Sleep cleans our brains, renews our synapses, consolidates our memories

This bit of work got a flurry of attention recently, but I think is important enough to warrant repeating here.  Xie et al.  have used an elegant two-photon imaging technique to compare awake and sleeping mouse brains. They find that metabolic waste products of neural activity are cleared out of the sleeping brain at a faster rate than during the awake state:

...convective fluxes of interstitial fluid increased the rate of β-amyloid clearance during sleep. Thus, the restorative function of sleep may be a consequence of the enhanced removal of potentially neurotoxic waste products that accumulate in the awake central nervous system.

The review of this work by Underwood has a nice graphic of the fluid-filled channels (pale blue) that expand to flush out waste:

The role of sleep in memory consolidation is well known, and further work of Tononi's group has suggested that in rats, sleep maintains an overall synaptic balance, by uniformly dialing down synapses that have expanded their activity during the day. (I have also previously pointed to work on fruit flies by Tononi's group coming to a similar conclusion.)

Work of this sort suggests that the 50-70 million Americans who have insufficient sleep or some kind of sleep disorder (like sleep apnea) are carrying around extra garbage in their brains during the day and have brain synaptic connection that haven't recovered from previous days' activities, both factors that would seem likely to compromise our mental function!

Scary music for Halloween - Dance Macabre

You should have a look at the 13 scariest pieces of classical music for Halloween, assembled by Limelight Magazine. It is hard for me to select a favorite, but I will point to this classic Disney cartoon of Saint-Saens Dance Macabre:

Saint-Saëns’s creepy 1874 tone poem is a Halloween classic, depicting the revelry of the Grim Reaper at midnight every year at this time. With his cursed fiddle, Death summons the dead from their graves to kick up their heals until dawn. In this vintage Disney animation, listen out for the xylophone sound of rattling bones.

Finding a protein linking exercise to brain health

Yet another candidate for a life enhancing drug? ...perhaps a protein that mimics the effect of the protein FNDC5, which is produced by muscular exertion and in turn boosts the level of a brain-health protein, BDNF (brain-derived neurotrophic protein) in the dentate gyrus of the hippocampus. Here is the summary and abstract from Wrann et al. with some technical details:

Highlights

Exercise induces FNDC5 in the hippocampus.

PGC-1α regulates neuronal Fndc5 gene expression in vitro and in vivo.

FNDC5 positively regulates the expression of the important neurotrophin BDNF.

Peripheral delivery of FNDC5 via adenoviral vectors induces Bdnf in the hippocampus.

Summary

Exercise can improve cognitive function and has been linked to the increased expression of brain-derived neurotrophic factor (BDNF). However, the underlying molecular mechanisms driving the elevation of this neurotrophin remain unknown. Here we show that FNDC5, a previously identified muscle protein that is induced in exercise and is cleaved and secreted as irisin, is also elevated by endurance exercise in the hippocampus of mice. Neuronal Fndc5 gene expression is regulated by PGC-1α, and Pgc1a−/− mice show reduced Fndc5 expression in the brain. Forced expression of FNDC5 in primary cortical neurons increases Bdnf expression, whereas RNAi-mediated knockdown of FNDC5 reduces Bdnf. Importantly, peripheral delivery of FNDC5 to the liver via adenoviral vectors, resulting in elevated blood irisin, induces expression of Bdnf and other neuroprotective genes in the hippocampus. Taken together, our findings link endurance exercise and the important metabolic mediators, PGC-1α and FNDC5, with BDNF expression in the brain.

"Only Disconnect" - The pathology of digital of connectivity

Alas, it seems increasingly clear that to follow E.M. Forster’s dictum “Only Connect” (i.e. with humans in person, what our emotional brain evolved to do.) it is also necessary to follow Evgeny Morozov’s more recent dictum (and title of his review of several several books) “Only Disconnect.” (with the pseudo-connectivity of our tweets,followers, facebook friends, blog hits, google+ plus counts, Klout numbers, Thumbs up or downs, Shout outs, Likes, etc.). I will pass on some clips from Morozov's article. After noting descriptions by the Weimar Republic's literary luminary Siegfried Kracauer of the public over stimulation of his day, and his remedy of 'radical boredom' as an antidote, Morozov continues:

These days, "the state of permanent receptivity" has become the birthright of anyone with a smartphone. We are under constant assault by "interestingness"...the anti-boredom lobby has all but established its headquarters in Silicon Valley...

Information overload can bore us as easily as information underload. But this form of boredom, mediated boredom, doesn't provide time to think; it just produces a craving for more information in order to suppress it.

Morozov quotes from French philosopher Henri Lefebvre from the early 1960's

Today everything comes to an end virtually as soon as it begins, and vanishes almost as soon as it appears..As interest in it gets progressively weaker, so news becomes more rapid and concentrated, until finally, at the end of a shorter and shorter period, it wears itself..We have the phoney "new" faked novelty..The confusion between triviality which no longer appears trivial and sensationalism which is made to appear ordinary is cleverly organized. New shrinks to the size of the socially instantaneous, and the immediate instant tends to disappear in an instant which has already passed.

And then, Morozov notes:

I should admit that I'm something of a "contemplative computing" devotee, which is also to say, a distraction addict. Last year, I bought a safe with a built-in timer that I use to lock away my smartphone and Internet cable for days on end. (Tools like Freedom didn't work for me - they are too easy to circumvent.

What's needed is a modern-day counterpart to the anti-noise campaigners of a century ago.. Information deserve its own environmentalism....what is modernity if not a collection of pickets of silence and distraction? Consider the Amtrak train: yes, we get Wi-Fi, but we also get the Quiet Car..Both radical boredom and radical distraction can get us closer to "authentic rapture within the inauthentic domain." The trick is not to settle for their tepid, mediocre versions.

Likewise, the possibility of controlled disconnection - embedded in software like Freedom and harware like my safe - reassures us that our task lists and deadlines are manageable, if we approach them with distraction. Like travel and dance, both are illusions concocted by modernity... Life in the New Digital Age might be disorienting, but at least it isn't nasty, brutish, and short. Not in the Quiet Car, anyway.

Perspective taking can turn competitors unethical

An interesting bit from Pierce et al.:

Perspective taking is often the glue that binds people together. However, we propose that in competitive contexts, perspective taking is akin to adding gasoline to a fire: It inflames already-aroused competitive impulses and leads people to protect themselves from the potentially insidious actions of their competitors. Overall, we suggest that perspective taking functions as a relational amplifier. In cooperative contexts, it creates the foundation for prosocial impulses, but in competitive contexts, it triggers hypercompetition, leading people to prophylactically engage in unethical behavior to prevent themselves from being exploited. The experiments reported here establish that perspective taking interacts with the relational context—cooperative or competitive—to predict unethical behavior, from using insidious negotiation tactics to materially deceiving one’s partner to cheating on an anagram task. In the context of competition, perspective taking can pervert the age-old axiom “do unto others as you would have them do unto you” into “do unto others as you think they will try to do unto you.”

Oxytocin, gentle human touch, and social impression.

Another bit of information from Leknes and collaborators, expanding on their work mentioned in a recent post:

Interpersonal touch is frequently used for communicating emotions, strengthen social bonds and to give others pleasure. The neuropeptide oxytocin increases social interest, improves recognition of others’ emotions, and it is released during touch. Here, we investigated how oxytocin and gentle human touch affect social impressions of others, and vice versa, how others’ facial expressions and oxytocin affect touch experience. In a placebo-controlled crossover study using intranasal oxytocin, 40 healthy volunteers viewed faces with different facial expressions along with concomitant gentle human touch or control machine touch, while pupil diameter was monitored. After each stimulus pair, participants rated the perceived friendliness and attractiveness of the faces, perceived facial expression, or pleasantness and intensity of the touch. After intranasal oxytocin treatment, gentle human touch had a sharpening effect on social evaluations of others relative to machine touch, such that frowning faces were rated as less friendly and attractive, whereas smiling faces were rated as more friendly and attractive. Conversely, smiling faces increased, whereas frowning faces reduced, pleasantness of concomitant touch – the latter effect being stronger for human touch. Oxytocin did not alter touch pleasantness. Pupillary responses, a measure of attentional allocation, were larger to human touch than to equally intense machine touch, especially when paired with a smiling face. Overall, our results point to mechanisms important for human affiliation and social bond formation.

A genetic predisposition to note the negative.

Another interesting example of viewing the world through gene-colored glasses...Todd et al. note an interesting behavioral correlation involving a gene variant, carried by ~50% of Caucasians, of subtype B of the α2-adrenergic receptor: people with the variant are more likely to take note of negative events. They use the "attentional blink" paradigm to reach this conclusion:

The attentional blink...is a phenomenon in which participants are typically unable to identify a target stimulus when it is presented less than approximately 500 ms after a previous target in a rapid stream of stimuli. One interpretation of this blink is that it reflects a failure of attentional filters to consolidate the second target into working memory when it appears too quickly after the first, which results in impaired perceptual awareness. When the second target has emotional significance, there is a reduced attentional blink, or an emotional sparing. This emotional sparing, or reduction of the attentional blink for emotional stimuli relative to neutral stimuli, can be seen as the relative tuning of selective attention to affective stimuli.

Here is their abstract (which contains the fairly common error of using "are responsible for" instead of the more correct "correlate with"):

Emotionally enhanced memory and susceptibility to intrusive memories after trauma have been linked to a deletion variant (i.e., a form of a gene in which certain amino acids are missing) of ADRA2B, the gene encoding subtype B of the α2-adrenergic receptor, which influences norepinephrine activity. We examined in 207 participants whether variations in this gene are responsible for individual differences in affective influences on initial encoding that alter perceptual awareness. We examined the attentional blink, an attentional impairment during rapid serial visual presentation, for negatively arousing, positively arousing, and neutral target words. Overall, the attentional blink was reduced for emotional targets for ADRA2B-deletion carriers and noncarriers alike, which reveals emotional sparing (i.e., reduction of the attentional impairment for words that are emotionally significant). However, deletion carriers demonstrated a further, more pronounced emotional sparing for negative targets. This finding demonstrates a contribution of genetics to individual differences in the emotional subjectivity of perception, which in turn may be linked to biases in later memory.

Silver Lining of a mind in the clouds

This post continues a MindBlog thread on the consequences of our minds being task-focused versus wandering. A seminal paper was Killingsworth and Gilbert's 2010 work "A Wandering Mind is an Unhappy Mind.", and I recently posted a more positive view. Franklin et al. now collect data of the sort Killingsworth and Gilbert used, but analyze with a bit more nuance:

The negative effects of mind-wandering on performance and mood have been widely documented. In a recent well-cited study, Killingsworth and Gilbert (2010) conducted a large experience sampling study revealing that all off-task episodes, regardless of content, have equal to or lower happiness ratings, than on-task episodes. We present data from a similarly implemented experience sampling study with additional mind-wandering content categories. Our results largely conform to those of the Killingsworth and Gilbert (2010) study, with mind-wandering generally being associated with a more negative mood. However, subsequent analyses reveal situations in which a more positive mood is reported after being off-task. Specifically when off-task episodes are rated for interest, the high interest episodes are associated with an increase in positive mood compared to all on-task episodes. These findings both identify a situation in which mind-wandering may have positive effects on mood, and suggest the possible benefits of encouraging individuals to shift their off-task musings to the topics they find most engaging.

Face recognition area of the brain also notes race and sex.

Hundreds of papers have been written on the fusiform face area (FFA) of our brains, which Contreras et al. now show immediately collects information about race and sex as well, showing patterns of activation that are different for black and white faces, and for female and male faces. Meaning is attached to those identifications later in visual processing. This specialization might have appeared for evolutionary or developmental reasons, for it can be important to know the sex and race of other people, especially in contexts in which those differences should change the way in which you interact with them. Here is their abstract:

Although prior research suggests that fusiform gyrus represents the sex and race of faces, it remains unclear whether fusiform face area (FFA)–the portion of fusiform gyrus that is functionally-defined by its preferential response to faces–contains such representations. Here, we used functional magnetic resonance imaging to evaluate whether FFA represents faces by sex and race. Participants were scanned while they categorized the sex and race of unfamiliar Black men, Black women, White men, and White women. Multivariate pattern analysis revealed that multivoxel patterns in FFA–but not other face-selective brain regions, other category-selective brain regions, or early visual cortex–differentiated faces by sex and race. Specifically, patterns of voxel-based responses were more similar between individuals of the same sex than between men and women, and between individuals of the same race than between Black and White individuals. By showing that FFA represents the sex and race of faces, this research contributes to our emerging understanding of how the human brain perceives individuals from two fundamental social categories.

Out of the group, out of control?

From Otten and Jonas:

The effects of social exclusion are far-reaching, both on an emotional and behavioral level. The present study investigates whether social exclusion also directly influences basic cognitive functions, specifically the ability to exert cognitive control. Participants were either excluded or included while playing an online game. To test whether exclusion altered cognitive control, we measured the electrophysiological responses to a Go/No Go task. In this task participants had to withhold a response (No Go) on a small number of trials while the predominant tendency was to make an overt (Go) response. Compared to Go trials the event-related potential evoked by No Go trials elicited an increased N2, reflecting the detection of the response conflict, followed by an increased P3, reflecting the inhibition of the predominant response. The N2 effect was larger for participants who had experienced exclusion, while the P3 effect was smaller. This indicates that exclusion leads to an increased ability to detect response conflicts, while at the same time exclusion decreases the neural processes that underlie the inhibition of unwanted behavior.

Trashing Malcolm Gladwell

It is with some glee that I have been reading the many negative reviews of Malcolm Gladwell's most recent book (David and Goliath..), in particular Chad Orzel's "Malcolm Gladwell Is Deepak Chopra." He compares Gladwell's style to that of Deepak Chopra, who I immediately decided was a con-artist when I first encountered his work in the 1970s. After noting Gladwell's willful misleading of readers with cherry-picked science, Orzel notes the connection to Chopra:

So what does this have to do with everybody’s favorite bullshit artist stand-up Eastern philosopher? It occurred to me in reading some of the social media reactions that Gladwell stands in relation to good, responsible journalists in more or less the same position that Chopra stands in relation to actual quantum physicists. That is, he’s a glib and gifted writer who can talk just enough of the talk to buffalo people from outside the field. To a physicist, Chopra’s babble about “energy fields” and “congealing quantum soup” presents as utter gibberish, but he drops enough names and technical terms to sound superficially like somebody with real knowledge of physics, making it really hard for those of us who really know how the universe works to convince non-scientists that he doesn’t. If both sides throw around technical terms, but one twists them into a compelling narrative while the other is full of limits and caveats and, you know, math, well, the fact that the people with the complicated story are right doesn’t carry as much weight as it ought to.

A few further writeups are Poole's review relayed in The New Republic, and Chabris in Slate.

Constructive aspects of mind wandering

I've generally been noting research that documents some negative aspects of mind wandering, for example "A wandering mind is an unhappy mind" and "Better memory with less default mode activity." The other side of the coin, how day dreaming can be constructive, is developed by Kaufman here and here(PDF). He and his coauthors point out that the rewards of mind wandering:

...include self- awareness, creative incubation, improvisation and evaluation, memory consolidation, autobiographical planning, goal driven thought, future planning, retrieval of deeply personal memories, reflective consideration of the meaning of events and experiences, simulating the perspective of another person, evaluating the implications of self and others’ emotional reactions, moral reasoning, and reflective compassion

Kaufman argues for an definition of intelligence moves beyond emphasis on cognitive control, deliberate planning, and decontextualized problem solving, and that includes:

...an individual’s personal goals, and considers both controlled forms of cognition (e.g., working memory, attentional focus, etc.) and spontaneous forms of cognition (e.g., intuition, affect, insight, implicit learning, latent inhibition, and the spontaneous triggering of episodic memories and declarative knowledge) are important potential contributors to that personal adaptation.

The changing psychology of culture from 1800 through 2000.

Greenfield makes use of the Google Books Ngram Viewer to observe a large shift from collectivist to individualist values during this period, as mass migration occurred from rural to urban areas. The corpus of books published in England and America was examined for the frequency of words like “obliged” and “choose”;“give” and “get”;“act” and “feel”, etc. Their abstract:

The Google Books Ngram Viewer allows researchers to quantify culture across centuries by searching millions of books. This tool was used to test theory-based predictions about implications of an urbanizing population for the psychology of culture. Adaptation to rural environments prioritizes social obligation and duty, giving to other people, social belonging, religion in everyday life, authority relations, and physical activity. Adaptation to urban environments requires more individualistic and materialistic values; such adaptation prioritizes choice, personal possessions, and child-centered socialization in order to foster the development of psychological mindedness and the unique self. The Google Ngram Viewer generated relative frequencies of words indexing these values from the years 1800 to 2000 in American English books. As urban populations increased and rural populations declined, word frequencies moved in the predicted directions. Books published in the United Kingdom replicated this pattern. The analysis established long-term relationships between ecological change and cultural change.

Distinctive brain correlates of brief compassion meditation.

This article by Hassenkamp provides a very useful integrative review of, and links to, several articles on brain correlates of mindfulness, empathy, and compassion meditation that I have noted separately in previous posts. It is becoming increasingly clear that even brief engagement with training or practice of compassion meditation enhances both perception of the emotional state of others and activity of the brain's networks related to love, affiliation, and positive emotion. Hassenkamp notes that the studies:

...highlight the important difference between merely having empathy, which can lead to negative emotions and even feelings of helplessness and burnout, versus compassion, which is rooted in loving, affiliative, positive feelings, and fosters a motivation to help. When faced with intense suffering, these findings could have major implications for strategies to overcome empathic distress and strengthen resilience, not to mention promoting helpful action.

Is music the key to success?

I'm passing this on immediately after reading it. While I have done numerous posts on how music training influences brain development, for example to enhance and speed brain processing of complex inputs into complex motor outputs, this article by Joanne Lipman points to other straightforward reasons that musical training and continued practice as a adult correlates with high achievement, with high achievers noting qualities that:

...music has sharpened: collaboration, creativity, discipline and the capacity to reconcile conflicting ideas. All are qualities notably absent from public life. Music may not make you a genius, or rich, or even a better person. But it helps train you to think differently, to process different points of view — and most important, to take pleasure in listening.

Oxytocin dilates our pupils and enhances emotion detection

Interesting work from Leknes et al.:

Sensing others’ emotions through subtle facial expressions is a highly important social skill. We investigated the effects of intranasal oxytocin treatment on the evaluation of explicit and ‘hidden’ emotional expressions and related the results to individual differences in sensitivity to others’ subtle expressions of anger and happiness. Forty healthy volunteers participated in this double-blind, placebo-controlled crossover study, which shows that a single dose of intranasal oxytocin (40 IU) enhanced or ‘sharpened’ evaluative processing of others’ positive and negative facial expression for both explicit and hidden emotional information. Our results point to mechanisms that could underpin oxytocin’s prosocial effects in humans. Importantly, individual differences in baseline emotional sensitivity predicted oxytocin’s effects on the ability to sense differences between faces with hidden emotional information. Participants with low emotional sensitivity showed greater oxytocin-induced improvement. These participants also showed larger task-related pupil dilation, suggesting that they also allocated the most attentional resources to the task. Overall, oxytocin treatment enhanced stimulus-induced pupil dilation, consistent with oxytocin enhancement of attention towards socially relevant stimuli. Since pupil dilation can be associated with increased attractiveness and approach behaviour, this effect could also represent a mechanism by which oxytocin increases human affiliation.

Our sense of fairness changes with weak electric stimulation of our prefrontal cortex.

Fascinating work from Ruff et al:

All known human societies have maintained social order by enforcing compliance with social norms. The biological mechanisms underlying norm compliance are, however, hardly understood. We show that the right lateral prefrontal cortex (rLPFC) is involved in both voluntary and sanction-induced norm compliance. Both types of compliance could be changed by varying neural excitability of this brain region with transcranial direct current stimulation, but they were affected in opposite ways, suggesting that the stimulated region plays a fundamentally different role in voluntary and sanction-based compliance. Brain stimulation had a particularly strong effect for compliance based on socially constituted sanctions, while it left beliefs about what the norm prescribes and about subjectively expected sanctions unaffected. Our findings suggest that rLPFC activity is a key biological prerequisite for an evolutionarily and socially important aspect of human behavior.

(Culotta does a brief review here.)

Psychedelic drugs cause cortical desynchronization

From Muthukumaraswamy et al., small wonder that it doesn't all hang together during the psychedelic experience:

Psychedelic drugs produce profound changes in consciousness, but the underlying neurobiological mechanisms for this remain unclear. Spontaneous and induced oscillatory activity was recorded in healthy human participants with magnetoencephalography after intravenous infusion of psilocybin—prodrug of the nonselective serotonin 2A receptor agonist and classic psychedelic psilocin. Psilocybin reduced spontaneous cortical oscillatory power from 1 to 50 Hz in posterior association cortices, and from 8 to 100 Hz in frontal association cortices. Large decreases in oscillatory power were seen in areas of the default-mode network. Independent component analysis was used to identify a number of resting-state networks, and activity in these was similarly decreased after psilocybin. Psilocybin had no effect on low-level visually induced and motor-induced gamma-band oscillations, suggesting that some basic elements of oscillatory brain activity are relatively preserved during the psychedelic experience. Dynamic causal modeling revealed that posterior cingulate cortex desynchronization can be explained by increased excitability of deep-layer pyramidal neurons, which are known to be rich in 5-HT2A receptors. These findings suggest that the subjective effects of psychedelics result from a desynchronization of ongoing oscillatory rhythms in the cortex, likely triggered by 5-HT2A receptor-mediated excitation of deep pyramidal cells.

Poulenc Improvisation No. 15

This piece is a homage to Edith Piaf.  The last of a series of Poulenc recordings I have done this year.

 

Better memory with less default mode activity

I've done a number of posts on our default mode versus attentional networks (a review is here, for example). Here is the summary and abstract for some interesting work in NeuroImage by Chai et al. on the relationship of these modes to memory:

Highlights:

-Children, adolescents and adults studied scenes during fMRI.
-Default-mode network (DMN) deactivation was examined during memory encoding.
-DMN deactivation was associated with successful memory encoding in adults.
-In children, deactivation of the DMN did not predict memory outcome. 

Abstract:

Task-induced deactivation of the default-mode network (DMN) has been associated in adults with successful episodic memory formation, possibly as a mechanism to focus allocation of mental resources for successful encoding of external stimuli. We investigated developmental changes of deactivation of the DMN (posterior cingulate, medial prefrontal, and bilateral lateral parietal cortices) during episodic memory formation in children, adolescents, and young adults (ages 8–24), who studied scenes during functional magnetic resonance imaging (fMRI). Recognition memory improved with age. We defined DMN regions of interest from a different sample of participants with the same age range, using resting-state fMRI. In adults, there was greater deactivation of the DMN for scenes that were later remembered than scenes that were later forgotten. In children, deactivation of the default-network did not differ reliably between scenes that were later remembered or forgotten. Adolescents exhibited a pattern of activation intermediate to that of children and adults. The hippocampal region, often considered part of the DMN, showed a functional dissociation with the rest of the DMN by exhibiting increased activation for later remembered than later forgotten scene that was similar across age groups. These findings suggest that development of memory ability from childhood through adulthood may involve increased deactivation of the neocortical DMN during learning.

Evilicious humans, hard-wired for war?

"Evilicious" is the title of a new book self published by Marc Hauser, the Harvard Psychologist forced to resign his position after it was discovered that he had been falsifying behavioral data to fit his foregone conclusions. He asks "why seemingly normal people torture, mutilate, and kill others for the fun of it — or for no apparent benefit at all." He suggests that humans uniquely evolved this capacity because "evildoers emerge when unsatisfied desires combine with the denial of reality, enabling individuals to engage in gratuitous cruelty toward innocent victims. This simple recipe is part of human nature, and part of our brain’s uniquely evolved capacity to combine different thoughts and emotions." Hauser's 'trying for a second chance' book has drawn a number of favorable reviews. One summary from Atran's review cited by Dobbs:

....“addiction to evil” – the persistent subjection of innocents to gratuitous cruelty — emerged as a by-product of the human brain’s unique evolutionary design. The ability to creatively combine all manner of thought and emotion enabled our species to produce great works of art and science, as well as to freely choose to kill and torture with a level of maliciousness unprecedented in the history of life on earth. Here we find that the most dangerous and effective evildoers are not sadists or serial killers with disordered minds, but mostly normal people who could have chosen not to kill and torture. When driven by unsatisfied desires — especially if channeled into dreams of glory for a cause — and in denying the reality and the humanity of others, even nice guys can become massively bloodthirsty.

A related issue is whether we are "hard-wired for war". Evolutionary biologist David Barash argues there is no convincing evidence for this. Despite examples such as Yanomamo ferocity, a broad survey shows that peacemaking is, if anything, more pronounced and widely distributed, especially among groups of nomadic foragers who are probably closest in ecological circumstance to our hominin ancestors.

Information sharing as a measure of brain consciousness

King et al. make measurements they suggest are a signature of conscious state in awake but noncommunicating patients. I pass on the summary, abstract, and one of their figures (and, the first graphic, thanks to Jean-Rémi King, who offers the unedited PDF of the article here):

Highlights
 • Theories of consciousness link conscious access to global information integration
 • 181 EEG recordings were acquired, including 143 from VS and MCS patients
 • Information sharing across current sources was estimated with a new measure
 • The results suggest that unconscious patients have lower global information sharing

Summary

Neuronal theories of conscious access tentatively relate conscious perception to the integration and global broadcasting of information across distant cortical and thalamic areas. Experiments contrasting visible and invisible stimuli support this view and suggest that global neuronal communication may be detectable using scalp electroencephalography (EEG). However, whether global information sharing across brain areas also provides a specific signature of conscious state in awake but noncommunicating patients remains an active topic of research. We designed a novel measure termed “weighted symbolic mutual information” (wSMI) and applied it to 181 high-density EEG recordings of awake patients recovering from coma and diagnosed in various states of consciousness. The results demonstrate that this measure of information sharing systematically increases with consciousness state, particularly across distant sites. This effect sharply distinguishes patients in vegetative state (VS), minimally conscious state (MCS), and conscious state (CS) and is observed regardless of etiology and delay since insult. The present findings support distributed theories of conscious processing and open up the possibility of an automatic detection of conscious states, which may be particularly important for the diagnosis of awake but noncommunicating patients.

Figure - wSMI Increases with Consciousness, Primarily over Centroposterior Regions(A) The median wSMI that each EEG channel shares with all other channels is depicted for each state of consciousness.(B) 120 pairs formed by 16 clusters of EEG channels are depicted as 3D arcs whose height is proportional to the Euclidian distance separating the two clusters. Line color and thickness are proportional to the mean wSMI shared by the corresponding cluster pair.

Early emergence of mature brain alarm circuits in maternally deprived children

Many studies have shown adverse effects of various kinds of childhood deprivation or abuse, with maternal deprivation being one of the most significant. Normally, medial prefrontal cortex (mPFC) connections with the amygdala are immature during childhood and become adult-like during adolescence. Gee et al. show that institutionalized youths who experienced early maternal deprivation show mature connectivity at a much earlier age:

Early adversity has profound and lasting effects on neurodevelopment and emotional behavior. Under typical environmental conditions, prefrontal cortex connections with the amygdala are immature during childhood and become adult-like during adolescence. Rodent models show that maternal deprivation accelerates this development as an ontogenetic adaptation to adversity. Here, we demonstrate that, as in the rodent, children who experienced early maternal deprivation exhibit early emergence of mature amygdala–prefrontal connectivity. Evidence suggests that the adult-like neural phenotype, which is mediated by cortisol levels, confers some degree of enhanced emotion regulation, as maternally deprived youths with adult-like phenotypes are less anxious than their counterparts with immature phenotypes. Accelerated amygdala–prefrontal development may serve as an ontogenetic adaptation in the human in response to early adversity. 

Francis Poulenc Sonata for piano 4 hands

Here is the last of the 4 hands pieces offered at a recent house concert/social at my Twin Valley Rd. home in Middleton,WI.

Threads of current debate: narcissism, ills of the world, scientism, brain science

I want to pass on some of the products of my TOC (tables of contents) scanning that I’m unlikely to develop into full posts, but that might be of interest to some readers.

Quenque does a piece focusing on San Diego State University psychologist Jean Twenge, who has compared decades of personality test results to conclude that younger generations are increasingly entitled, self-obsessed and unprepared for the realities of adult life. Critics have questioned her data and her results. A subsequent New York Times invitation for debate on social media and narcissism elicits a number of interesting views.

Novelist Janathan Franzen's extended screed in the Guardian on how the world is drifting towards disaster as we Tweet, Text, and spend has some choice passages, and draws a retort from Clive Thompson, who points out that similar hysteria has accompanied all new technology.

Steven Pinker's article in the New Republic,  "Science Is Not Your Enemy"  has drawn an avalanche of comment.  I've already mentioned one retort by Ross Douthat. Douthat follows this up with a piece on Sam Harris' offer of $20,000 for the best rebuttal of his book on how science can determine human values.  Leon Wieseltier rails against science invading the liberal arts.

In pieces more focused on brain science  Gopnik goes after mindless brain scientists, while Eric Kandel offers a rosy view of the new science of mind.  . 

Aspects of our musical experience.

I want to pass on three recent articles I found interesting. The first is a piece by Kawakami in the New York Times on why we like sad music, sumarizing his article in Frontiers in Psychology. He and his collaborators found that when listening to sad music

...felt emotion did not correspond exactly to perceived emotion. Although the sad music was both perceived and felt as “tragic” (e.g., gloomy, meditative and miserable), the listeners did not actually feel the tragic emotion as much as they perceived it. Likewise, when listening to sad music, the listeners felt more “romantic” emotion (e.g., fascinated, dear and in love) and “blithe” emotion (e.g., merry, animated and feel like dancing) than they perceived. (Glinka's "La Séparation" is one of the pieces used).

They suggest this may have something to do with vicarious emotions:

...when we listen to sad music (or watch a sad movie, or read a sad novel), we are inoculated from any real threat or danger that the music (or movie or novel) represents...If this is true, what we experience when we listen to sad music might be thought of as “vicarious emotions.” Here, there is no object or situation that induces emotion directly, as in regular life. Instead, the vicarious emotions are free from the essential unpleasantness of their genuine counterparts, while still drawing force from the similarity between the two.

The second article, by Leman et al., examines how music can entrain the speed of beat synchronized walking. Subjects walked to the rhythm of different musical pieces all having a tempo of 130 beats per minute and a meter of 4 beats. Some music was "activating" in that it increased stride length and distance covered, while "relaxing music" had the opposite effect. They suggest that recurrent patterns of fluctuation affecting the binary meter strength of the music may entrain the vigor of the movement, a relationship between entrainment and expressiveness that might lead to applications in sports and physical rehabilitation. Finally, Koelsch et al. do an intersting examination of processing of hierarchical syntactic structure in music:

Hierarchical structure with nested nonlocal dependencies is a key feature of human language and can be identified theoretically in most pieces of tonal music. However, previous studies have argued against the perception of such structures in music. Here, we show processing of nonlocal dependencies in music. We presented chorales by J. S. Bach and modified versions in which the hierarchical structure was rendered irregular whereas the local structure was kept intact. Brain electric responses differed between regular and irregular hierarchical structures, in both musicians and nonmusicians. This finding indicates that, when listening to music, humans apply cognitive processes that are capable of dealing with long-distance dependencies resulting from hierarchically organized syntactic structures. Our results reveal that a brain mechanism fundamental for syntactic processing is engaged during the perception of music, indicating that processing of hierarchical structure with nested nonlocal dependencies is not just a key component of human language, but a multidomain capacity of human cognition.

Theory of Mind and the mind of the market

The financial community has been in a striking tizzy over the fact that the Federal Reserve didn't do what they were predicting, i.e. start to dial back on their economic stimulus. The financial community also has not been very good at predicting or knowing when a financial bubble is growing. Perhaps work like this piece by Martino et al. casts some mechanistic light on this. They demonstrate that the ability to infer the intentions and mental states of other individuals (“theory of mind”) biases evaluation when people interact not with individuals but with complex modern institutions like financial markets, contributing to the formation of economics bubbles. Here is their summary:

The ability to infer intentions of other agents, called theory of mind (ToM), confers strong advantages for individuals in social situations. Here, we show that ToM can also be maladaptive when people interact with complex modern institutions like financial markets. We tested participants who were investing in an experimental bubble market, a situation in which the price of an asset is much higher than its underlying fundamental value. We describe a mechanism by which social signals computed in the dorsomedial prefrontal cortex affect value computations in ventromedial prefrontal cortex, thereby increasing an individual’s propensity to ‘ride’ financial bubbles and lose money. These regions compute a financial metric that signals variations in order flow intensity, prompting inference about other traders’ intentions. Our results suggest that incorporating inferences about the intentions of others when making value judgments in a complex financial market could lead to the formation of market bubbles.

Franz Schubert Marches caractéristiques, No. 2

This is second of the three four hands pieces played at a recent house concert at my Twin Valley Rd. home in Middleton, WI.

The joystick years - computer games and grey matter volume

Sian Lewis summarizes work by Kühn and Gallinat:

A new study has used voxel-based morphometry of MRI scans of adult video-game players to investigate whether there is a correlation between grey matter volume and the number of years spent playing video games ('joystick years'). They found that grey matter volume in the entorhinal cortex was altered and that the direction of change was influenced by the type of game played; logic or puzzle games tended to increase entorhinal grey matter volume, whereas action-based games had the opposite effect. Moreover, hippocampal volume was found to be greater in players with more 'joystick years', suggesting positive long-term effects on visual attention and navigation.

Clementi Sonata No. 2 in C for piano four hands

Here is the first of the four hands pieces performed at a concert at my home on Sept. 8.

Compassion - Bridging Practice and Science

Science magazine has an article by Kupferschmidt pointing to the work of Tania Singer, a director at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, who has embarked on an ambitious study involving 160 participants to find out whether meditation can make people more compassionate. He notes that meditation research does not have a very rigorous reputation, and some scientists are skeptical about the work, but Singer — who has long practiced meditation herself—hopes her study will be methodologically rigorous enough to withstand criticism. In 2004 Singer published a landmark paper in Science that showed that bilateral anterior insula (AI), rostral anterior cingulate cortex (ACC), brainstem, and cerebellum were activated when subjects received pain and also by a signal that a loved one experienced pain. AI and ACC activation correlated with individual empathy scores. Singer has just release a free 900-page e-book, entitled "Compassion - Bridging Practice and Science", that is quite amazing. I'm going to spend some time paging through it. Here is one clip from Kupferschmidt's commentary:

Numerous studies have shown that people can be "primed" to think more socially in various ways—from reading simple instructions to holding a warm cup of coffee. In one test, participants who listened to Bob Sinclar's hit song "Love Generation" were more likely to come up with words like "help" than those who listened to Sinclar's less uplifting song "Rock This Party." But Singer isn't interested in words; she wants to train people to act more socially in everyday life. And from personal experience, she believes meditation may be the way to do it. At its most basic, the technique simply involves focusing on a feeling. In one meditation exercise in her study, participants are told to imagine a person they love and to concentrate on positive feelings toward them. "May you be happy. May you be safe and sheltered. May you be healthy. May you live with a light heart," the teacher intones. Like bodybuilders increasing the weights they lift, meditators can intensify their compassionate feelings over time. Expert meditators can go very far, Singer says; rape victims may meditate on feeling compassion for their rapist, for instance. To measure meditation's effects, researchers in the ReSource Project determine the level of the stress hormone cortisol in participants' saliva, test their reaction times, have them fill out questionnaires, and shepherd them through virtual reality worlds while monitoring their heart rate. Each participant's brain is scanned for several hours five times over the course of the study. Participants also play computer games designed to evaluate their compassion level. In one of them, developed with Swiss economist Ernst Fehr, they have to guide a smiley along a winding path that leads to a treasure chest; they have blue or red keys to open gates of the same color. But another smiley is also wandering the screen, on its own quest to another treasure, and players have to decide whether to open gates for it, too. In a preliminary study in 2011, Singer showed that just one day of compassion meditation made people more likely to help the other smiley, whereas 1 day of memory training did not. Singer is also trying to better understand what goes on in the brain when it is feeling compassion. The activation patterns seen in the scanner leave open two possibilities: The feeling could be linked to the neurotransmitter dopamine and the brain's reward circuits (which, among many other things, makes you crave chocolate) or it could be linked to what she calls the affiliation network, which is activated for example when you view a picture of your partner or your own child, and is mediated by the neurotransmitters oxytocin or opioids. Singer admits that pinning down the neurobiology of compassion is difficult because the mental state it corresponds to remains fuzzy. A French Buddhist monk may have a very different concept of compassion than an African doctor or a British businessman, and there's friction between the classic third-person perspective of science and subjective experiences. "But we need the first-person experience as well as the third-person science," she says.

Poulenc Novelette No. 3

Here is the third of the Poulenc Novelettes, based on a theme by Manuel de Falla, a return to a more sonorous style, but with nice dissonances. It is one of the pieces played at a house concert Sept. 8, 2013, using the Steinway B at my Twin Valley Road home in Middleton, WI

Virtues of coffee and coffee shops.

I've been meaning to pass on these two articles that help me justify my addiction to breakfast and noon (but not dinner) coffee. Reynolds reviews a number of studies reporting at coffee consumption correlates with a 10% decrease in mortality over a 13 year period, reduced risk of developing type 2 diabetes and other diseases, and slower progression of dementia or Alzheimer's disease. O'Connor notes studies indicating that creative thinking is enhanced by ambient noise levels typical of a bustling coffee shop. The idea is that extreme quiet tends to sharpen focus, which can prevent thinking in the abstract. Moderate noise levels distract people enough so that they think more broadly. So, when you have been sitting at your keyboard for a long time and are beginning to feel a bit locked in, trying pulling up the coffitivity.com website, and see what it does for you.

Old farts perform more consistenly on cognitive tasks than younger adults.

Schmiedek et al. do a demonstration of something we more or less already knew...

People often attribute poor performance to having bad days. Given that cognitive aging leads to lower average levels of performance and more moment-to-moment variability, one might expect that older adults should show greater day-to-day variability and be more likely to experience bad days than younger adults. However, both researchers and ordinary people typically sample only one performance per day for a given activity. Hence, the empirical basis for concluding that cognitive performance does substantially vary from day to day is inadequate. On the basis of data from 101 younger and 103 older adults who completed nine cognitive tasks in 100 daily sessions, we show that the contributions of systematic day-to-day variability to overall observed variability are reliable but small. Thus, the impression of good versus bad days is largely due to performance fluctuations at faster timescales. Despite having lower average levels of performance, older adults showed more consistent levels of performance across days.

Poulenc Novelette No. 2 - a bit on the wild side

Poulenc's first two novelettes, the one in C major that I posted yesterday, and today's second novelette in B-flat minor, were composed in 1927 and 1928, and first performed by Poulenc at a Paris concert in June of 1928. The second novelette is in many ways similar to a scherzo, and very different from the sonorous and melodic first and third. All demonstrate multi-layered piano writing. Poulenc was mainly a self taught composer, and he was was one of the first openly gay composers, dedicating many of his pieces to his lovers. His most immediate influences were Chabrier, Debussy, Satie, and Stravinsky. Stravinsky helped get his early music published.

The cognitive benefits of movement reduction.

This piece by Warburton et al. shows another example of how musical, artistic, or athletic performance can be enhanced by subtle mimicking of the final full-out performance. I certainly use this technique in my piano playing. I notice many more possible refinements, errors, and nuances to tweak during either imagining play or playing very slowly and softly than in the normal more robust performance. Their abstract:

In a number of domains, humans adopt a strategy of systematically reducing and minimizing a codified system of movement. One particularly interesting case is “marking” in dance, wherein the dancer performs an attenuated version of the choreography during rehearsal. This is ostensibly to save the dancer’s physical energy, but a number of considerations suggest that it may serve a cognitive function as well. In this study, we tested this embodied-cognitive-load hypothesis by manipulating whether dancers rehearsed by marking or by dancing “full out” and found that performance was superior in the dancers who had marked. This finding indicates that marking confers cognitive benefits during the rehearsal process, and it raises questions regarding the cognitive functions of other movement-reduction systems, such as whispering, gesturing, and subvocalizing. In addition, it has implications for a variety of topics in cognitive science, including embodied cognition and the nascent fields of dance and music cognition.

Some mindblog music - Poulenc Novelette No. 1

Since the beginning of this blog, I've passed on classical piano recordings I make, and I'm going to do the same with some of the pieces performed at a house concert this past Sept 8 using the Steinway B at my Twin Valley Rd. home in Middleton, Wisconsin.

Video game training enhances cognitive control in older adults

This work has received a lot of attention (google 'NeuroRacer' to see various accounts), the video game is of the same sort as those mentioned in my Aug. 22 post. The abstract from Gazzaley and collaborators:

Cognitive control is defined by a set of neural processes that allow us to interact with our complex environment in a goal-directed manner. Humans regularly challenge these control processes when attempting to simultaneously accomplish multiple goals (multitasking), generating interference as the result of fundamental information processing limitations. It is clear that multitasking behaviour has become ubiquitous in today’s technologically dense world, and substantial evidence has accrued regarding multitasking difficulties and cognitive control deficits in our ageing population. Here we show that multitasking performance, as assessed with a custom-designed three-dimensional video game (NeuroRacer), exhibits a linear age-related decline from 20 to 79 years of age. By playing an adaptive version of NeuroRacer in multitasking training mode, older adults (60 to 85 years old) reduced multitasking costs compared to both an active control group and a no-contact control group, attaining levels beyond those achieved by untrained 20-year-old participants, with gains persisting for 6 months. Furthermore, age-related deficits in neural signatures of cognitive control, as measured with electroencephalography, were remediated by multitasking training (enhanced midline frontal theta power and frontal–posterior theta coherence). Critically, this training resulted in performance benefits that extended to untrained cognitive control abilities (enhanced sustained attention and working memory), with an increase in midline frontal theta power predicting the training-induced boost in sustained attention and preservation of multitasking improvement 6 months later. These findings highlight the robust plasticity of the prefrontal cognitive control system in the ageing brain, and provide the first evidence, to our knowledge, of how a custom-designed video game can be used to assess cognitive abilities across the lifespan, evaluate underlying neural mechanisms, and serve as a powerful tool for cognitive enhancement.

Political extremism is supported by an illusion of understanding.

Fernback et. al. start their interesting article with some nice quotes:

Bertrand Russell “The opinions that are held with passion are always those for which no good ground exists.”

Clint Eastwood “Extremism is so easy. You’ve got your position and that’s it. It doesn’t take much thought.”

Here is their abstract, followed by a bit on the experimental details:

People often hold extreme political attitudes about complex policies. We hypothesized that people typically know less about such policies than they think they do (the illusion of explanatory depth) and that polarized attitudes are enabled by simplistic causal models. Asking people to explain policies in detail both undermined the illusion of explanatory depth and led to attitudes that were more moderate (Experiments 1 and 2). Although these effects occurred when people were asked to generate a mechanistic explanation, they did not occur when people were instead asked to enumerate reasons for their policy preferences (Experiment 2). Finally, generating mechanistic explanations reduced donations to relevant political advocacy groups (Experiment 3). The evidence suggests that people’s mistaken sense that they understand the causal processes underlying policies contributes to political polarization.

Each of the experiments recruited 100-200 U.S. residents. In the first experiment, for example,

One hundred ninety-eight U.S. residents were recruited using Amazon’s Mechanical Turk and participated in return for a small payment. Participants were 52% male and 48% female, with an average age of 33.3 years. Participants’ reported political affiliations were 40% Democrat, 20% Republican, 36% independent, and 4% other.

In this study

...we asked participants to rate how well they understand six political policies. After participants judged their understanding of each issue, we asked them to explain how two of the policies work and then to rerate their level of understanding. We expected that asking participants to explain the mechanisms underlying the policies would expose the illusion of explanatory depth and lead to lower ratings of understanding….

This is the result obtained (motivated readers can obtain a PDF of the article with details from me).
The second study:

..was to examine whether the attitude-moderation effect observed in Experiment 1 was driven specifically by an attempt to explain mechanisms or merely by deeper engagement and consideration of the policies. To induce some participants to deliberate without explaining mechanisms, we asked one group to enumerate reasons why they held the policy attitude they did. Listing reasons why one supports or opposes a policy does not necessarily entail explaining how that policy works; for instance, a reason can appeal to a rule, a value, or a feeling…we predicted that asking people to list reasons for their attitudes would lead to less attitude moderation than would asking them to articulate mechanisms.

The third experiment

...examined whether the moderating effect of mechanistic explanations on political attitudes demonstrated in Experiments 1 and 2 would extend to political decisions. As in Experiment 2, participants first rated their position on a given policy and then provided either a mechanistic explanation of it or reasons why they supported or opposed it. Next, they chose whether or not to donate a bonus payment to a relevant advocacy group. We predicted that participants’ initial level of support for the policy would be more weakly associated with their subsequent likelihood of donating in the mechanism condition than in the reasons condition because articulating mechanisms attenuates attitude extremity more than does listing reasons.

A pinch of l-dopa enhances learning to suppress excessive fear responses.

Haaker et al. make an interesting observation:

Traumatic events can engender persistent excessive fear responses to trauma reminders that may return even after successful treatment. In the psychotherapy of fear or anxiety disorders, patients make safety experiences that generate fear-inhibitory safety memories. Fear, however, frequently returns because safety memory retrieval fails. We find that safety memories can be strengthened and are more easily retrieved when adding a standard anti-Parkinson drug that augments brain levels of the neurotransmitter dopamine directly after a safety experience. In mice and humans, this treatment up-regulates an anti-fear area in the frontal cortex. Our findings open a unique avenue for improving psychotherapy.

Numerosity is represented in our parietal cortex.

Our primary sensory cortices are arranged topographically, and Harvey et al. have now tested the speculation that numerosity is also organized topographically by using ultrahigh-field functional brain scanning to demonstrate a numerosity map in the parietal cortex:

Numerosity, the set size of a group of items, is processed by the association cortex, but certain aspects mirror the properties of primary senses. Sensory cortices contain topographic maps reflecting the structure of sensory organs. Are the cortical representation and processing of numerosity organized topographically, even though no sensory organ has a numerical structure? Using high-field functional magnetic resonance imaging (at a field strength of 7 teslas), we described neural populations tuned to small numerosities in the human parietal cortex. They are organized topographically, forming a numerosity map that is robust to changes in low-level stimulus features. The cortical surface area devoted to specific numerosities decreases with increasing numerosity, and the tuning width increases with preferred numerosity. These organizational properties extend topographic principles to the representation of higher-order abstract features in the association cortex.

Scientific explanation of our subjective experience.....

Being a card carrying materialist, I've always felt that our mental life could be explained in physical terms. Although I consider myself a twinkie when it comes to appreciating deep philosophical debate, I really think Nagel's succinct summary of the main argument in his recent book "Mind and Cosmos" doesn't hold water, because it makes a basic category error that Metzinger has pointed out. More on that below, but first some clips of Nagel's summary, and a subsequent refutation by Kitcher.

The physical sciences can describe organisms like ourselves as parts of the objective spatio-temporal order – our structure and behavior in space and time – but they cannot describe the subjective experiences of such organisms or how the world appears to their different particular points of view. There can be a purely physical description of the neurophysiological processes that give rise to an experience, and also of the physical behavior that is typically associated with it, but such a description, however complete, will leave out the subjective essence of the experience – how it is from the point of view of its subject — without which it would not be a conscious experience at all.

So the physical sciences, in spite of their extraordinary success in their own domain, necessarily leave an important aspect of nature unexplained.  Further, since the mental arises through the development of animal organisms, the nature of those organisms cannot be fully understood through the physical sciences alone.  Finally, since the long process of biological evolution is responsible for the existence of conscious organisms, and since a purely physical process cannot explain their existence, it follows that biological evolution must be more than just a physical process, and the theory of evolution, if it is to explain the existence of conscious life, must become more than just a physical theory.

Kitcher argues:

...Once he has set up the framework within which the possible positions will be placed, his arguments are not easy to resist. In my view, though, the framework itself is faulty.

Contrary to the Newtonian vision in which everything would be explained on the basis of a small number of physical principles:

…since the 19th century — since Darwin, in fact — that has not been a convincing picture of how the sciences make their advances. Darwin did not supply a major set of new principles that could be used to derive general conclusions about life and its history: he crafted a framework within which his successors construct models of quite specific evolutionary phenomena. Model-building lies at the heart of large parts of the sciences, including parts of physics. There are no grand theories, but lots of bits and pieces, generating local insights about phenomena of special interest….The molecular biologist doesn’t account for life, but for a particular function of life (usually in a particular strain of a particular species). Nagel’s 19th-century predecessors wondered how life could be characterized in physico-chemical terms. That particular wonder hasn’t been directly addressed by the extraordinary biological accomplishments of past decades. Rather, it’s been shown that they were posing the wrong question: don’t ask what life is (in your deepest Newtonian voice); consider the various activities in which living organisms engage and try to give a piecemeal understanding of those.

First, philosophy and science don’t always answer the questions they pose — sometimes they get over them. Second, instead of asking what life and mind and value are, think about what living things and minds do, and what is going on in the human practices of valuing. This shift of perspective has already occurred in the case of life. A Nagel analog who worried about the fact that we lack a physico-chemical account of life, would probably be rudely dismissed; a kinder approach would be to talk about the ways in which various aspects of living things have been illuminated.

Nagel is in the grip of a philosophical perspective on science, once very popular, that the work of the last four decades has shown to be inadequate to cope with large parts of the most successful contemporary sciences. Because of that perspective, a crucial option disappears from his menu: the phenomena that concern him, mind and value, are not illusory, but it might nevertheless be an illusion that they constitute single topics for which unified explanations can be given. The probable future of science in these domains is one of decomposition and the provision of an enormous and heterogeneous family of models. Much later in the day, it may fall to some neuroscientist to explain the illusion of unity, a last twist on successful accounts of many subspecies of mental processes and functions. Or, perhaps, it will be clear by then that the supposed unity of mind and of value were outgrowths of a philosophical mistake, understandable in the context of a particular stage of scientific development, but an error nonetheless.

I think the most coherent view of what is going on in our subjective mental experience is given by Thomas Metzinger in his book "The Ego Tunnel"….. I've extracted some points:

- What he calls the Ego Tunnel (or PSM) is a complex property of the global neural correlate of consciousness (NCC which are the subject of many books)  - what make “Mineness” or “I” possible - a vastly reduced model of what is really 'out there.'

 

- It is a transparent mental image that allows the conscious experience of being a self  to emerge. (Transparency is our not seeing the firing of neurons in our brain, only what they represent for us).

 

- The model at a given moment is transparent because the brain has no chance of discovering that is is a model - it is a higher order representation integrating its information in longer time window than the lower order information processing in smaller time windows. 

 

- Our visual perception time window is much larger than the time windows of primary visual processing and so those more rapid underlying processes are completely invisible to it (the same thing as not being able to see the individual frames in a movie reel,  because our visual integration time is much longer).   It is a metabolically efficient, quick and dirty way of knowing only what our evolution has deemed it necessary for us to know. 

   

-In this view, Consciousness is taken to be the space of attentional agency,  that set of information currently active in our brains to which we can deliberately direct our high level attention.  Low level attention is automatic and can be triggered by entirely unconscious events.  

 

- Metzinger makes the further assertion that consciousness is epistemologically irreducible:   one reality, one kind of fact, but two kinds of knowledge: first-person knowledge and third-person knowledge, that never can be conflated.

 

- There is a long list of ideas on why consciousness evolved, what it is good for, doing goal hierarchies and long-terms plans, enhancement of social coordination, etc....Old things in the evolution of consciousness are ultrafast and reliable (like qualities of sensory experience) and transparent. In contrast, abstract conscious thought is not transparent or fast,  it is slow and unreliable, experienced as ‘made.’

I like Metzinger's description of consciousness as a  as a new kind of virtual organ - unlike the permanent hardware of the liver, kidney, or heart it is always present. Virtual organs form for a certain time when needed (like an immune response, or like desire, courage, anger)...they are a new computational strategy, that makes classes of facts globally available and allows attending, flexible reacting, within context. The fast acting hardware of our autonomic and neuroendocrine emotional chemistry evolved to support the new classes of transient virtual organs.

Language can boost unseen objects into visual awareness.

From Lupyan et al:

Linguistic labels (e.g., “chair”) seem to activate visual properties of the objects to which they refer. Here we investigated whether language-based activation of visual representations can affect the ability to simply detect the presence of an object. We used continuous flash suppression to suppress visual awareness of familiar objects while they were continuously presented to one eye. Participants made simple detection decisions, indicating whether they saw any image. Hearing a verbal label before the simple detection task changed performance relative to an uninformative cue baseline. Valid labels improved performance relative to no-label baseline trials. Invalid labels decreased performance. Labels affected both sensitivity (d′) and response times. In addition, we found that the effectiveness of labels varied predictably as a function of the match between the shape of the stimulus and the shape denoted by the label. Together, the findings suggest that facilitated detection of invisible objects due to language occurs at a perceptual rather than semantic locus. We hypothesize that when information associated with verbal labels matches stimulus-driven activity, language can provide a boost to perception, propelling an otherwise invisible image into awareness.

A Methods note:

Continuous flash suppression was implemented using anaglyph images: participants wore red/cyan glasses and viewed stereograms containing a high-contrast red mask (∼9° × 9°) and—on object-present trials—a superimposed lower-contrast cyan object (Fig. 1A). Only the object was visible to the right eye and only the mask to the left. The dynamic mask comprised curved line segments, with frames randomly alternating at 10 Hz. Because similarity in spatial properties between stimuli and masks is important for effective suppression of stimuli (72), line segments were used to better mask the curvilinear character of the objects.

(A) Stimulus creation using continuous flash suppression. (B) Basic procedure of experiments 1 and 2.

A drug that alters dopamine receptors and risk-taking behaviors

Interesting observations from Norbury et al. on a drug that activates or enhances action of some dopamine receptors and also increases the probability of taking risky choices. (Maybe a receptor antagonist should be developed for hedge fund managers and investment bankers who keep crashing our economy!).

Trait sensation-seeking, defined as a need for varied, complex, and intense sensations, represents a relatively underexplored hedonic drive in human behavioral neuroscience research. It is related to increased risk for a range of behaviors including substance use, gambling, and risky sexual practice. Individual differences in self-reported sensation-seeking have been linked to brain dopamine function, particularly at D2-like receptors, but so far no causal evidence exists for a role of dopamine in sensation-seeking behavior in humans. Here, we investigated the effects of the selective D2/D3 agonist cabergoline on performance of a probabilistic risky choice task in healthy humans using a sensitive within-subject, placebo-controlled design. Cabergoline significantly influenced the way participants combined different explicit signals regarding probability and loss when choosing between response options associated with uncertain outcomes. Importantly, these effects were strongly dependent on baseline sensation-seeking score. Overall, cabergoline increased sensitivity of choice to information about probability of winning; while decreasing discrimination according to magnitude of potential losses associated with different options. The largest effects of the drug were observed in participants with lower sensation-seeking scores. These findings provide evidence that risk-taking behavior in humans can be directly manipulated by a dopaminergic drug, but that the effectiveness of such a manipulation depends on baseline differences in sensation-seeking trait. This emphasizes the importance of considering individual differences when investigating manipulation of risky decision-making, and may have relevance for the development of pharmacotherapies for disorders involving excessive risk-taking in humans, such as pathological gambling.

Nighttime light impairs our emotional responses.

I have done a number of posts (enter melanopsin in the search box to find them) on a second visual system, involving the visual pigment melanopsin in our retinal ganglion cells, that has been shown to influence mood,memory, and cognition. Bedrosian et al. now add more detail to this story, showing that noctural light exposure, particularly to blue light, impairs emotional responses:

Life on earth is entrained to a 24 h solar cycle that synchronizes circadian rhythms in physiology and behavior; light is the most potent entraining cue. In mammals, light is detected by (1) rods and cones, which mediate visual function, and (2) intrinsically photosensitive retinal ganglion cells (ipRGCs), which primarily project to the suprachiasmatic nucleus (SCN) in the hypothalamus to regulate circadian rhythms. Recent evidence, however, demonstrates that ipRGCs also project to limbic brain regions, suggesting that, through this pathway, light may have a role in cognition and mood. Therefore, it follows that unnatural exposure to light may have negative consequences for mood or behavior. Modern environmental lighting conditions have led to excessive exposure to light at night (LAN), and particularly to blue wavelength lights. We hypothesized that nocturnal light exposure (i.e., dim LAN) would induce depressive responses and alter neuronal structure in hamsters (Phodopus sungorus). If this effect is mediated by ipRGCs, which have reduced sensitivity to red wavelength light, then we predicted that red LAN would have limited effects on brain and behavior compared with shorter wavelengths. Additionally, red LAN would not induce c-Fos activation in the SCN. Our results demonstrate that exposure to LAN influences behavior and neuronal plasticity and that this effect is likely mediated by ipRGCs. Modern sources of LAN that contain blue wavelengths may be particularly disruptive to the circadian system, potentially contributing to altered mood regulation.

Better safe than sorry?...Anxiety and our body’s safety margin.

Sambo and Iannetti find interesting correlations between our anxiety and our interpersonal space boundaries:

The defensive peripersonal space represents a “safety margin” advantageous for survival. Its spatial extension and the possible relationship with personality traits have never been investigated. Here, in a population of 15 healthy human participants, we show that the defensive peripersonal space has a sharp boundary, located between 20 and 40 cm from the face, and that within such space there is a thin, “highest-risk area” closest to the face (i.e., an “ultra-near” defensive space). Single-subject analysis revealed clear interindividual differences in the extension of such peripersonal space. These differences are positively related to individual variability in trait anxiety. These findings point to the potential for measuring a range of defensive behaviors in relation to individual levels of anxiety. Such measures will allow developing procedures to test risk assessment abilities, particularly in professions that require reacting quickly to aversive stimuli near the body, such as firemen, policemen, and military officers. This may also lead to possible interventions to improve their performance under pressure.

Dopamine, rewards, and the brain

The neurotransmitter dopamine is one we all seem to have heard about, claimed to be central to love, gambling, reward, addiction, etc. A recent article by Howe et al. shows a bit more nuance than previously assumed in what dopamine levels are signaling. They ramp up during navigation towards an expected reward. I thought I would pass on a clip from Niv's summary of their findings, followed by the Howe et al. abstract

a, Dopaminergic neurons in the midbrain project to all brain areas, most prominently to the striatum (black arrows). These cells fire at a constant rate of 3–5 spikes per second, with occasional phasic bursts or pauses on the occurrence of positive reward prediction errors (discovering that the local supermarket now supplies your favourite coffee beans, b) or negative reward prediction errors (sipping your coffee and finding that the milk has gone sour, c), respectively. The background (tonic) level of dopamine fluctuates slowly, possibly tracking the average rate of rewards (not shown). d, By measuring dopamine concentrations in the striatum of rats navigating mazes, Howe et al.1 reveal a third mode of dopaminergic signalling: when a prolonged series of actions must be completed to obtain a reward (for instance, all the steps it takes to make a cup of coffee), dopamine concentration ramps up gradually, at each point in time signalling the predicted distance from the goal.

The abstract:

Predictions about future rewarding events have a powerful influence on behaviour. The phasic spike activity of dopamine-containing neurons, and corresponding dopamine transients in the striatum, are thought to underlie these predictions, encoding positive and negative reward prediction errors. However, many behaviours are directed towards distant goals, for which transient signals may fail to provide sustained drive. Here we report an extended mode of reward-predictive dopamine signalling in the striatum that emerged as rats moved towards distant goals. These dopamine signals, which were detected with fast-scan cyclic voltammetry (FSCV), gradually increased or—in rare instances—decreased as the animals navigated mazes to reach remote rewards, rather than having phasic or steady tonic profiles. These dopamine increases (ramps) scaled flexibly with both the distance and size of the rewards. During learning, these dopamine signals showed spatial preferences for goals in different locations and readily changed in magnitude to reflect changing values of the distant rewards. Such prolonged dopamine signalling could provide sustained motivational drive, a control mechanism that may be important for normal behaviour and that can be impaired in a range of neurologic and neuropsychiatric disorders.

Interesting…thinking about science enhances moral behavior.

There have been a number of high profile cases of dishonesty in reporting scientific results over the past ten years, but these errors in the conduct of the scientific method may not change public attitude towards scientific method itself. Ma-Kellams and Blascovich, using the usual cohort of university undergraduates as subjects (this time at Univ. of California Santa Barbara) show that exposure to science and experimental primes of science increase the likelihood of enforcing moral norms, Thinking about science had a moralizing effect on several domains: interpersonal violations, prosocial intentions, and economic exploitation. The experiments tested whether inducing thoughts about science could influence both reported, as well as actual, moral behavior by "priming" students with expose words like “logical,” “hypothesis,” “laboratory” and “theory.” They then judged the severity of a date-rape transgression, determined the level of altruistic activities they intended over the next month, and did a behavioral economic game that measures the level of altruistic motivation. The author's conclusions:

These studies demonstrated the morally normative effects of lay notions of science. Thinking about science leads individuals to endorse more stringent moral norms and exhibit more morally normative behavior. These studies are the first of their kind to systematically and empirically test the relationship between science and morality. The present findings speak to this question and elucidate the value-laden outcomes of the notion of science.

The social pathologies generated by connectivity and internet echo-chambers.

I have to pass on two zinger's from today's paper, a nice piece by Bruni, written during a Shanghai stay, on the ease of keeping your personal world cocoon intact through your iPad and ignoring the real world around you. And second, an article by Bilton on how many moments of our lives we are not really present because we are looking at a smartphone. Brief clips:

...Every experience is being mediated and conceived around how it can be captured and augmented by our devices...No place is this more apparent than our meals, where every portion leading up to, during and after a dining experience is being carved out by particular apps...People make dinner reservations on OpenTable; check in on Foursquare when they arrive at the restaurant; take a picture of their food to share on Instagram; post on Twitter a joke they hear during the meal; review the restaurant on Yelp; then, finally, coordinate a ride home using Uber.

The article also points to a sobering video that has gone viral (18 million viewing as I write this). I have embedded it here:



Maybe the situation isn't hopeless, because the iPhone is only really six years old, and Bilton cites a hopeful precedent:

In the late 1950s, televisions started to move into the kitchen from the living room, often wheeled up to the dinner table to join the family for supper. And then, TV at the dinner table suddenly became bad manners. Back to the living room the TV went.

Second language training reorganizes right hemisphere areas.

Hosoda et al. do a clear demonstration of how first and second languages mainly recruit different part of the brain. Training in a second language correlates with enlargement of parts of the right hemisphere, not the innately favored left hemisphere language areas used by the first language.

It remains unsettled whether human language relies exclusively on innately privileged brain structure in the left hemisphere or is more flexibly shaped through experiences, which induce neuroplastic changes in potentially relevant neural circuits. Here we show that learning of second language (L2) vocabulary and its cessation can induce bidirectional changes in the mirror-reverse of the traditional language areas. A cross-sectional study identified that gray matter volume in the inferior frontal gyrus pars opercularis (IFGop) and connectivity of the IFGop with the caudate nucleus and the superior temporal gyrus/supramarginal (STG/SMG), predominantly in the right hemisphere, were positively correlated with L2 vocabulary competence. We then implemented a cohort study involving 16 weeks of L2 training in university students. Brain structure before training did not predict the later gain in L2 ability. However, training intervention did increase IFGop volume and reorganization of white matter including the IFGop-caudate and IFGop-STG/SMG pathways in the right hemisphere. These “positive” plastic changes were correlated with the gain in L2 ability in the trained group but were not observed in the control group. We propose that the right hemispheric network can be reorganized into language-related areas through use-dependent plasticity in young adults, reflecting a repertoire of flexible reorganization of the neural substrates responding to linguistic experiences.