Saturday, March 28, 2020

Springtime for introverts...

Thank goodness some sparks of humor are available to lighten the somber clouds of the COVID-19 pandemic. You should check out Atlantic staff writer Andrew Ferguson’ piece in that magazine as well as New Yorker cartoonist Chris Ware’s “Self-Isolating: A Pandemic Special"...Thirty years of avoiding other human beings...validated! Here are a few clips from Ferguson:
That February was the virus’s American debut is fitting, because many introverts were still recovering from the trauma of the end-of-year holidays...We are the people...who preferred to eat alone at corner tables in restaurants with a book propped up on the salt shaker, ignoring the occasional puzzled or pitying glances from the extroverts at the bar. Replace the restaurant corner table with a tub of takeout, eaten over the sink standing up, and you can see how everyone else’s new normal conforms to our old normal. I have never known an introvert who washed his or her hands fewer than a dozen times a day; it’s our version of calisthenics. Hugs, long a source of terror for us, are now generally understood to be as violent and unwelcome as decapitation. The elbow bump is a social greeting most introverts can live with, far superior anyway to the viral autobahn of the handshake. A brief, awkward wave at six paces would be best of all. Indeed, for a true introvert, any encounter closer than six feet constitutes foreplay.
Only recently has introversion been deemed a social force, thanks to the writer Susan Cain. She became an unofficial spokesperson, a very soft-spoken spokesperson, when she published Quiet: The Power of Introverts in a World That Can’t Stop Talking a few years ago...Her book became a huge best seller with the aid of the internet, which allowed its target audience to buy as many copies as they wished without having to go to the store...Her theme was perhaps novel to some people, but not to us: This is the extroverts’ world; the introverts just live in it...If Cain’s book, readable, clever, and popular as it is, was intended as a revolutionary manifesto, it largely failed. It is very difficult to coordinate an uprising of people who would rather not leave the house. Now, though, the virus has done what a revolution never could: The social order has been upended, and extroverts find themselves living in the introverts’ world.
Consider: As Cain points out, the world’s most introverted country, Finland, is also the world’s happiest.
How introverted are the Finns? Here’s how: You can tell a Finn likes you if he’s looking at your shoes instead of his own.
That’s a joke the Finns tell on themselves! Just because people are introverted doesn’t mean we can’t have a little fun. We just don’t want to overdo it, is all.

Friday, March 27, 2020

When we return to the gym...A molecular muscle memory helps retraining of muscles after inactivity.

For me the most deranging part of the current "Stay Home" order that I am obeying during the coronavirus crisis is being unable to do my customary workouts at a gym. It is heartening to see Gretchen Reynolds point to a study that finds that...
...if muscles have been trained in the past, they seem to develop a molecular memory of working out that lingers through a prolonged period of inactivity, and once we start training again, this “muscle memory” can speed the process by which we regain our former muscular strength and size.
Swedish researchers...began by recruiting 19 young men and women who had never played sports or formally exercised at all, so that their muscles were new to formal weight training. They checked these volunteers’ current muscular strength and size, and then had them start training a single leg...one-legged workouts continued for 10 weeks, at which point the researchers re-measured muscles, and then the volunteers stopped their training completely for 20 weeks...After this layoff from working out, they returned to the lab, where the scientists checked the current state of their leg muscles, took muscle biopsies from both legs and had them complete a strenuous leg workout, using both legs this time. Afterward, the researchers biopsied the muscles again. Then they checked the levels of a wide array of gene markers and biochemical signals within the volunteers’ muscle cells that are believed to be related to muscle health and growth.
They found telling differences between the legs that had trained and those that had not, both before and after the lone training session. For one thing, the previously trained leg remained sturdier, having retained about 50 percent of its strength gains during the 20 weeks without exercise.
Taken as a whole..the trained leg’s genetic activity suggests that its muscle cells had become genetically and metabolically more ready to strengthen and grow than the cells in the leg that had not trained before. These findings support the idea that muscle memory can occur at the gene and protein level.

Thursday, March 26, 2020

The world after coronavirus.

I want to point to an article in the Financial Times by Yuval Harari that makes a clear description of choices the current pandemic is forcing on us. You should read the whole piece, but here are a few clips:
In this time of crisis, we face two particularly important choices. The first is between totalitarian surveillance and citizen empowerment. The second is between nationalist isolation and global solidarity.
In order to stop the epidemic, entire populations need to comply with certain guidelines. There are two main ways of achieving this. One method is for the government to monitor people, and punish those who break the rules. Today, for the first time in human history, technology makes it possible to monitor everyone all the time...governments have already deployed the new surveillance tools. The most notable case is China. By closely monitoring people’s smartphones, making use of hundreds of millions of face-recognising cameras, and obliging people to check and report their body temperature and medical condition, the Chinese authorities can not only quickly identify suspected coronavirus carriers, but also track their movements and identify anyone they came into contact with. A range of mobile apps warn citizens about their proximity to infected patients...This kind of technology is not limited to east Asia. Prime Minister Benjamin Netanyahu of Israel recently authorised the Israel Security Agency to deploy surveillance technology normally reserved for battling terrorists to track coronavirus patients.
Asking people to choose between privacy and health is, in fact, the very root of the problem. Because this is a false choice. We can and should enjoy both privacy and health. We can choose to protect our health and stop the coronavirus epidemic not by instituting totalitarian surveillance regimes, but rather by empowering citizens. In recent weeks, some of the most successful efforts to contain the coronavirus epidemic were orchestrated by South Korea, Taiwan and Singapore. While these countries have made some use of tracking applications, they have relied far more on extensive testing, on honest reporting, and on the willing co-operation of a well-informed public.
The coronavirus epidemic is thus a major test of citizenship. In the days ahead, each one of us should choose to trust scientific data and healthcare experts over unfounded conspiracy theories and self-serving politicians. If we fail to make the right choice, we might find ourselves signing away our most precious freedoms, thinking that this is the only way to safeguard our health.
The second important choice we confront is between nationalist isolation and global solidarity. Both the epidemic itself and the resulting economic crisis are global problems. They can be solved effectively only by global co-operation...A collective paralysis has gripped the international community. There seem to be no adults in the room. One would have expected to see already weeks ago an emergency meeting of global leaders to come up with a common plan of action. The G7 leaders managed to organise a videoconference only this week, and it did not result in any such plan....In previous global crises — such as the 2008 financial crisis and the 2014 Ebola epidemic — the US assumed the role of global leader. But the current US administration has abdicated the job of leader. It has made it very clear that it cares about the greatness of America far more than about the future of humanity.
Humanity needs to make a choice. Will we travel down the route of disunity, or will we adopt the path of global solidarity? If we choose disunity, this will not only prolong the crisis, but will probably result in even worse catastrophes in the future. If we choose global solidarity, it will be a victory not only against the coronavirus, but against all future epidemics and crises that might assail humankind in the 21st century.

Wednesday, March 25, 2020

Modeling Donald Trump - A Process Model of Narcissistic Status Pursuit

From Grapsas et al.:
We propose a self-regulation model of grandiose narcissism. This model illustrates an interconnected set of processes through which narcissists (i.e., individuals with relatively high levels of grandiose narcissism) pursue social status in their moment-by-moment transactions with their environments. The model shows that narcissists select situations that afford status. Narcissists vigilantly attend to cues related to the status they and others have in these situations and, on the basis of these perceived cues, appraise whether they can elevate their status or reduce the status of others. Narcissists engage in self-promotion (admiration pathway) or other-derogation (rivalry pathway) in accordance with these appraisals. Each pathway has unique consequences for how narcissists are perceived by others, thus shaping their social status over time. The model demonstrates how narcissism manifests itself as a stable and consistent cluster of behaviors in pursuit of social status and how it develops and maintains itself over time. More broadly, the model might offer useful insights for future process models of other personality traits.

Monday, March 23, 2020

A Psychological Profile of the Alt-Right

From Forscher and Kteily:
The 2016 U.S. presidential election coincided with the rise of the “alternative right,” or alt-right. Alt-right associates have wielded considerable influence on the current administration and on social discourse, but the movement’s loose organizational structure has led to disparate portrayals of its members’ psychology and made it difficult to decipher its aims and reach. To systematically explore the alt-right’s psychology, we recruited two U.S. samples: An exploratory sample through Amazon’s Mechanical Turk (N = 827, alt-right n = 447) and a larger, nationally representative sample through the National Opinion Research Center’s Amerispeak panel (N = 1,283, alt-right n = 71–160, depending on the definition). We estimate that 6% of the U.S. population and 10% of Trump voters identify as alt-right. Alt-right adherents reported a psychological profile more reflective of the desire for group-based dominance than economic anxiety. Although both the alt-right and non-alt-right Trump voters differed substantially from non-alt-right, non-Trump voters, the alt-right and Trump voters were quite similar, differing mainly in the alt-right’s especially high enthusiasm for Trump, suspicion of mainstream media, trust in alternative media, and desire for collective action on behalf of Whites. We argue for renewed consideration of overt forms of bias in contemporary intergroup research.

Friday, March 20, 2020

Surprise! Oil and gas companies give more money to legislators that vote against the environment.

Goldberg et al. analyze campaign contribution data over 28 years to show that, rather than attempting to influence votes, interested parties contribute the most to legislators that have policy positions that are already aligned with the interested party.
Do campaign contributions from oil and gas companies influence legislators to vote against the environment, or do these companies invest in legislators that have a proven antienvironmental voting record? Using 28 y of campaign contribution data, we find that evidence consistently supports the investment hypothesis: The more a given member of Congress votes against environmental policies, the more contributions they receive from oil and gas companies supporting their reelection.

Wednesday, March 18, 2020

Humans were not designed for sitting in chairs.

As I near my 78th birthday I've become increasingly aware of how debilitating activities like sitting and typing this blog post can be. Moving just a bit is a relief (as when I crank my desktop up to standing level or move about just a bit) and exposes how the body's fluxes can become shut down on sitting. This makes me want to pass on the original abstract for work described by Reynolds on how modern hunter-gatherer people deal with periods of being sedentary.  From Raichlen et al.:  

Significance
Inactivity is a growing public health risk in industrialized societies, leading some to suggest that our bodies did not evolve to be sedentary. Here, we show that, in a group of hunter-gatherers, time spent sedentary is similar to that found in industrialized populations. However, sedentary time in hunter-gatherers is often spent in postures like squatting that lead to higher levels of muscle activity than chair sitting. Thus, we suggest human physiology likely evolved in a context that included substantial inactivity, but increased muscle activity during sedentary time, suggesting an inactivity mismatch with the more common chair-sitting postures found in contemporary urban populations.
Abstract
Recent work suggests human physiology is not well adapted to prolonged periods of inactivity, with time spent sitting increasing cardiovascular disease and mortality risk. Health risks from sitting are generally linked with reduced levels of muscle contractions in chair-sitting postures and associated reductions in muscle metabolism. These inactivity-associated health risks are somewhat paradoxical, since evolutionary pressures tend to favor energy-minimizing strategies, including rest. Here, we examined inactivity in a hunter-gatherer population (the Hadza of Tanzania) to understand how sedentary behaviors occur in a nonindustrial economic context more typical of humans’ evolutionary history. We tested the hypothesis that nonambulatory rest in hunter-gatherers involves increased muscle activity that is different from chair-sitting sedentary postures used in industrialized populations. Using a combination of objectively measured inactivity from thigh-worn accelerometers, observational data, and electromygraphic data, we show that hunter-gatherers have high levels of total nonambulatory time (mean ± SD = 9.90 ± 2.36 h/d), similar to those found in industrialized populations. However, nonambulatory time in Hadza adults often occurs in postures like squatting, and we show that these “active rest” postures require higher levels of lower limb muscle activity than chair sitting. Based on our results, we introduce the Inactivity Mismatch Hypothesis and propose that human physiology is likely adapted to more consistently active muscles derived from both physical activity and from nonambulatory postures with higher levels of muscle contraction. Interventions built on this model may help reduce the negative health impacts of inactivity in industrialized populations.

Monday, March 16, 2020

Krugman on Piketty's new book on inequality - "Capital and Ideology'

Krugman's review is worth reading in it entirely, and I pass on a few clips that encapsulate his summary and option of Piketty's core points. Piketty:
...describes four broad inequality regimes, obviously inspired by French history but, he argues, of more general relevance. First are “ternary” societies divided into functional classes — clergy, nobility and everyone else. Second are “ownership” societies, in which it’s not who you are that matters but what you have legal title to. Then come the social democracies that emerged in the 20th century, which granted considerable power and privilege to workers, ranging from union representation to government-provided social benefits. Finally, there’s the current era of “hypercapitalism,” which is sort of an ownership society on steroids.
For Piketty, rising inequality is at root a political phenomenon. The social-democratic framework that made Western societies relatively equal for a couple of generations after World War II, he argues, was dismantled, not out of necessity, but because of the rise of a “neo-proprietarian” ideology. Indeed, this is a view shared by many, though not all, economists. These days, attributing inequality mainly to the ineluctable forces of technology and globalization is out of fashion, and there is much more emphasis on factors like the decline of unions, which has a lot to do with political decisions.
But why did policy take a hard-right turn? Piketty places much of the blame on center-left parties, which, as he notes, increasingly represent highly educated voters. These more and more elitist parties, he argues, lost interest in policies that helped the disadvantaged, and hence forfeited their support. And his clear implication is that social democracy can be revived by refocusing on populist economic policies, and winning back the working class.
Piketty could be right about this, but as far as I can tell, most political scientists would disagree. In the United States, at least, they stress the importance of race and social issues in driving the white working class away from Democrats, and doubt that a renewed focus on equality would bring those voters back. After all, during the Obama years the Affordable Care Act extended health insurance to many disadvantaged voters, while tax rates on top incomes went up substantially. Yet the white working class went heavily for Trump, and stayed Republican in 2018.

Friday, March 13, 2020

MindBlog passes on a note: on the relief of not being yourself.

I am going to start occasionally doing MindBlog posts on ideas that I think might have the potential of developing into longer pieces of work, but that usually remain as notes in my personal journal. This first one follows in the thread of Monday’s post on the work of Sam Harris. It came together when I woke during the middle of the night to find my mind clogged with a traffic jam of discursive thought. Then what appeared in my mind, in what felt like a mini-epiphany, was the words that I pass on below. They may make little sense to many readers, but please be assured that I have not gone wacko or nutter....
What a relief to know that this is not me, it is just the contents of my consciousness, which shift around all the time and are never the same twice. What has changed, after 45 years of doing an introspective personal journal, is that this sentence has become clear and true for me. It is a prying loose from the illusion of the sensing and executive “I”, self, the homunculus inside.
There is a particular feeling of renewal, starting over, in the first moments of the transition to seeing - rather than immersed in being - one of the contents of consciousness. Meditation practice can be seen as training the ability to inhabit this state for longer periods of time, to experience the self or I as co-equal with other contents of consciousness like seeing, hearing, feeling. It is having thoughts without a thinker, having a self without a self.
What is inside is the animal mirror of expanded consciousness, no longer locked into one or another of its contractions. This feels to me like a potentially irreversible quantum bump, a phase or state change in my ongoing awareness (perhaps a long term increase in my brain’s attentional mode activity alongside a decrease its default mode’s mind wandering?...also frontal suppression of amygdalar reactivity?)
(I would add the note, as I did to Monday's post, that experiences of the sort I describe here can be very disorienting to some people, and should be approached with caution. A google search for the names Willoughby Britton and Jarred Lindahl will take you to their papers on this issue.)

Wednesday, March 11, 2020

Cannabis increases susceptibility to false memory.

From Kloft et al.:  

Significance
This unique randomized, double-blind, placebo-controlled trial examined the susceptibility to false memories under the influence of cannabis, using a basic (DRM) and two applied (misinformation) paradigms. We used a highly powered experimental design, allowing us to test acute and residual drug effects. To achieve high reproducibility and ecological validity, the misinformation paradigms included an eyewitness and a perpetrator scenario, presented in a virtual-reality environment. We show across different paradigms that cannabis consistently increases susceptibility to false memories. The results have implications for police, legal professionals, and policymakers with regard to the treatment of cannabis-intoxicated witnesses and suspects and the validity of their statements.
Abstract
With the growing global acceptance of cannabis and its widespread use by eyewitnesses and suspects in legal cases, understanding the popular drug’s ramifications for memory is a pressing need. In a double-blind, randomized, placebo-controlled trial, we examined the acute and delayed effects of Δ9-tetrahydrocannabinol (THC) intoxication on susceptibility to false memory in 64 healthy volunteers. Memory was tested immediately (encoding and retrieval under drug influence) and 1 wk later (retrieval sober). We used three different methods (associative word lists and two misinformation tasks using virtual reality). Across all methods, we found evidence for enhanced false-memory effects in intoxicated participants. Specifically, intoxicated participants showed higher false recognition in the associative word-list task both at immediate and delayed test than controls. This yes bias became increasingly strong with decreasing levels of association between studied and test items. In a misinformation task, intoxicated participants were more susceptible to false-memory creation using a virtual-reality eyewitness scenario and virtual-reality perpetrator scenario. False-memory effects were mostly restricted to the acute-intoxication phase. Cannabis seems to increase false-memory proneness, with decreasing strength of association between an event and a test item, as assessed by different false-memory paradigms. Our findings have implications for how and when the police should interview suspects and eyewitnesses.

Monday, March 09, 2020

Sam Harris' "Waking Up" wakes up Deric's MindBlog

Over the past few months I have gone back to school by doing the entire sequence of lectures and exercises presented by two mindfulness meditation apps. The first of these these, the HealthyMinds App, I have mentioned in a previous post. It derives from a collaborative effort at the Center for Healthy Minds at the University of Wisconsin, headed by my former colleague Richard Davidson. It is a friendly, approachable, lite version of material covered with greater intellectual depth by the second App, Waking Up, which is done by author Sam Harris and based on his book titled "Waking Up - A Guide to Spirituality Without Religion." I became much more immersed in Harris' program, finishing all of the mini-lectures or 'lessons' and the 50 guided 10 minute exercises. Harris' presentation was a catalyst for me, allowing the material I have been writing about since my 2002 I-Illusion web/lecture to actually gel into place as lived daily experience.

Below I pass on an idiosyncratic sampling of clips or paraphrases of material from Harris' exercises, lectures, and book. For some readers there might be a flash of recognition, for others the following might make no sense at all.
The pronoun I is the name that most of us put to the sense that we are the thinkers of our thoughts and the experiencers of our experience. It is the sense that we have of possessing (rather than of merely being) a continuum of experience...this feeling is not a necessary property of the mind...the experience of being a self can be selectively interfered with...people can report losing their sense of self to one or another degree
...the present centered expanded awareness that is seeing or feeling fear, anger suffering or pain  is not fear, anger suffering or pain. The same is true for happiness, joy, contentment. It is not these things but the calm presence that surrounds them. 
What do you take yourself to be in this moment? Is it the sensation of your face? Or your head?  Resolve that these too are appearances in consciousness, consciousness is prior to them, a mere witness of them.  Fall back into that position, being the screen on which the movie of your life is being played...This introduces a new capacity to respond differently to experiences. To notice first what it is you are experiencing, and then to introduce an option beyond merely reacting, being captured by the next thought that rises in consciousness.
...rest as that condition in which everything is just appearing...Feel the energy of your body, notice how sounds appear and disappear.  And let your mind be like a mirror. It doesn’t move to reflect what is in it. Everything simply appears on its surface... Now, periodically, gently, don’t make a struggle, look for the one who is noticing. And in that first moment of turning, see if you can observe what noticing is like. What is hearing like in the first instance of looking for the one who is hearing? What is sensing of breath like if you look for the seat of attention?
..There is no state that you are producing that by definition excludes any other experience. A goal is to make features of consciousness obvious, so that they can be obvious in other moments of your life.Your mind is always with you, practice develops a range of insights into what it’s like before it becomes cluttered by concepts, and judgements, and reactions, and other contractions in consciousness.
Kindle a negative feeling, bore into it with your attention, feel it as closely as possible, its energy. This kind of attention robs it of meaning.  It is simply an appearance in consciousness at this moment. How could this arising in feeling be what you are? You are simply noticing it. And it passes away on its own...the half life of any negative mental space is remarkably short.  And just noticing that, apart from any insight you might have into the nature of consciousness, can be freeing.  
It’s almost like you’re watching a film, and consciousness is both the screen and the light projected, the entire substance of experience. The sense that there is a self, a seat of attention, a subject in the middle of experience, that is yet another appearance on the screen, that’s part of the movie. That is part of what is being experienced and what may yet be witnessed from the point of view of open awareness. 
...consciousness is different. It appears to have no form at all, because anything that would give it form must arise within the field of consciousness. Consciousness is simply the light by which the contours of mind and body are known. It is that which is aware of feelings such as joy, regret, amusement, and despair. It can seem to take their shape for a time, but it is possible to recognize that it never quite does. Once one recognizes the selflessness of consciousness, the practice of meditation becomes just a means of getting more familiar with it. The goal, thereafter, is to cease to overlook what is already the case.…we can directly experience that consciousness is never improved or harmed by what it knows. Making this discovery, again and again, is the basis of spiritual life.
Everything we take ourselves to be at the level of our subjectivity—our memories and emotions, our capacity for language, the very thoughts and impulses that give rise to our behavior—depends upon distinct processes that are spread out over the whole of the brain. Many of these can be independently interrupted or extinguished. The sense, therefore, that we are unified subjects—the unchanging thinkers of thoughts and experiencers of experience—is an illusion. The conventional self is a transitory appearance among transitory appearances, and it vanishes when looked for. We need not await any data from the lab to say that self-transcendence is possible. And we need not become masters of meditation to realize its benefits. It is within our capacity to recognize the nature of thoughts, to awaken from the dream of being merely ourselves and, in this way, to become better able to contribute to the well-being of others.
Harris notes a motivation for his writing on spirituality and self transcendence:
Spirituality remains the great hole in secularism, humanism, rationalism, atheism, and all the other defensive postures that reasonable men and women strike in the presence of unreasonable faith. People on both sides of this divide imagine that visionary experience has no place within the context of science—apart from the corridors of a mental hospital. Until we can talk about spirituality in rational terms—acknowledging the validity of self-transcendence—our world will remain shattered by dogmatism. This book has been my attempt to begin such a conversation.
  (I should mention that a few users of the Waking Up App have found the exercises to be disorienting and stressful, and the App contains a fascinating two hour discussion between Harris and Willoughby Britton and Jarred Lindahl, who have done research on 'The Dark Side of Meditation.' A google search on their names will take you to their publications on this issue.)

Friday, March 06, 2020

Using your brain's functional connectivity to track psychiatric symptoms and treatments.

Sylvester et al. propose examining the functional connectivity of the amygdala as a substrate for precision psychiatry. Their work provides a detailed framework of amygdala–cortical interactions that can be used as a foundation for models relating aberrations in amygdala connectivity to psychiatric symptoms in individual patients.  

Significance
Disrupted functional connectivity of the amygdala may be central to mental illness. Yet, little is known about the functional connectivity of the amygdala in individuals, limiting our ability to understand and treat amygdala dysconnectivity in individual patients. Here, we divide the amygdala into three subdivisions in each of 10 individuals and define connectivity patterns using 5 h of fMRI data per person. We demonstrate that, across individuals, each of the three amygdala subdivisions occupies a roughly consistent location and exhibits consistent functional connectivity with specific cortical functional networks: One to the default mode network, another to the dorsal attention network, and a third without preferential connectivity.
Abstract
The amygdala is central to the pathophysiology of many psychiatric illnesses. An imprecise understanding of how the amygdala fits into the larger network organization of the human brain, however, limits our ability to create models of dysfunction in individual patients to guide personalized treatment. Therefore, we investigated the position of the amygdala and its functional subdivisions within the network organization of the brain in 10 highly sampled individuals (5 h of fMRI data per person). We characterized three functional subdivisions within the amygdala of each individual. We discovered that one subdivision is preferentially correlated with the default mode network; a second is preferentially correlated with the dorsal attention and fronto-parietal networks; and third subdivision does not have any networks to which it is preferentially correlated relative to the other two subdivisions. All three subdivisions are positively correlated with ventral attention and somatomotor networks and negatively correlated with salience and cingulo-opercular networks. These observations were replicated in an independent group dataset of 120 individuals. We also found substantial across-subject variation in the distribution and magnitude of amygdala functional connectivity with the cerebral cortex that related to individual differences in the stereotactic locations both of amygdala subdivisions and of cortical functional brain networks. Finally, using lag analyses, we found consistent temporal ordering of fMRI signals in the cortex relative to amygdala subdivisions. Altogether, this work provides a detailed framework of amygdala–cortical interactions that can be used as a foundation for models relating aberrations in amygdala connectivity to psychiatric symptoms in individual patients.

Wednesday, March 04, 2020

Why are teenagers so unpredictable and impulsive? - brain changes during adolescence

Why do teenagers frequently behave so unpredictably and impulsively? Perhaps because their brains are undergoing disruptive changes in connectivity between cortical and subcortical areas that collaborate to regulate more advanced behaviors such as such as socializing, mentalizing, and executive skills. From Váša et al.:  

Significance
How does the human brain change during adolescence? We found 2 distinct modes of change in functional connectivity between brain regions, “conservative” and “disruptive,” measured using functional MRI (fMRI) in healthy young people (14 to 26 y old). Conservative regions, often specialized for basic sensory and motor functions, were strongly connected at age 14 before strengthening more by age 26, whereas disruptive regions that were activated by complex tasks comprised both connections that were weak at age 14 but strengthened by age 26 and connections that were strong at age 14 but weakened by age 26. Disruptive maturation of fMRI connectivity between cortex and subcortex could represent metabolically costly remodeling that underpins development of adult faculties.
Abstract
Adolescent changes in human brain function are not entirely understood. Here, we used multiecho functional MRI (fMRI) to measure developmental change in functional connectivity (FC) of resting-state oscillations between pairs of 330 cortical regions and 16 subcortical regions in 298 healthy adolescents scanned 520 times. Participants were aged 14 to 26 y and were scanned on 1 to 3 occasions at least 6 mo apart. We found 2 distinct modes of age-related change in FC: “conservative” and “disruptive.” Conservative development was characteristic of primary cortex, which was strongly connected at 14 y and became even more connected in the period from 14 to 26 y. Disruptive development was characteristic of association cortex and subcortical regions, where connectivity was remodeled: connections that were weak at 14 y became stronger during adolescence, and connections that were strong at 14 y became weaker. These modes of development were quantified using the maturational index (MI), estimated as Spearman’s correlation between edgewise baseline FC (at 14 y, FC14 ) and adolescent change in FC (ΔFC14−26), at each region. Disruptive systems (with negative MI) were activated by social cognition and autobiographical memory tasks in prior fMRI data and significantly colocated with prior maps of aerobic glycolysis (AG), AG-related gene expression, postnatal cortical surface expansion, and adolescent shrinkage of cortical thickness. The presence of these 2 modes of development was robust to numerous sensitivity analyses. We conclude that human brain organization is disrupted during adolescence by remodeling of FC between association cortical and subcortical areas.

Monday, March 02, 2020

Speech versus music in the brain

Peter Stern summarizes work of Albouy et al. in the current issue of Science Magazine:
To what extent does the perception of speech and music depend on different mechanisms in the human brain? What is the anatomical basis underlying this specialization? Albouy et al. created a corpus of a cappella songs that contain both speech (semantic) and music (melodic) information and degraded each stimulus selectively in either the temporal or spectral domain. Degradation of temporal information impaired speech recognition but not melody recognition, whereas degradation of spectral information impaired melody recognition but not speech recognition. Brain scanning revealed a right-left asymmetry for speech and music. Classification of speech content occurred exclusively in the left auditory cortex, whereas classification of melodic content occurred only in the right auditory cortex.
And here is the Albouy et al. abstract:
Does brain asymmetry for speech and music emerge from acoustical cues or from domain-specific neural networks? We selectively filtered temporal or spectral modulations in sung speech stimuli for which verbal and melodic content was crossed and balanced. Perception of speech decreased only with degradation of temporal information, whereas perception of melodies decreased only with spectral degradation. Functional magnetic resonance imaging data showed that the neural decoding of speech and melodies depends on activity patterns in left and right auditory regions, respectively. This asymmetry is supported by specific sensitivity to spectrotemporal modulation rates within each region. Finally, the effects of degradation on perception were paralleled by their effects on neural classification. Our results suggest a match between acoustical properties of communicative signals and neural specializations adapted to that purpose.