Friday, December 30, 2016

Resetting the clock of aging - at least in mice.

I pass on a few clips from Nicholas Wade's recent discussion of work done by researchers at the Salk Institute in La Jolla, CA.
In the first attempt to reverse aging by reprogramming the genome, they have rejuvenated the organs of mice and lengthened their life spans by 30 percent. The technique, which requires genetic engineering, cannot be applied directly to people, but the achievement points toward better understanding of human aging and the possibility of rejuvenating human tissues by other means.
The aging process is clocklike in the sense that a steady accumulation of changes eventually degrades the efficiency of the body’s cells. In one of the deepest mysteries of biology, the clock’s hands are always set back to zero at conception...Ten years ago, the Japanese biologist Shinya Yamanaka amazed researchers by identifying four critical genes that reset the clock of the fertilized egg. The four genes are so powerful that they will reprogram even the genome of skin or intestinal cells back to the embryonic state.
The Salk Inst. researchers, using whole animals, tested the idea:
...that reprogramming is a stepwise process, and that a small dose of the Yamanaka factors might rejuvenate cells without the total reprogramming that converts cells to the embryonic state...The solution his team developed was to genetically engineer mice with extra copies of the four Yamanaka genes, and to have the genes activated only when the mice received a certain drug in their drinking water, applied just two days a week...“What we saw is that the animal has fewer signs of aging, healthier organs, and at the end of the experiment we could see they had lived 30 percent longer than control mice,” Dr. Izpisua Belmonte said.
Dr. Izpisua Belmonte believes these beneficial effects have been obtained by resetting the clock of the aging process. The clock is created by the epigenome, the system of proteins that clads the cell’s DNA and controls which genes are active and which are suppressed...He sees the epigenome as being like a manuscript that is continually edited. “At the end of life there are many marks and it is difficult for the cell to read them,” he said...What the Yamanaka genes are doing in his mice, he believes, is eliminating the extra marks, thus reverting the cell to a more youthful state.
Dr. Izpisua Belmonte said he was testing drugs to see if he could achieve the same rejuvenation as with the Yamanaka factors. The use of chemicals “will be more translatable to human therapies and clinical applications.”

Thursday, December 29, 2016

Killing old cells to stay young.

I want to pass on one of Science Magazine's choices for the top ten scientific breakthroughs of the year.
Pricey plastic surgery won't stop you from getting old. Nor will dietary supplements, testosterone injections, or those wrinkle creams that imply they'll make you look 21 again. But this year, researchers demonstrated one way to postpone some ravages of time—at least in mice. When they selectively weeded out rundown cells, the animals lived longer and remained healthier as they aged.
The infirm cells the scientists targeted had undergone a partial shutdown known as senescence, in which they lose the ability to divide. Researchers think senescence may prevent worn-out, cancer-prone cells from initiating tumors, but it may also promote aging. As we grow older, more and more cells stop reproducing, potentially robbing our tissues of the ability to replace dead or injured cells. Senescent cells also discharge molecules that can cause problems such as abnormal cell growth and inflammation.
The first study showing that eliminating senescent cells can produce health and longevity benefits, at least in middle-aged mice, came out in February. Deterioration of the animals' hearts and kidneys slowed, and they didn't sprout tumors until later in their lives. Some age-related declines, such as in memory and muscle coordination, didn't abate. Nonetheless, the rodents outlived their contemporaries by more than 20%.
In October, the same research team took aim at senescent cells from the immune system that amass in artery-clogging plaques and may drive their formation. Removing these cells from mice that are prone to atherosclerosis reduced the amount of fatty buildup in the animals' arteries by 60%, even though the rodents gorged on fat-laden food.
The multibillion-dollar question: Will taking out senescent cells help humans stay young longer? Both studies used genetically modified mice that clear away their senescent cells in response to a particular compound—a technique that isn't feasible in humans. But researchers have created several so-called senolytic drugs that slay senescent cells without genetic tinkering. Next year, scientists will launch the first clinical trial of one of those drugs in people who have arthritis.
D. J. Baker et al., “Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders,” Nature 479, 232 (2 November 2016)
D. J. Baker et al., “Naturally occurring p16Ink4a-positive cells shorten healthy lifespan,,” Nature 530, 184 (11 February 2016)
B. G. Childs et al., “Senescent intimal foam cells are deleterious at all stages of atherosclerosis,” News from Science 354, 472 (28 October 2016)

Wednesday, December 28, 2016

Creative versus destructive chaos in Trump-land. Is there a ray of hope?

I am a member of the professional intelligentsia bubble still feeling post-traumatic stress from the presidential election. I grasp at any small reassurances that the sky may not in fact be falling, and so point to this piece by David Ignatius noting the current influence of Robert Gates, who has worked in senior national security positions for the past five presidents. Some clips:
At the top of Gates’s to-do list is striking the right balance between improving relations with Russia and appearing too cooperative with a belligerent President Vladimir Putin...“I think the challenge for any new administration would have been how to thread the needle — between stopping the downward spiral in U.S.-Russian relations, which had real dangers, and pushing back on Putin’s aggressiveness and general thuggery,” Gates said.
Gates has shared the role of informal counselor to the Trump transition team with two other veterans of the Bush administration, former secretary of state Condoleezza Rice, who talks regularly with Vice President-elect Mike Pence, and former national security adviser Stephen Hadley. The three have a consulting firm, RiceHadleyGates, which has proposed candidates for Cabinet and sub-Cabinet jobs, including Rex Tillerson and retired Marine Gen. James N. Mattis, the choices for State and Defense, respectively.
Gates, Hadley and Rice have also talked with foreign governments that are puzzled about how to approach Trump. In an interview this week, Hadley summarized his basic advice:..“We’ve never had a populist movement or political insurgency quite like this — that actually captured the White House. That means there will be more discontinuities in our foreign policy. I’m telling people: ‘Give us some space here and have some strategic patience. And don’t overreact — even to Trump’s tweets.’ ”
One issue that worries Gates is the multiplicity of people surrounding Trump in the White House, seeking to influence an undisciplined chief executive. “What happens when someone tries to get in to see the president with a proposal or initiative and is rebuffed by one gatekeeper — and simply goes through another door? It’s a formula for a disjointed process.”
“There will be a rough break-in period,” Gates predicted. Part of the challenge is that Trump believes his success stems from his freewheeling, undisciplined style, and personal messaging through Twitter — which makes him resist limits.

Tuesday, December 27, 2016

Artificial intelligence ups its game

I pass on this description by John Bohannon in Science Magazine of a recent triumph of A.I.:
This year, artificial intelligence (AI) passed a significant milestone when a computer program called AlphaGo beat the world's No. 2 Go player in a five-game match. It's not the first time that AI has surpassed human mastery of a game. After all, it was 20 years ago that IBM's Deep Blue first beat Garry Kasparov in a game of chess, toppling the world champion the following year in a six-game match. But that is where the similarity ends.
The rules of Go are more straightforward than those of chess: You simply place identical stones on a grid, capturing territory by surrounding your opponent's positions. But that simplicity and openness result in an explosion in the number of possible moves for a player to consider—far more than there are atoms in the known universe. That makes it impossible for AI to beat Go masters with an approach like that used by Deep Blue, which relies on handcoded strategies from chess experts to evaluate each possible move.
Instead, AlphaGo, designed by the London-based Google subsidiary DeepMind, studied hundreds of thousands of online Go games played between humans, using those sequences of moves as data for a machine-learning algorithm. Then AlphaGo played against itself—or, rather, slightly different versions of itself—over and over, finetuning its strategies with a technique called deep reinforcement learning. The final result is AI that wins not just with brute-force calculation, but with something that looks strikingly like human intuition.
Most of the things we want AI to master involve a seemingly unmanageable number of possible decisions—walking a robot safely through a crowded room, routing driverless cars, making small talk with passengers. Because hard-coded rules fail for such tasks, AlphaGo's triumph shows just how powerful deep reinforcement learning can be.
D. Mackenzie, “Update: Why this week’s man-versus-Go match doesn’t matter (and what does,” News from Science (15 March 2016)
D. Silver, “Mastering the game of Go with deep neural networks and tree search,” Nature 589, 224 (28 January 2016)

Monday, December 26, 2016

Making the world nicer is a tough slog - two organizations trying.

The end of 2016 approaches, I am thinking about charitable donations I have made or might make in this angry and uncertain time of huge political changes. Angry voters in Europe and America are turning back the clock, and the paradigm of America may be irreversibly changing. A collective trauma is being generated by the severing of ties that previously have bound Americans together. How might we try to be more kind, gentle, and understanding with each other?

I've decided to make year end contributions to two university associated organizations trying to promote the greater good through research, teaching, and understanding - trying to find ways to spread and promote the virtues of altruism, compassion, gratitude, empathy, forgiveness, and mindfulness. One is the Greater Good Science Center at the University of California, Berkeley, founded by Dacher Keltner. The other is the Center for Healthy Minds at the University of Wisconsin, Madison, led by my former colleague Richard Davidson. I would encourage MindBlog readers to check out their websites, and consider donations to both.

Friday, December 23, 2016

Our automated jobless future.

Elizabeth Kolbert offers an interesting review of ideas in several recent books dealing with our automated future. How long will it be before you lose your job to a robot? Here are a few clips:
Imagine a matrix with two axes, manual versus cognitive and routine versus nonroutine. Jobs can then be arranged into four boxes: manual routine, manual nonroutine, and so on…Jobs on an assembly line fall into the manual-routine box, jobs in home health care into the manual-nonroutine box. Keeping track of inventory is in the cognitive-routine box; dreaming up an ad campaign is cognitive nonroutine.
The highest-paid jobs are clustered in the last box; managing a hedge fund, litigating a bankruptcy, and producing a TV show are all cognitive and nonroutine. Manual, nonroutine jobs, meanwhile, tend to be among the lowest paid—emptying bedpans, bussing tables, cleaning hotel rooms (and folding towels). Routine jobs on the factory floor or in payroll or accounting departments tend to fall in between. And it’s these middle-class jobs that robots have the easiest time laying their grippers on.
How much technology has contributed to the widening income gap in the U.S. is a matter of debate; some economists treat it as just one factor, others treat it as the determining factor. In either case, the trend line is ominous. Facebook is worth two hundred and seventy billion dollars and employs just thirteen thousand people. In 2014, Facebook acquired Whatsapp for twenty-two billion dollars. At that point, the messaging firm had a grand total of fifty-five employees. When a twenty-two-billion-dollar company can fit its entire workforce into a Greyhound bus, the concept of surplus labor would seem to have run its course.
Martin Ford (author of “Rise of the Robots: Technology and the Threat of a Jobless Future”) worries that we are headed toward an era of “techno-feudalism,” He imagines a plutocracy shut away “in gated communities or in elite cities, perhaps guarded by autonomous military robots and drones.” Under the old feudalism, the peasants were exploited; under the new arrangement, they’ll merely be superfluous. The best we can hope for, he suggests, is a collective form of semi-retirement. He recommends a guaranteed basic income for all, to be paid for with new taxes, levelled, at least in part, on the new gazillionaires.
To one degree or another, just about everyone writing on the topic shares this view. Jerry Kaplan proposes that the federal government create a 401(k)-like account for every ten-year-old in the U.S. Those who ultimately do find jobs could contribute some of their earnings to the accounts; those who don’t could perform volunteer work in return for government contributions.
...if it’s unrealistic to suppose that smart machines can be stopped, it’s probably just as unrealistic to imagine that smart policies will follow. Which brings us ... to Trump. The other day, during his “victory lap” through the Midwest, the President-elect vowed to “usher in a new Industrial Revolution,” apparently unaware that such a revolution is already under way, and that this is precisely the problem. The pain of dislocation he spoke to during the campaign is genuine; the solutions he offers are not.

Thursday, December 22, 2016

A stark graphic - the income gap continues to widen.

The NYTimes piece by Patricia Cohen and graphic summaries by Ashkenas are worth reading. The top 1% and the bottom 50% have swapped their relative shares of the national income. Forty years ago, the top 1 percent of earners took home 10.5 percent of the total national income, and the bottom half earned 20 percent of it. By 2014, those percentages effectively flipped, with the top 1 percent earning a 20 percent share and the bottom half dropping to 12.5 percent.

Wednesday, December 21, 2016

Our Arthropod housemates.

Now I know more about what is in the haze of particles I see illuminated by the horizontal rays of the rising sun flowing through my Fort Lauderdale condo in early morning.  I pass on, under the "random curious stuff" MindBlog category,  an accounting by Madden et al. that shows the ubiquity of insects detected in settled dust samples collected from inside homes. They used a DNA-based method for investigating the arthropod diversity in homes via high-throughput marker gene sequencing of home dust. Settled dust samples were collected by citizen scientists from both inside and outside more than 700 homes across the United States, yielding the first continental-scale estimates of arthropod diversity associated with our residences. Here is a graphic (click to enlarge), in which (A) shows the Genera detected, (B) shows orders detected in at least 5% of homes. The Y-axes indicate the percentage of homes (of 651 homes with arthropods detected) where those arthropods were detected.

Tuesday, December 20, 2016

Reducing future fears by suppressing episodic simulation in the brain.

Benoit et al. offer some findings relevant to understanding the heightened anxiety many are feeling in the Age of Trump.

An edited summary that starts the discussion section of their paper:
Recurrently imagining dreaded future situations potentiates fears and can even support the development and maintenance of anxiety disorders. We tested the hypothesis that such simulations can be suppressed with the opposite effect of down-regulating apprehensiveness. Our data indicate that future suppression is based on a brain mechanism that is remarkably similar to a system implicated in the voluntary suppression of past experiences. This mechanism recruits right dorsolateral prefrontal cortex, which originates an inhibitory signal that down-regulates activation in brain regions supporting both retrieval and episode-construction processes. Paralleling the suppression of recently acquired memories, the regions targeted by future suppression included the hippocampus, a structure that is fundamental for the retrieval of past episodes and the construction of coherent future and fictitious events. Critically, the suppression of recurring fears of the future differs from suppressing past events in that it also involved modulating the vmPFC (ventromedial prefrontal cortex). The mPFC fosters the integration of overlapping memories into a common representation.
A clip describing their procedure:
To examine future suppression, we adapted the “Think/No-Think” procedure, used to study the suppression of past events, to create the new “Imagine/No-Imagine” paradigm. The procedure first asked participants to describe their fears. Importantly, they only provided recurrent future fears—that is, those that they had already worried might happen before entering the experiment. Participants then gave one key detail for each fear that was typical to their recurring imaginings of it. (These typical event details served as a dependent measure; see below.) Afterward, they entered the critical Imagine/No-Imagine phase, which was composed of trials that presented reminders to these fears. For some trials, participants were asked to imagine the feared event as vividly as possible in response to the reminder (Imagine condition); for others, participants were asked to suppress their imagining of the event, upon seeing the reminder (Suppress condition). (A third of the originally provided episodes, the Baseline items, were set aside and were not cued during this phase.) Over the course of the Imagine/No-Imagine phase, participants either imagined or suppressed a feared event 12 times. Following this phase, we gave participants each reminder again and asked them to recall the typical feature of its corresponding fear. Once all typical details were tested, participants were then asked to freely imagine each episode aloud in detail for 2 min. Finally, we assessed the impact of suppression on participants’ apprehensiveness toward these future events.
Here are the significance and abstract section of their paper:
Humans possess the remarkable ability to recombine details of divergent memories into imaginings of future events. Such imaginings are useful, for example, because they foster planning and motivate farsighted decisions. Importantly, recurrently imagining feared situations can also undermine our well-being and may even contribute to the development of anxiety. Here, we demonstrate that fearful imaginings about the future can be inhibited by neural mechanisms that help to suppress the past. Importantly, suppression reduces later apprehensiveness about the feared events, a benefit that was diminished in individuals with greater trait anxiety. This pattern suggests that the observed inhibition mechanism serves to control people’s future fears and its disruption may foster psychological disorders characterized by intrusive prospective thoughts. 
Imagining future events conveys adaptive benefits, yet recurrent simulations of feared situations may help to maintain anxiety. In two studies, we tested the hypothesis that people can attenuate future fears by suppressing anticipatory simulations of dreaded events. Participants repeatedly imagined upsetting episodes that they feared might happen to them and suppressed imaginings of other such events. Suppressing imagination engaged the right dorsolateral prefrontal cortex, which modulated activation in the hippocampus and in the ventromedial prefrontal cortex (vmPFC). Consistent with the role of the vmPFC in providing access to details that are typical for an event, stronger inhibition of this region was associated with greater forgetting of such details. Suppression further hindered participants’ ability to later freely envision suppressed episodes. Critically, it also reduced feelings of apprehensiveness about the feared scenario, and individuals who were particularly successful at down-regulating fears were also less trait-anxious. Attenuating apprehensiveness by suppressing simulations of feared events may thus be an effective coping strategy, suggesting that a deficiency in this mechanism could contribute to the development of anxiety.

Monday, December 19, 2016

Can evolution have a 'higher purpose'?

I want to point to this essay by Robert Wright, author of "The Moral Animal," who makes the point that arguments that life on earth may have some larger purpose do not necessarily have to depart from a scientific worldview, invoke supernatural beings, or depart from the model of evolution by natural selection. Among these arguments are:
... “simulation” scenarios, which hold that our seemingly tangible world is actually a kind of projection emanating from some sort of mind-blowingly powerful computer; and the history of our universe, including evolution on this planet, is the unfolding of a computer algorithm...When an argument for higher purpose is put this way — that is, when it doesn’t involve the phrase “higher purpose” and, further, is cast more as a technological scenario than a metaphysical one — it is considered intellectually respectable. I don’t mean there aren’t plenty of people who dismiss it. I’m talking about how people dismiss it. [Neil deGrasse Tyson and Elon Musk find this view plausible.]
Wright quotes from a conversation with William Hamilton, who says:
There’s one theory of the universe that I rather like — I accept it in an almost joking spirit — and that is that Planet Earth in our solar system is a kind of zoo for extraterrestrial beings who dwell out there somewhere. And this is the best, the most interesting experiment they could set up: to set up the evolution on Planet Earth going in such a way that it would produce these really interesting characters — humans who go around doing things — and they watch their experiment, interfering hardly at all so that almost everything we do comes out according to the laws of nature. But every now and then they see something which doesn’t look quite right — this zoo is going to kill itself off if they let you do this or that.” So, he continued, these extraterrestrials “insert a finger and just change some little thing. And maybe those are the miracles which the religious people like to so emphasize.” He reiterated: “I put it forward in an almost joking spirit. But I think it
Another scenario:
...emerges from one version of physicist Lee Smolin’s theory of “cosmological natural selection.” Smolin thinks our universe may itself be a product of a kind of evolution: maybe universes can replicate themselves via black holes, so over time — over a lot of time — you get universes whose physical laws are more and more conducive to replication. (So that’s why our universe is so good at black-hole making!) In some variants of Smolin’s theory — such as those developed by the late cosmologist Edward Harrison and the mathematician Louis Crane — intelligent beings can play a role in this replication once their technology reaches a point where they can produce black holes. So through cosmological natural selection you’d get universes whose physical properties were more and more conducive to the evolution of intelligent life. This might explain the much-discussed observation that the physical constants of this universe seem “fine-tuned” to permit the emergence of life.
Wilson's ending points:
I think discussion of higher purpose should be respectable even in a scientific age. I don’t mean I buy the simulation scenario in particular, or the space alien scenario, or the cosmological natural selection scenario. But I do think there’s reason to suspect that there’s some point to this exercise we Earthlings are engaged in, some purpose imbued by something — and that, even if identifying that something is for now hopeless, there are grounds for speculating about what the point of the exercise is.
I won’t elaborate much on this, since I’ve done that elsewhere, arguing that higher purpose can be framed as a hypothesis, and that evidence for or against the hypothesis can be marshaled. But I will say that the evidence I see for purpose includes not just the direction of biological evolution, but the direction of technological evolution and of the broader social and cultural evolution it drives — the evolution that has carried us from hunter-gatherer bands to the brink of a cohesive global community. And if the purpose involves sustaining this direction — becoming a true global community — then it would seem to include moral progress. In particular, our purpose would involve transcending the psychology of tribalism that can otherwise divide people along ethnic, national, religious and ideological lines. Which would mean — in light of recent political and social developments in the United States and abroad — that our work is cut out for us.

Friday, December 16, 2016

Political tribes, and the psychology of liberals and conservatives.

I am using this post to pass on to MindBlog readers some background material I just sent out to members of a senior current topics discussion group that we have recently formed in Fort Lauderdale, and named "The Round Table." The session on Monday Dec. 19 is on the topic indicated by the title of this post.

Where do tribes come from? Evolutionary origins   

What is essential human nature? Where do religion and morality come from?  How do  religious and non-religious people differ?  

What dynamics regulate in-group and out-group interactions and conflicts?  brain correlates of whether we help someone suffering

What kinds of political tribes do people belong to today?

What distinguishes liberals and conservatives?

How do people sustain their tribal identities, what psychological shortcuts or errors help?

How can tribal animosities and conflicts be ameliorated?

Thursday, December 15, 2016

Bad things that happen to annoyingly happy people...

There is abundant evidence that being or appearing to be happy confers lots of advantages in life, both in personal health, relationships and in the workplace. On the down side, however, Ana Swanson points to work by Barasch et al. showing that very happy people are more likely to get ripped off:

• We examine how the magnitude of expressed happiness influences social perception. 
• Very happy people are perceived as more naïve than moderately happy individuals. 
• Very happy people are believed to shelter themselves from negative information. 
• Very happy people are exploited in conflicts of interest and distributive negotiations. 
• We challenge prior work by identifying a disadvantage of expressing happiness.
Across six studies, we examine how the magnitude of expressed happiness influences social perception and interpersonal behavior. We find that happiness evokes different judgments when expressed at high levels than when expressed at moderate levels, and that these judgments influence opportunistic behavior. Specifically, people perceive very happy individuals to be more naïve than moderately happy individuals. These perceptions reflect the belief that very happy individuals shelter themselves from negative information about the world. As a result of these inferences, very happy people, relative to moderately happy people, are more likely to receive biased advice from advisors with a conflict of interest and are more likely to be chosen as negotiation partners when the opportunity for exploitation is salient. Our findings challenge existing assumptions in organizational behavior and psychology by identifying a significant disadvantage of expressing happiness, and underscore the importance of examining emotional expressions at different magnitudes. We call for future work to explore how the same emotion, experienced or expressed at different levels, influences judgment and behavior.

Wednesday, December 14, 2016

Why does time fly when you’re having fun? Dopamine neurons…

Soares et al. find by observing timing behavior in mice that dopaminergic neurons control temporal judgments on a time scale of seconds.
Our sense of time is far from constant. For instance, time flies when we are having fun, and it slows to a trickle when we are bored. Midbrain dopamine neurons have been implicated in variable time estimation. However, a direct link between signals carried by dopamine neurons and temporal judgments is lacking. We measured and manipulated the activity of dopamine neurons as mice judged the duration of time intervals. We found that pharmacogenetic suppression of dopamine neurons decreased behavioral sensitivity to time and that dopamine neurons encoded information about trial-to-trial variability in time estimates. Last, we found that transient activation or inhibition of dopamine neurons was sufficient to slow down or speed up time estimation, respectively. Dopamine neuron activity thus reflects and can directly control the judgment of time.

Tuesday, December 13, 2016

Feeling confident that you know? fMRI correlates of metacognitive accuracy.

The more confident you are, the less likely you are to be correct! From Molenberghs et al:
One important aspect of metacognition is the ability to accurately evaluate one’s performance. People vary widely in their metacognitive ability and in general are too confident when evaluating their performance. This often leads to poor decision making with potentially disastrous consequences. To further our understanding of the neural underpinnings of these processes, this fMRI study investigated inter-individual differences in metacognitive ability and effects of trial-by-trial variation in subjective feelings of confidence when making metacognitive assessments. Participants (N = 308) evaluated their performance in a high-level social and cognitive reasoning task. The results showed that higher metacognitive accuracy was associated with a decrease in activation in the anterior medial prefrontal cortex, an area previously linked to metacognition on perception and memory. Moreover, the feeling of confidence about one’s choices was associated with an increase of activation in reward, memory and motor related areas including bilateral striatum and hippocampus, while less confidence was associated with activation in areas linked with negative affect and uncertainty, including dorsomedial prefrontal and bilateral orbitofrontal cortex. This might indicate that positive affect is related to higher confidence thereby biasing metacognitive decisions towards overconfidence. In support, behavioural analyses revealed that increased confidence was associated with lower metacognitive accuracy.

Monday, December 12, 2016

Oxytocin, moral judgement, and male social synchony

I pass on two interesting pieces of work. First, Bernhard et al. show a correlation between different forms of the oxytocin receptor gene (which would influence neurotransmitters in multiple neural systems) and the kind of judgements made in complex moral situations. The technical abstract:
Moral judgments are produced through the coordinated interaction of multiple neural systems, each of which relies on a characteristic set of neurotransmitters. Genes that produce or regulate these neurotransmitters may have distinctive influences on moral judgment. Two studies examined potential genetic influences on moral judgment using dilemmas that reliably elicit competing automatic and controlled responses, generated by dissociable neural systems. Study 1 (N = 228) examined 49 common variants (SNPs) within 10 candidate genes and identified a nominal association between a polymorphism (rs237889) of the oxytocin receptor gene (OXTR) and variation in deontological vs utilitarian moral judgment (that is, judgments favoring individual rights vs the greater good). An association was likewise observed for rs1042615 of the arginine vasopressin receptor gene (AVPR1A). Study 2 (N = 322) aimed to replicate these findings using the aforementioned dilemmas as well as a new set of structurally similar medical dilemmas. Study 2 failed to replicate the association with AVPR1A, but replicated the OXTR finding using both the original and new dilemmas. Together, these findings suggest that moral judgment is influenced by variation in the oxytocin receptor gene and, more generally, that single genetic polymorphisms can have a detectable effect on complex decision processes.
Second, Mu et al. find that oxytocin enhances inter-brain synchrony during social coordination among adult men.
Recent brain imaging research has revealed oxytocin (OT) effects on an individual's brain activity during social interaction but tells little about whether and how OT modulates the coherence of inter-brain activity related to two individuals' coordination behavior. We developed a new real-time coordination game that required two individuals of a dyad to synchronize with a partner (coordination task) or with a computer (control task) by counting in mind rhythmically. Electroencephalography (EEG) was recorded simultaneously from a dyad to examine OT effects on inter-brain synchrony of neural activity during interpersonal coordination. Experiment 1 found that dyads showed smaller interpersonal time lags of counting and greater inter-brain synchrony of alpha-band neural oscillations during the coordination (vs control) task and these effects were reliably observed in female but not male dyads. Moreover, the increased alpha-band inter-brain synchrony predicted better interpersonal behavioral synchrony across all participants. Experiment 2, using a double blind, placebo-controlled between-subjects design, revealed that intranasal OT vs placebo administration in male dyads improved interpersonal behavioral synchrony in both the coordination and control tasks but specifically enhanced alpha-band inter-brain neural oscillations during the coordination task. Our findings provide first evidence that OT enhances inter-brain synchrony in male adults to facilitate social coordination.

Friday, December 09, 2016

Exhaustion is not unique to our overstimulated age.

Anna Katharina Schaffner, author of the book "Exhaustion: A History (2016), does a precis of its arguments,
Is ours the most exhausting age ever?..The argument goes that human energy levels have basically remained static throughout history, while the cognitive, emotional and temporal demands on the modern subject have increased so sharply that a chronic deficit of inner resources ensues...
..anxieties about exhaustion are not peculiar to our age. Those who imagine that life in the past was simpler, slower and better are wrong...exhaustion and its effects have preoccupied thinkers since classical antiquity...Over the centuries, medical, cultural, literary and biographical sources have cast exhaustion as a biochemical imbalance, a somatic ailment, a viral disease and a spiritual failing. It has been linked to loss, the alignment of the planets, a perverse desire for death, and social and economic disruption.
Exhaustion theories often address questions of responsibility, agency and willpower. In some accounts, exhaustion is represented as a form of weakness and lack of willpower, or even as a grave spiritual failing manifest in a bad mental attitude. For instance, medieval theories centred around the notion of acedia and sin, while recent neoliberal theories blame individuals for the management of their physical and mental wellbeing...Acedia literally denotes a ‘state of non-caring’, and has also been described as ‘weariness of the heart’. It primarily affected monks in late antiquity and the early medieval period, and was thought to be the result of a weak spiritual disposition and giving in to demonic temptations.
In Greek antiquity, a surplus of black bile that wreaks havoc with the bodily humoral economy was blamed. In the 19th century, it was a lack of nerve-power, and in the 20th and 21st centuries, a cognitive system chronically overstrained by external stimuli and stressors.
The 19th-century American physician George M Beard invented the neurasthenia diagnosis, a vaguely defined nervous exhaustion, and declared it to be a disease of civilisation, triggered by characteristics of the modern age, including ‘steam-power, the periodical press, the telegraph, the sciences, and the mental activity of women’...A century before Beard, the Scottish physician George Cheyne (1671-1743) already theorised the ‘English Malady’, manifest in a ‘Lowness of Spirits, lethargick Dullness, Melancholy and Moping’, and which he blamed on the fast-growing wealth of the sea-faring English nation and the adverse consequences of immoderation, laziness and luxury lifestyles. Burnout theorists of the 21st century are still making similar arguments about the damaging effects of new communication technologies and the neoliberal workplace.
...the continual production of theories about the loss of human energy is also an expression of timeless anxieties about death, ageing and the dangers of waning engagement. Theorising about exhaustion, and proposing cures and therapeutics for its effects, is a tactic to counteract the awareness of our helplessness in the face of our mortality. It is, in other words, a terror-management strategy designed to hold at bay our most existential fears – fears that are in no way peculiar to today.

Thursday, December 08, 2016

The rage against the elites...

Roger Cohen, always a perceptive commentator, really nails it in his recent Op-Ed Piece "The Rage of 2016". His closing paragraphs:
Western democracies are in the midst of an upheaval they only dimly grasp. Virtual direct democracy through social media has outflanked representative democracy. The impact of the smartphone on the human psyche is as yet scarcely understood; its addictiveness is treacherous and can be the enemy of thought. Mr. Trump hijacked the Republican Party like a man borrowing a dinner jacket for an evening. His campaign moved through Twitter to the aroused masses; it had no use or need for conventional channels. The major political parties in Britain and the United States will have to prove their relevance again.
Democracies, it is clear, have not been delivering to the less privileged, who were disenfranchised or discarded in the swirl of technology’s advance. A lot of thought is now needed to find ways to restore faith in liberal, free-market societies; to show that they can be fairer and more equitable and offer more opportunities across the social spectrum. Germany, with its successful balance of capitalism and solidarity, its respect for the labor force and its commitments to both higher education and technical training, offers one model. The rage of 2016 will not abate by itself.
The liberal elites’ arrogance and ignorance has been astounding. It is time to listen to the people who voted for change, be humble and think again. That, of course, does not mean succumbing to the hatemongers and racists among them: They must be fought every inch of the way. Nor does it mean succumbing to a post-truth society: Facts are the linchpins of progress. But so brutal a comeuppance cannot be met by more of the same. I fear for my children’s world, more than I ever imagined possible.

Wednesday, December 07, 2016

We should ask our elders how best to live.

I want to point to a brief essay by Pillemer in Aeon. His interviews with several thousand people in their 80s and 90s revealed that their common response to younger people seeking a goal or purpose in life was to tell them to relax...a life can have a number of purposes, which can shift and change as life situations, interests, and priorities change.
But how should you go about finding a direction? How to settle on a purpose that fits your current life stage? One technique turns out to be immensely valuable – and yet most people ignore it. If you are searching for a direction or purpose, interview your future self...when people are made to think in detail about their future selves, they are more likely to make better financial planning decisions, show altruistic behaviour, and make more ethical choices. But it’s hard to do.
He gives advice similar to that given by Daniel Gilbert in his book "Stumbling towards happiness," a book which I abstracted in a series of MindBlog posts June 29, 2006.’s astonishing how few people do the next best thing: interview an older person who embodies the ‘self’ they would like to be...In any period where you feel directionless, wavering, stuck with one foot in two different worlds, and hearing in the back of your mind the song lyrics ‘Should I stay or should I go?’ – find your future self. He or she should be old – and preferably really old. You don’t want a 40-year-old if you are 20; you want someone in his or her 80s, 90s, or a centenarian if you can find one. You need your future self to have the truly long view, as well as the detachment that comes from a very long life.
This person also needs to be as close as possible to your imagined future self. Debating a career in medicine? Find a doctor who loved what she did. Worried about whether you can balance your values with a career in the financial services industry? Find an older person who struck that balance and made it to the end of life without regrets. Planning to work an undemanding day job so you have the energy to paint/write/act in your spare time? Some very old people did just that

Tuesday, December 06, 2016

Protecting and reactivating memories

I want to point to two recent Science Magazine articles on memory. From the magazine's summaries..

Protecting memories from stress
It is widely accepted that stress has a negative impact on memory retrieval. But specific approaches to learning can counteract this effect. Smith et al. found that when memory was tested immediately after the onset of stress, stress effects were reduced. Furthermore, when subjects learned novel material by using a highly effective learning technique involving practice tests, their memory was also protected against the negative effects of stress.
Smith et al. Abstract:
More than a decade of research has supported a robust consensus: Acute stress impairs memory retrieval. We aimed to determine whether a highly effective learning technique could strengthen memory against the negative effects of stress. To bolster memory, we used retrieval practice, or the act of taking practice tests. Participants first learned stimuli by either restudying or engaging in retrieval practice. Twenty-four hours later, we induced stress in half of the participants and assessed subsequent memory performance. Participants who learned by restudying demonstrated the typical stress-related memory impairment, whereas those who learned by retrieval practice were immune to the deleterious effects of stress. These results suggest that the effects of stress on memory retrieval may be contingent on the strength of the memory representations themselves.
How to reactivate forgotten memories
Sophisticated techniques can decode stimulus representations for items held in a person's working memory. However, when subjects shift their attention toward something else, the neural representation of the now unattended item drops to baseline, as though the item has been forgotten. Rose et al. used single-pulse transcranial magnetic stimulation (TMS) to briefly reactivate the representation of an unattended item. A short pulse of TMS enhanced recognition of “forgotten” stimuli, bringing an unattended item back into focal attention.
Rose et al. Abstract:
The ability to hold information in working memory is fundamental for cognition. Contrary to the long-standing view that working memory depends on sustained, elevated activity, we present evidence suggesting that humans can hold information in working memory via “activity-silent” synaptic mechanisms. Using multivariate pattern analyses to decode brain activity patterns, we found that the active representation of an item in working memory drops to baseline when attention shifts away. A targeted pulse of transcranial magnetic stimulation produced a brief reemergence of the item in concurrently measured brain activity. This reactivation effect occurred and influenced memory performance only when the item was potentially relevant later in the trial, which suggests that the representation is dynamic and modifiable via cognitive control. The results support a synaptic theory of working memory.

Monday, December 05, 2016

Reversing the effect of booze on the brain.

Assuming that data on female rats can be extrapolated to humans, a bit of work that makes me feel better about my daily habits of aerobic swimming and a robust happy hour...Maynard and Leasure show that loss of nerve cells caused by binge drinking can be reversed by exercise, which acts to promote natural self-repair processes.:
Binge drinking damages the brain, and although a significant amount of recovery occurs with abstinence, there is a need for effective strategies to maximize neurorestoration. In contrast to binge drinking, exercise promotes brain health, so the present study assessed whether it could counteract ethanol-induced damage by augmenting natural self-repair processes following one or more binge exposures. Adult female rats were exposed to 0 (control), 1 or 2 binges, using an established 4-day model of binge-induced neurodegeneration. Half of the animals in each group remained sedentary, or had running wheel access beginning 7 days after the final binge, and were sacrificed 28 days later. To assess binge-induced hippocampal damage and exercise restoration, we quantified volume of the dentate gyrus and number of granule neurons. We found that a single binge exposure significantly decreased the volume of the dentate gyrus and number of granule neurons. A second binge did not exacerbate the damage. Exercise completely restored baseline volume and granule neuron numbers. To investigate a potential mechanism of this restoration, we administered IdU (a thymidine analog) in order to label cells generated after the first binge. Previous studies have shown that neurogenesis in the dentate gyrus is decreased by binge alcohol exposure, and that the hippocampus responds to this insult by increasing cell genesis during abstinence. We found increased IdU labeling in binge-exposed animals, and a further increase in binged animals that exercised. Our results indicate that exercise reverses long-lasting hippocampal damage by augmenting natural self-repair processes.

Friday, December 02, 2016

The brain adapts to dishonesty.

From Garrett et al., some information on neural correlates of what might be going on in Donald Trump's brain....
Dishonesty is an integral part of our social world, influencing domains ranging from finance and politics to personal relationships. Anecdotally, digressions from a moral code are often described as a series of small breaches that grow over time. Here we provide empirical evidence for a gradual escalation of self-serving dishonesty and reveal a neural mechanism supporting it. Behaviorally, we show that the extent to which participants engage in self-serving dishonesty increases with repetition. Using functional MRI, we show that signal reduction in the amygdala is sensitive to the history of dishonest behavior, consistent with adaptation. Critically, the extent of reduced amygdala sensitivity to dishonesty on a present decision relative to the previous one predicts the magnitude of escalation of self-serving dishonesty on the next decision. The findings uncover a biological mechanism that supports a 'slippery slope': what begins as small acts of dishonesty can escalate into larger transgressions.

Thursday, December 01, 2016

Genetic variants linked to education predict longevity

I'll follow yesterday's post on genetic variation and societal outcomes by passing on yet another piece, this one from Marioni et al.:

Individuals with more education tend to live longer. Genetic variants have been discovered that predict educational attainment. We tested whether a “polygenic score” based on these genetic variants could make predictions about people’s lifespan. We used data from three cohort studies (including >130,000 participants) to examine the link between offspring polygenic score for education and parental longevity. Across the studies, we found that participants with more education-linked genetic variants had longer-living parents; compared with those with the lowest genetic education scores, those with the highest scores had parents who lived on average 6 months longer. This finding suggests the hypothesis that part of the ultimate explanation for the extended longevity of better-educated people is an underlying, quantifiable, genetic propensity.
Educational attainment is associated with many health outcomes, including longevity. It is also known to be substantially heritable. Here, we used data from three large genetic epidemiology cohort studies (Generation Scotland, n = ∼17,000; UK Biobank, n = ∼115,000; and the Estonian Biobank, n = ∼6,000) to test whether education-linked genetic variants can predict lifespan length. We did so by using cohort members’ polygenic profile score for education to predict their parents’ longevity. Across the three cohorts, meta-analysis showed that a 1 SD higher polygenic education score was associated with ∼2.7% lower mortality risk for both mothers (total ndeaths = 79,702) and ∼2.4% lower risk for fathers (total ndeaths = 97,630). On average, the parents of offspring in the upper third of the polygenic score distribution lived 0.55 y longer compared with those of offspring in the lower third. Overall, these results indicate that the genetic contributions to educational attainment are useful in the prediction of human longevity.

Wednesday, November 30, 2016

Genetic correlates of social deprivation and household income

From Hill et al.:

•Common SNPs (single nucleotide polymorphisms) explain 21% of social deprivation and 11% of household income 
•Two loci attained genome-wide significance for household income 
•Genes in these loci have been linked to synaptic plasticity 
•Genetic correlations were found between both measures of SES and many other traits
Individuals with lower socio-economic status (SES) are at increased risk of physical and mental illnesses and tend to die at an earlier age. Explanations for the association between SES and health typically focus on factors that are environmental in origin. However, common SNPs have been found collectively to explain around 18% of the phenotypic variance of an area-based social deprivation measure of SES. Molecular genetic studies have also shown that common physical and psychiatric diseases are partly heritable. It is possible that phenotypic associations between SES and health arise partly due to a shared genetic etiology. We conducted a genome-wide association study (GWAS) on social deprivation and on household income using 112,151 participants of UK Biobank. We find that common SNPs explain 21% of the variation in social deprivation and 11% of household income. Two independent loci attained genome-wide significance for household income, with the most significant SNP in each of these loci being rs187848990 on chromosome 2 and rs8100891 on chromosome 19. Genes in the regions of these SNPs have been associated with intellectual disabilities, schizophrenia, and synaptic plasticity. Extensive genetic correlations were found between both measures of SES and illnesses, anthropometric variables, psychiatric disorders, and cognitive ability. These findings suggest that some SNPs associated with SES are involved in the brain and central nervous system. The genetic associations with SES obviously do not reflect direct causal effects and are probably mediated via other partly heritable variables, including cognitive ability, personality, and health.

Tuesday, November 29, 2016

More exercise, less depression.

Reynolds points to a number of interesting meta-analyses that pool outcomes from past research involving more than a million men and women to show that regular exercise makes us more resistant to depression. Schuch et al. find: and women with the lowest fitness were about 75 percent more likely to have been given diagnoses of depression than the people with the greatest fitness. The men and women in the middle third were almost 25 percent more likely to develop depression than those who were the most fit.
Some of the same authors pooled results from 25 studies that evaluated exercise as a treatment for depression:
...pooled results persuasively showed that exercise, especially if it is moderately strenuous, such as brisk walking or jogging, and supervised, so that people complete the entire program, has a “large and significant effect” against depression
And, on mechanisms, a clip from another Schuch et al. piece combining the results of twenty studies involving 1353 people to evaluate the neurobiological effects of exercise among people with major depressive disorder (MDD)...
The results demonstrate that a single bout of exercise increases atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), copepetin and growth hormone among people with MDD. Exercise also potentially promotes long-term adaptations of copeptin, thiobarbituric acid reactive species (TBARS) and total mean frequency (TMF). However, there is limited evidence that exercise promotes adaptations on neurogenesis, inflammation biomarkers and brain structure. Associations between depressive symptoms improvement and hippocampus volume and IL-1β were found. Nevertheless, the paucity of studies and limitations presented within, precludes a more definitive conclusion of the underlying neurobiological explanation for the antidepressant effect of exercise in people with MDD.

Monday, November 28, 2016

Networks of conforming or nonconforming individuals always reach a satisfactory state

Here is an intriguing study from Ramazi et al., who use linear-threshold-based dynamic models to show that whether individuals go with or against the crowd, a stable and satisfactory outcome results. (The model code, given in the text of the article, I don't even begin to I take their word for the results.)
Binary decisions of agents coupled in networks can often be classified into two types: “coordination,” where an agent takes an action if enough neighbors are using that action, as in the spread of social norms, innovations, and viral epidemics, and “anticoordination,” where too many neighbors taking a particular action causes an agent to take the opposite action, as in traffic congestion, crowd dispersion, and division of labor. Both of these cases can be modeled using linear-threshold–based dynamics, and a fundamental question is whether the individuals in such networks are likely to reach decisions with which they are satisfied. We show that, in the coordination case, and perhaps more surprisingly, also in the anticoordination case, the agents will indeed always tend to reach satisfactory decisions, that is, the network will almost surely reach an equilibrium state. This holds for every network topology and every distribution of thresholds, for both asynchronous and partially synchronous decision-making updates. These results reveal that irregular network topology, population heterogeneity, and partial synchrony are not sufficient to cause cycles or nonconvergence in linear-threshold dynamics; rather, other factors such as imitation or the coexistence of coordinating and anticoordinating agents must play a role.

Friday, November 25, 2016

Online social interaction associated with reduced mortality risk.

Hobbs et al. apply longitudinal statistical models to two massive databases to show that online social interactions, just like old-fashioned networks in the offline world, correlate with increased longevity:
Social interactions increasingly take place online. Friendships and other offline social ties have been repeatedly associated with human longevity, but online interactions might have different properties. Here, we reference 12 million social media profiles [of Facebook users] against California Department of Public Health vital records and use longitudinal statistical models to assess whether social media use is associated with longer life. The results show that receiving requests to connect as friends online is associated with reduced mortality but initiating friendships is not. Additionally, online behaviors that indicate face-to-face social activity (like posting photos) are associated with reduced mortality, but online-only behaviors (like sending messages) have a nonlinear relationship, where moderate use is associated with the lowest mortality. These results suggest that online social integration is linked to lower risk for a wide variety of critical health problems. Although this is an associational study, it may be an important step in understanding how, on a global scale, online social networks might be adapted to improve modern populations’ social and physical health.

Thursday, November 24, 2016

Stock trading - gut feelings help with risky decisions.

I've done a number of posts describing studies trying to determine what characteristics might distinguish successful stock traders (enter 'traders' in the MindBlog search box.) Here is a further offering in this vein from Kandasamy et al. correlating interoceptive ability with survival on a London trading floor:
Interoception is the sensing of physiological signals originating inside the body, such as hunger, pain and heart rate. People with greater sensitivity to interoceptive signals, as measured by, for example, tests of heart beat detection, perform better in laboratory studies of risky decision-making. However, there has been little field work to determine if interoceptive sensitivity contributes to success in real-world, high-stakes risk taking. Here, we report on a study in which we quantified heartbeat detection skills in a group of financial traders working on a London trading floor. We found that traders are better able to perceive their own heartbeats than matched controls from the non-trading population. Moreover, the interoceptive ability of traders predicted their relative profitability, and strikingly, how long they survived in the financial markets. Our results suggest that signals from the body - the gut feelings of financial lore - contribute to success in the markets.

Wednesday, November 23, 2016

The teenage brain and the pleasure of “likes”

Rabin points to work by Sherman et al. showing that positive feedback given to a teenager's post on social media ('likes') stimulates the same reward center in the brain activated by thoughts of sex, money or ice cream...
We investigated a unique way in which adolescent peer influence occurs on social media. We developed a novel functional MRI (fMRI) paradigm to simulate Instagram, a popular social photo-sharing tool, and measured adolescents' behavioral and neural responses to likes, a quantifiable form of social endorsement and potential source of peer influence. Adolescents underwent fMRI while viewing photos ostensibly submitted to Instagram. They were more likely to like photos depicted with many likes than photos with few likes; this finding showed the influence of virtual peer endorsement and held for both neutral photos and photos of risky behaviors (e.g., drinking, smoking). Viewing photos with many (compared with few) likes was associated with greater activity in neural regions implicated in reward processing, social cognition, imitation, and attention. Furthermore, when adolescents viewed risky photos (as opposed to neutral photos), activation in the cognitive-control network decreased. These findings highlight possible mechanisms underlying peer influence during adolescence.

Tuesday, November 22, 2016

Social media's globe-shaking power.

Like many of you, I am more than completely overwhelmed by recent political events and the avalanche of thoughtful commentary on them. I am one of a group of retired guys here in Fort Lauderdale whose members have been spamming each other with interesting articles we find. I am particularly struck by a piece from NYTimes columnist Farhad Manjoo on how the world I assumed I was living in has been shattered. Below are some edited and rearranged clips.

Starting with the recent election...
...widespread misinformation spread online was a primary factor in the race’s outcome...On Monday, both Google and Facebook altered their advertising policies to explicitly prohibit sites that traffic in fake news from making money off lies. That’s very likely a worthwhile fix, even if it comes too late. The internet has loosened our collective grasp on the truth...the dangers posed by fake news are just a symptom of a deeper truth... social media (such as Facebook, WhatsApp, WeChat, Instagram, Twitter, Weibo, etc.) has become an increasingly powerful cultural and political force, to the point that its effects are now beginning to alter the course of global events.
The election of Donald J. Trump is perhaps the starkest illustration yet that across the planet, social networks are helping to fundamentally rewire human society. They have subsumed and gutted mainstream media. They have undone traditional political advantages like fund-raising and access to advertising. And they are destabilizing and replacing old-line institutions and established ways of doing things, including political parties, transnational organizations and longstanding, unspoken social prohibitions against blatant expressions of racism and putting out a message that resonated with people online, Mr. Trump hacked through every established political order...Most important, because these services allow people to communicate with one another more freely, they are helping to create surprisingly influential social organizations among once-marginalized groups.
There has been a
...shifting of the "Overton Window,” a term coined by the researcher Joseph P. Overton to describe the range of subjects that the mainstream media deems publicly acceptable to discuss...From about the early 1980s until the very recent past, it was usually considered unwise for politicians to court views deemed by most of society to be out of the mainstream, things like overt calls to racial bias (there were exceptions, of course, like the Willie Horton ad). But the internet shifted that each person with once-maligned views can see that he’s not alone. And when these people find one another, they can do things — create memes, publications and entire online worlds that bolster their worldview, and then break into the mainstream. The groups also become ready targets for political figures like Mr. Trump, who recognize their energy and enthusiasm and tap into it for real-world victories...the Overton Window isn’t just shifting on the right. We see it happening on the left, too. Mr. Sanders campaigned on an anti-Wall Street platform that would have been unthinkable for a Democrat just a decade ago.
Mr. Trump is just the tip of the iceberg. Prepare for interesting times.

Monday, November 21, 2016

Sex differences in brain regulation of aggression

Interesting work from Terranova et al., done with hamsters, and almost certainly applicable to us humans. Here is their summary of the significance of the study, and the abstract with more technical stuff:

There are profound sex differences in the expression of social behavior and in the incidence of many psychiatric disorders, and yet little is known about how the brain mechanisms underlying these phenomena differ in females and males. Here, we report that serotonin (5-HT) and arginine–vasopressin (AVP) act in opposite ways within the hypothalamus to regulate dominance and aggression in females and males. Dominance and aggression are promoted by 5-HT in females and by AVP in males. Because dominance and aggressiveness have been linked to the resistance to stress-related psychiatric disorders, these disorders may be more effectively treated with 5-HT–targeted drugs in females and AVP-targeted drugs in males.
There are profound sex differences in the incidence of many psychiatric disorders. Although these disorders are frequently linked to social stress and to deficits in social engagement, little is known about sex differences in the neural mechanisms that underlie these phenomena. Phenotypes characterized by dominance, competitive aggression, and active coping strategies appear to be more resilient to psychiatric disorders such as posttraumatic stress disorder (PTSD) compared with those characterized by subordinate status and the lack of aggressiveness. Here, we report that serotonin (5-HT) and arginine–vasopressin (AVP) act in opposite ways in the hypothalamus to regulate dominance and aggression in females and males. Hypothalamic injection of a 5-HT1a agonist stimulated aggression in female hamsters and inhibited aggression in males, whereas injection of AVP inhibited aggression in females and stimulated aggression in males. Striking sex differences were also identified in the neural mechanisms regulating dominance. Acquisition of dominance was associated with activation of 5-HT neurons within the dorsal raphe in females and activation of hypothalamic AVP neurons in males. These data strongly indicate that there are fundamental sex differences in the neural regulation of dominance and aggression. Further, because systemically administered fluoxetine increased aggression in females and substantially reduced aggression in males, there may be substantial gender differences in the clinical efficacy of commonly prescribed 5-HT–active drugs such as selective 5-HT reuptake inhibitors. These data suggest that the treatment of psychiatric disorders such as PTSD may be more effective with the use of 5-HT–targeted drugs in females and AVP-targeted drugs in males.

Friday, November 18, 2016

Are your emotions 'Black and White' or 'Shades of Gray'? - Brain correlates.

Satpute et al. show that how we think about emotion shapes our perception and neural representation of emotion. They asked subjects to judge emotional expressions as fearful or calm using either categorical terms or a continuous scale. They found that categorical-thinking-induced shifts in emotion perception toward “fear” or toward “calm” were associated with corresponding shifts in neural activity.:
The demands of social life often require categorically judging whether someone’s continuously varying facial movements express “calm” or “fear,” or whether one’s fluctuating internal states mean one feels “good” or “bad.” In two studies, we asked whether this kind of categorical, “black and white,” thinking can shape the perception and neural representation of emotion. Using psychometric and neuroimaging methods, we found that (a) across participants, judging emotions using a categorical, “black and white” scale relative to judging emotions using a continuous, “shades of gray,” scale shifted subjective emotion perception thresholds; (b) these shifts corresponded with activity in brain regions previously associated with affective responding (i.e., the amygdala and ventral anterior insula); and (c) connectivity of these regions with the medial prefrontal cortex correlated with the magnitude of categorization-related shifts. These findings suggest that categorical thinking about emotions may actively shape the perception and neural representation of the emotions in question.

Thursday, November 17, 2016

Thoughts about Dying in America.

Pizzo offers a summary of a recent Institute of Medicine report, with the title "Thoughts about Dying in America: Enhancing the impact of one’s life journey and legacy by also planning for the end of life."
This Perspective offers a summary of the recommendations in the Institute of Medicine report Dying in America. How we die is a deeply personal issue that each of us will face. However, the approach to end-of-life (EOL) care in the United States needs improvement. Too frequently, healthcare delivery is uncoordinated and has many providers who are not adequately prepared to have meaningful conversations about EOL planning. This is amplified by payment systems and policies that create impediments, misunderstanding, and sometimes misinformation. Dying in America made five recommendations to improve quality and honor individual preferences near the EOL beginning with making conversations with providers and families something that occurs during various phases of the life cycle and not just when one is facing serious illness or possible EOL. It was recommended (i) that public and private payers and care delivery organizations cover the provision of comprehensive care that is accessible and available to individuals on a 24/7 schedule; (ii) that professional societies and other entities establish standards for clinician patient communication and advance care planning and that payers and care delivery organizations adopt them; (iii) that educational institutions, credentialing bodies, accrediting boards, state regulatory agencies, and care delivery organizations establish palliative care training, certification, and/or licensure requirements; (iv) that public and private payers and care delivery organizations integrate the financing of health and social services; and (v) that public and private organizations should engage their constituents and provide fact-based information to encourage advance care planning and informed choice.

Wednesday, November 16, 2016

Our working memory modulates our conscious access to suppressed threatening information.

Our processing of emotional information is susceptible to working memory (WM) modulations - emotional faces trigger much stronger responses in the fronto-thalamic occipital network when they match an emotional word held in WM than when they do not. Liu et al. show that WM tasks can also influence the nonconscious processing of emotional signals. Their explanation of the procedure used:
We used a modified version of the delayed-match-to-sample paradigm. Specifically, participants were instructed to keep a face (either fearful or neutral) in WM while performing a target-detection task. The target, another face with a new identity (fearful or neutral), was suppressed from awareness utilizing continuous flash suppression. In this technique, the target is monocularly presented and hidden from visual awareness by simultaneously presenting dynamic noise to the other eye. We measured the time it took for the suppressed face to emerge from suppression. We specifically tested whether faces would emerge from suppression more quickly if they matched the emotional valence of WM contents than if they did not.
Here is their abstract:
Previous research has demonstrated that emotional information processing can be modulated by what is being held in working memory (WM). Here, we showed that such content-based WM effects can occur even when the emotional information is suppressed from conscious awareness. Using the delayed-match-to-sample paradigm in conjunction with continuous flash suppression, we found that suppressed threatening (fearful and angry) faces emerged from suppression faster when they matched the emotional valence of WM contents than when they did not. This effect cannot be explained by perceptual priming, as it disappeared when the faces were only passively viewed and not held in WM. Crucially, such an effect is highly specific to threatening faces but not to happy or neutral faces. Our findings together suggest that WM can modulate nonconscious emotion processing, which highlights the functional association between nonconsciously triggered emotional processes and conscious emotion representation.

Tuesday, November 15, 2016

View a flickering stimulus before you try to read fine print…

A nice piece of work from Arnold et al.:

Distinct anatomical visual pathways can be traced through the human central nervous system. These have been linked to specialized functions, such as encoding information about spatial forms (like the human face and text) and stimulus dynamics (flicker or movement). Our experiments are inconsistent with this strict division. They show that mechanisms responsive to flicker can alter form perception, with vision transiently sharpened by weakening the influence of flicker-sensitive mechanisms by prolonged exposure to flicker. So, next time you are trying to read fine print, you might be well advised to first view a flickering stimulus!
Human vision is surprisingly malleable. A static stimulus can seem to move after prolonged exposure to movement (the motion aftereffect), and exposure to tilted lines can make vertical lines seem oppositely tilted (the tilt aftereffect). The paradigm used to induce such distortions (adaptation) can provide powerful insights into the computations underlying human visual experience. Previously spatial form and stimulus dynamics were thought to be encoded independently, but here we show that adaptation to stimulus dynamics can sharpen form perception. We find that fast flicker adaptation (FFAd) shifts the tuning of face perception to higher spatial frequencies, enhances the acuity of spatial vision—allowing people to localize inputs with greater precision and to read finer scaled text, and it selectively reduces sensitivity to coarse-scale form signals. These findings are consistent with two interrelated influences: FFAd reduces the responsiveness of magnocellular neurons (which are important for encoding dynamics, but can have poor spatial resolution), and magnocellular responses contribute coarse spatial scale information when the visual system synthesizes form signals. Consequently, when magnocellular responses are mitigated via FFAd, human form perception is transiently sharpened because “blur” signals are mitigated.

Monday, November 14, 2016

Why do people in big cities move faster?

A number of studies have shown that people in big cities move faster. Why is this? Pontzer describes work by Ahmed et al. suggesting that our brains use metabolic energy cost to determine the speed with which we (and other animals) move towards a reward.

For many tasks, such as walking, the metabolic energy (i.e., calories) expended per distance traveled is a function of speed; moving faster requires more energy per meter. A reward’s value can be a function of speed as well. Under a temporal discounting model, a reward’s value decreases the longer it takes to obtain it; food might decay or be lost to competitors, the comfortable seats on the rush-hour train might be taken. Given the cost:speed function for a given task and the value:time function for a given reward, one can solve for the speed that maximizes net return for a given action.
Ahmed and colleagues tested their model in a series of reaching tasks with human subjects and found strong support for it...despite its simplicity the model makes reliable predictions across a variety of different tasks and even across species. Analyzing the behavior of finches reported in an experimental study of foraging behavior, Ahmed and colleagues showed that their model correctly predicts whether the birds chose to walk (which is slow but metabolically inexpensive) or fly (fast but costly) to acquire food. When the time to acquire the food increased, its value as estimated by the discounting model decreased, and as predicted the birds chose to walk. In a separate analysis of isometric force production in human subjects, their model correctly predicted subjects’ decreasing sensitivity to task duration as the force exerted decreased.
That the model’s predictions work well across species suggests it may reflect a common, evolved neurobiological mechanism that is shared across species. Ahmed and colleagues suggest, for example, that the neural circuits involved in generating actions should be strongly coupled to the circuits involved in deciding between actions. Such shared, evolved neurological mechanisms are powerful tools for research, as they present a common framework for comparing behavioral strategies across species, tasks, and environments.
Pontzer's final paragraph:
For my fellow New Yorkers, Ahmed and colleagues’ model suggests two, mutually compatible reasons that we habitually walk faster, and less efficiently, than our relaxed, rural comrades (see figure above). We may perceive greater rewards are at stake, and given the remarkable sums of money exchanged each day in the city, that assessment may well be accurate for some. Alternatively, with over 8 million fellow primates foraging for the same resources, we may sense that the rewards we seek are slipping away more quickly — something to ponder next time you’re running for the train.
The mathematical model developed by Ahmed et al. is a bit more complex than is appropriate for a description here, but can be found in their paper.

Friday, November 11, 2016

Social class and attentiveness to others.

More on “The rich are different from you and me.” (F. Scott Fitzgerald) “Yes, They have more money.” (Hemingway). Dietze and Knowles use eye movement measurements to show that people of higher social class are less attentive to other people and their faces. Their abstract, slightly edited:
We theorize that people’s social class affects their appraisals of others’ motivational relevance—the degree to which others are seen as potentially rewarding, threatening, or otherwise worth attending to. Supporting this account, three studies indicate that social classes differ in the amount of attention their members direct toward other human beings. In the first study, wearable technology was used to film the visual fields of pedestrians on city streets; higher-class participants looked less at other people than did lower-class participants. A second study tracked participants’ eye movements while they viewed street scenes; higher class was associated with reduced attention to people in the images. Finally a third study used a change-detection procedure to assess the degree to which human faces spontaneously attract visual attention; faces proved less effective at drawing the attention of high-class than low-class participants, which implies that class affects spontaneous relevance appraisals. The measurement and conceptualization of social class are discussed.

Thursday, November 10, 2016

Explaining gender differences in anxiety.

Li et al. find that a set of oxytocin-responsive neurons in the medial prefrontal cortex (mPFC) look similar in both sexes, but in males they secrete a protein (CRHBP) that antagonizes the effect of the corticotropin-releasing hormone (CRH) associated with stress, thus causing an anti-anxiety effect with males that is not seen in females. This suggests the possibility of developing gender specific therapies for anxiety.

•Activation of OxtrINs (oxytocin receptor interneurons) is anxiolytic in males and prosocial in females 
•OxtrINs specifically express CRHBP, an inhibitor of the stress hormone CRH 
•CRHBP blocks activation of layer 2/3 pyramidal cells by CRH only in males 
•OxtrINs in the mPFC (medial prefrontal cortex) coordinate sexually dimorphic social/emotional behaviors
The frequency of human social and emotional disorders varies significantly between males and females. We have recently reported that oxytocin receptor interneurons (OxtrINs) modulate female sociosexual behavior. Here, we show that, in male mice, OxtrINs regulate anxiety-related behaviors. We demonstrate that corticotropin-releasing-hormone-binding protein (CRHBP), an antagonist of the stress hormone CRH, is specifically expressed in OxtrINs. Production of CRHBP blocks the CRH-induced potentiation of postsynaptic layer 2/3 pyramidal cell activity of male, but not female, mice, thus producing an anxiolytic effect. Our data identify OxtrINs as critical for modulation of social and emotional behaviors in both females and males and reveal a molecular mechanism that acts on local medial prefrontal cortex (mPFC) circuits to coordinate responses to OXT and CRH. They suggest that additional studies of the impact of the OXT/OXTR and CRHBP/CRH pathways in males and females will be important in development of gender-specific therapies.

Wednesday, November 09, 2016

The presidential election has spawned an effusion of interesting essays - a sampling

A rich trove of Op-Ed pieces and essays has emerged during the recent presidential campaign. I’ve accumulated a list of links, thinking each article might merit an individual blog post, but the list has become overwhelming, like everything else in the campaign. Instead of letting the list entirely fade away, I thought I would pass on selected links, with a brief note on the content of each article:

Behind Our Anxiety, The Fear of Being Unneeded. An interesting collaboration between the conservative president of the American Enterprise Institute and the Dalai Lama. It's message is that our current anxiety and malaise stems not from material needs, but from the growing number of people who feel they are no longer useful, no longer needed, no longer one with their societies. What is needed is the building of a compassionate society that creates a wealth of opportunities for meaningful work in the service of others, so that everyone who is capable of contributing can do so.

Hillary Clinton’s Juggling Act. Hillary Clinton must juggle three competing interest groups: her party’s upscale pro-trade, globalist wing; its underdog minority wing; and organized labor. She is paying a price for her triple allegiance.

The Ethics of Globalism, Nationalism, and Patriotism. A thoughtful article noting a fundamental cause of the division between globalists and nationalists: their underlying theories of human nature, the “unconstrained vision” and the “constrained vision.” If you really believe that the world is “full of good people,” then why not lower the drawbridge and leave it down? But if you have a darker view of human nature and are inclined to see more threats in the world, then you’ll want to retain full control of the drawbridge, lower it selectively, and check people’s papers before you let them in. He quotes from a David Brooks essay "The way out of this debate is not to go nationalist or globalist. It’s to return to American nationalism—espoused by people like Walt Whitman—which combines an inclusive definition of who is Our Own with a fervent commitment to assimilate and Take Care of them."

The Price of Certainty. A piece, with a video, on the work of social psychologist Arie Kruglanski, and his theory of "cognitive closure." Closure is the moment that you make a decision or form a judgment. You literally close your mind to new information. If you have high need for closure, you tend to make decisions quickly and see the world in black and white. If you have a low need for closure, you tolerate ambiguity, but often have difficulty making decisions. All of us fall naturally somewhere on this spectrum...But during times of fear and anxiety — like, for example, right now — everybody’s need for closure increases. We tend to make judgments more quickly, regardless of the facts. We’re also drawn to leaders who are decisive and paint solutions in simple terms.

The Case Against Democracy. An interesting essay Caleb Crain in The New Yorker on the history of the idea of “epistocracy,” meaning “government by the knowledgeable.”