Negative age stereotypes that older individuals assimilate from their culture predict detrimental outcomes, including worse physical function. We examined, for the first time, whether positive age stereotypes, presented subliminally across multiple sessions in the community, would lead to improved outcomes. Each of 100 older individuals (age = 61–99 years, M = 81) was randomly assigned to an implicit-positive-age-stereotype-intervention group, an explicit-positive-age-stereotype-intervention group, a combined implicit- and explicit-positive-age-stereotype-intervention group, or a control group. Interventions occurred at four 1-week intervals. The implicit intervention strengthened positive age stereotypes, which strengthened positive self-perceptions of aging, which, in turn, improved physical function. The improvement in these outcomes continued for 3 weeks after the last intervention session. Further, negative age stereotypes and negative self-perceptions of aging were weakened. For all outcomes, the implicit intervention’s impact was greater than the explicit intervention’s impact. The physical-function effect of the implicit intervention surpassed a previous study’s 6-month-exercise-intervention’s effect with participants of similar ages. The current study’s findings demonstrate the potential of directing implicit processes toward physical-function enhancement over time.

The study they cite as showing less effect of exercise than subliminal priming used the same standard "Short Physical Performance Battery" to assess changes in physical ability caused by the interventions. This test assesses strength, gait, and balance by examining (a) time to rise from a chair and return to the seated position five times, (b) time to walk 8 feet, and (c) ability to stand with feet together in the side-by-side, semi-tandem, and tandem positions for 10 s. Possible scores range from 0 to 12, with a higher score indicating better physical performance. Older individuals who receive lower scores on this measure have increased risk of disability, nursing-home placement, and mortality.

Personality and immune system reactivity.

Vedhara et al. have examined the expression of inflammatory genes in 121 people who also took personality tests that rated the generally identified five major dimensions of human personality (Neuroticism, Extraversion, Openness to Experience, Agreeableness, and Conscientiousness). From the author's introduction:

...we hypothesized that pro-inflammatory gene expression would be up-regulated in extraverts and people with high levels of openness to experience (both of whom would be expected to experience elevated risk of injury/infection) and down-regulated in conscientious individuals with comparatively strong behavioural immune responses.

This is in fact what they found. From their discussion:

The present results identified systematic differences in leukocyte gene expression that correlate with individual differences on two major dimensions of human personality: Extraversion and Conscientiousness. Consistent with predictions from behavioural immune response theory, Extraversion was associated with up-regulated expression of pro-inflammatory genes, whereas Conscientiousness was associated with down-regulated expression of pro-inflammatory genes. These effects were independent of major health behavioural factors (BMI, smoking, alcohol consumption, physical activity); independent of variations in leukocyte subset prevalence; independent of negative affect; independent of minor physical symptoms and related medications; and independent of demographic characteristics as well as other major dimensions of human personality. In contrast, none of the major personality dimensions was significantly associated with differential expression of the other primary gene module involved in the CTRA profile – antiviral and antibody-related transcripts. In the context of previous data linking Extraversion and Conscientiousness to health and longevity, the present functional genomics findings may provide new insights into the molecular basis for such relationships.

Their results do not support the model of neuroticism and negative affect generating a 'disease-prone personality.' Numerous other studies have correlated the trait of conscientiousness with longevity.

The unforeseen costs of extraordinary experiences.

Daniel Gilbert and his collaborators at Harvard have come up with yet another fascinating nugget on our human behaviors:

People seek extraordinary experiences—from drinking rare wines and taking exotic vacations to jumping from airplanes and shaking hands with celebrities. But are such experiences worth having? We found that participants thoroughly enjoyed having experiences that were superior to those had by their peers, but that having had such experiences spoiled their subsequent social interactions and ultimately left them feeling worse than they would have felt if they had had an ordinary experience instead. Participants were able to predict the benefits of having an extraordinary experience but were unable to predict the costs. These studies suggest that people may pay a surprising price for the experiences they covet most.

A bit from the introduction:

More than 600 people have paid a minimum of $250,000 for a seat on the world’s first commercial spacecraft, soon to be launched by Virgin Galactic. Their journey will last a few hours, but they will talk about it for years to come...Floating weightless for several minutes while gazing down at Earth is an experience that falls somewhere between delightful and dazzling, which is why so many people are willing to pay so much money to have it. The less obvious consequence is that such experiences can make the people who have them strangers to everyone else on earth—and, as a rule, earthlings do not always treat strangers so nicely. At worst, people may be envious and resentful of those who have had an extraordinary experience, and at best, they may find themselves with little to talk about. Indeed, when people interact, they typically discuss the things they have in common and an afternoon in orbit typically is not one of them. Extraordinary experiences are both different from and better than the experiences that most other people have, and being both alien and enviable is an unlikely recipe for popularity.

In one experiment subjects in groups watched a video (17 groups of 4 participants, each watching in their own cubicle - afterwards they were escorted to a room for 5 min of unstructured conversation. One of the participants in each group watched a video that was superior to the video watched by the others. Participants who had watched the superior movie felt more enjoyment just after the film, but felt excluded during a subsequent social interaction, and this left them feeling worse than participants who had had an ordinary experience instead. A second experiment showed that participants correctly predicted that the extraordinary experience would leave them feeling better than the ordinary experience would before the interaction, but failed to realize that it would leave them feeling worse after the interaction. In a final study participants were asked to estimate how the actual participants in Study 1 felt. The result found was that they did not expect the extraordinary experiencer to be excluded from the interaction, and they expected the extraordinary experiencer to feel better—not worse—than the ordinary experiencers.

From the summary:

Pleasures come in two varieties: the social and the nonsocial. A hallmark of the nonsocial pleasures—whether the cool tingle of Dom Pérignon or the hot snarl of a new Maserati—is that people adapt to them quickly, which is why such experiences are typically best when they are novel or rare. The social pleasures have a different appeal. People crave acceptance, belonging, and camaraderie, and the hallmark of these pleasures is that they come more readily to those who fit in than to those who stand out. The two varieties of pleasure give rise to a pair of incompatible desires: to do what other people have not yet done and to be just like everyone else. Satisfying the first of these desires can frustrate the second. When extraordinary experiences separate a person from others, these experiences may ultimately reclaim more joy than they provide.

Invunerablism

Todd May does a brief essay (coining the world “invulnerabilism”) that is yet another interesting take on an issue central to all our lives: Do what degree is it useful to psychologically armor ourselves from the ‘slings and arrows of outrageous fortune’ - to have a strong psychological immune system, or an emotionally invulnerable self construal? The meditative practices of several traditions offer us a route into our brain’s ‘basement’, a closer approach to and experience of the machinery that generates all the stuff upstairs, our emotionally reactive immersed selves and personas (Buddhism, for example, offering us an end to suffering if we abandon our desires.) May suggests:

..the way to think about these things has less to do with the invulnerability promoted by the official doctrines, and more to do with, one might say, using these doctrines to take the edge off of vulnerability, to allow one to experience life without becoming overwhelmed or depressed or resentful or bitter, except perhaps at the extremity of loss. There is some combination of embedding oneself in the world in a vulnerable way and not being completely undone by that vulnerability that is pointed at, if not directly endorsed, by the official doctrines.

It seems to me that Taoism, Buddhism, Stoicism, etc. work not by making one invulnerable but rather by allowing one to step back from the immediacy of the situation so that the experience of pain or suffering is seen for what it is, precisely as part of a contingent process, a process that could have yielded a very different present but just happened to yield this one.

Another point would be the evolution of our social brain has resulted in a built in bias towards feeling the sort of vulnerability and bonding that sustains and defends social group identity. A group of floating detached Taoists isn't all that useful in intergroup conflicts. Finally, disciplines that result in maintaining emotional distance from others can also let atrophy the evolved neuroendocrine chemistries that can vitalize our physiology and longevity.