Some brain benefits of exercise evaporate after a short rest.

Gretchen Reynolds points to a study by kinesiologists at the Univ. of Maryland that probed what happens when very active and fit people stop exercising for awhile. They found that after ten days of inactivity, blood flow to many parts of the brain diminishes, particularly to the hippocampus, which is important in learning and memory. Here's the abstract:

While endurance exercise training improves cerebrovascular health and has neurotrophic effects within the hippocampus, the effects of stopping this exercise on the brain remain unclear. Our aim was to measure the effects of 10 days of detraining on resting cerebral blood flow (rCBF) in gray matter and the hippocampus in healthy and physically fit older adults. We hypothesized that rCBF would decrease in the hippocampus after a 10-day cessation of exercise training. Twelve master athletes, defined as older adults (age 50 years or older) with long-term endurance training histories (at least 15 years), were recruited from local running clubs. After screening, eligible participants were asked to cease all training and vigorous physical activity for 10 consecutive days. Before and immediately after the exercise cessation period, rCBF was measured with perfusion-weighted MRI. A voxel-wise analysis was used in gray matter, and the hippocampus was selected a priori as a structurally defined region of interest (ROI), to detect rCBF changes over time. Resting CBF significantly decreased in eight gray matter brain regions. These regions included: (L) inferior temporal gyrus, fusiform gyrus, inferior parietal lobule, (R) cerebellar tonsil, lingual gyrus, precuneus, and bilateral cerebellum (FWE p less than 0.05). Additionally, rCBF within the left and right hippocampus significantly decreased after 10 days of no exercise training. These findings suggest that the cerebrovascular system, including the regulation of resting hippocampal blood flow, is responsive to short-term decreases in exercise training among master athletes. Cessation of exercise training among physically fit individuals may provide a novel method to assess the effects of acute exercise and exercise training on brain function in older adults.

A way to change adult behaviors - debiasing decisions.

Hambrick and Burgoyne do a piece on the difference between rationality and intelligence. Starting from Kahneman and Tversky's work in the early 1970's, countless experiments by now have shown that we are frequently prone to make decisions based on faulty intuition rather than reason. Further, a person with high I.Q. (which reflects abstract reasoning and verbal ability) is no less likely to display "dysrationalia." They point to experiments by Morewedge and colleagues showing that rationality, unlike intelligence, can be improved by a single video or computer training session that illustrates decision-making biases. The improvement was still observed two months later in a different version of the decision-making test. Here is their abstract:

From failures of intelligence analysis to misguided beliefs about vaccinations, biased judgment and decision making contributes to problems in policy, business, medicine, law, education, and private life. Early attempts to reduce decision biases with training met with little success, leading scientists and policy makers to focus on debiasing by using incentives and changes in the presentation and elicitation of decisions. We report the results of two longitudinal experiments that found medium to large effects of one-shot debiasing training interventions. Participants received a single training intervention, played a computer game or watched an instructional video, which addressed biases critical to intelligence analysis (in Experiment 1: bias blind spot, confirmation bias, and fundamental attribution error; in Experiment 2: anchoring, representativeness, and social projection). Both kinds of interventions produced medium to large debiasing effects immediately (games ~ −31.94% and videos ~ −18.60%) that persisted at least 2 months later (games ~ −23.57% and videos ~ −19.20%). Games that provided personalized feedback and practice produced larger effects than did videos. Debiasing effects were domain general: bias reduction occurred across problems in different contexts, and problem formats that were taught and not taught in the interventions. The results suggest that a single training intervention can improve decision making. We suggest its use alongside improved incentives, information presentation, and nudges to reduce costly errors associated with biased judgments and decisions.

MindBlog, hurricane Matthew, and a personal note

I have a few MindBlog posts in a queue to be automatically posted by Blogger, but want to mention that there might be a hiatus in posts caused by the fact that my Fort Lauderdale condo appears to be in the direct path of hurricane Matthew, expected to hit this evening sometime. Power and communications might be down for some days. (Update...Friday, Oct. 7, the hurricane passed just north of Fort Lauderdale, so modest rain, wind, and no power outages.)

I will add another personal note. Over the years, I have done occasional MindBlog posts with YouTube videos of my piano performances on the Steinway B at the 1860 stone schoolhouse that has been my residence during my years as a professor at the University of Wisconsin, Madison. On this coming Monday, ownership of this home will pass to family with young children that is very excited to begin exploring their new country setting. The Steinway B is now in my Florida condo.

A way to change adolescent behaviors?

Bryan et al. present an interesting strategy for the difficult task of changing adolescent behaviors:

Significance

Behavioral science has rarely offered effective strategies for changing adolescent health behavior. One limitation of previous approaches may be an overemphasis on long-term health outcomes as the focal source of motivation. The present research uses a rigorous randomized trial to evaluate an approach that aligns healthy behavior with values about which adolescents already care: feeling like a socially conscious, autonomous person worthy of approval from one’s peers. It improved the health profile of snacks and drinks participants chose in an ostensibly unrelated context and did so because it caused adolescents to construe the healthy behavior as being aligned with prominent adolescent values. This suggests a route to an elusive result: effective motivation for adolescent behavior change.

Abstract

What can be done to reduce unhealthy eating among adolescents? It was hypothesized that aligning healthy eating with important and widely shared adolescent values would produce the needed motivation. A double-blind, randomized, placebo-controlled experiment with eighth graders (total n = 536) evaluated the impact of a treatment that framed healthy eating as consistent with the adolescent values of autonomy from adult control and the pursuit of social justice. Healthy eating was suggested as a way to take a stand against manipulative and unfair practices of the food industry, such as engineering junk food to make it addictive and marketing it to young children. Compared with traditional health education materials or to a non–food-related control, this treatment led eighth graders to see healthy eating as more autonomy-assertive and social justice-oriented behavior and to forgo sugary snacks and drinks in favor of healthier options a day later in an unrelated context. Public health interventions for adolescents may be more effective when they harness the motivational power of that group’s existing strongly held values.

Avalanche of Distrust

I keep returning to an Op-Ed piece by David Brooks, with the title of this post, in my queue of articles that are candidates for mention. Of Trump and Clinton he notes:

Both ultimately hew to a distrustful, stark, combative, zero-sum view of life — the idea that making it in this world is an unforgiving slog and that, given other people’s selfish natures, vulnerability is dangerous…

He continues:

...these nominees didn’t emerge in a vacuum. Distrustful politicians were nominated by an increasingly distrustful nation. A generation ago about half of all Americans felt they could trust the people around them, but now less than a third think other people are trustworthy. ..only about 19 percent of millennials believe other people can be trusted.

Over the past few decades, the decline in social trust has correlated to an epidemic of loneliness. In 1985, 10 percent of Americans said they had no close friend with whom they could discuss important matters. By 2004, 25 percent had no such friend.

...the pervasive atmosphere of distrust undermines actual intimacy, which involves progressive self-disclosure, vulnerability, emotional risk and spontaneous and unpredictable face-to-face conversations. Instead, what you see in social media is often the illusion of intimacy. The sharing is tightly curated — in a way carefully designed to mitigate unpredictability, danger, vulnerability and actual intimacy.

(As an aside, note this article on Beyonce as a model for how to survive social media.)
Continuing with Brooks:

…fear is the great enemy of intimacy. But the loss of intimacy makes society more isolated. Isolation leads to more fear. More fear leads to fear-mongering leaders…

The great religions and the wisest political philosophies have always counseled going the other way. They’ve always advised that real strength is found in comradeship, and there’s no possibility of that if you are building walls. They have generally championed the paradoxical leap — that even in the midst of an avalanche of calumny, somebody’s got to greet distrust with vulnerability, skepticism with innocence, cynicism with faith and hostility with affection.

Our candidates aren’t doing it, but that really is the realistic path to strength.

Decoding spontaneous emotional states in our brains.

Kragel et al. find distinctive patterns of brain activity that correspond to spontaneously experienced emotions in the absence of external emotional stimuli.  (Might this kind of work have the potential of giving us a scary ultimate lie detector test?) Their abstract and a summary figure:

Pattern classification of human brain activity provides unique insight into the neural underpinnings of diverse mental states. These multivariate tools have recently been used within the field of affective neuroscience to classify distributed patterns of brain activation evoked during emotion induction procedures. Here we assess whether neural models developed to discriminate among distinct emotion categories exhibit predictive validity in the absence of exteroceptive emotional stimulation. In two experiments, we show that spontaneous fluctuations in human resting-state brain activity can be decoded into categories of experience delineating unique emotional states that exhibit spatiotemporal coherence, covary with individual differences in mood and personality traits, and predict on-line, self-reported feelings. These findings validate objective, brain-based models of emotion and show how emotional states dynamically emerge from the activity of separable neural systems.

Figure - Distributed patterns of brain activity predict the experience of discrete emotions. (A) Parametric maps indicate brain regions in which increased fMRI signal informs the classification of emotional states. (B) Sensitivity of the seven models. Error bars depict 95% confidence intervals.

Science in the age of selfies

Some clips from an interesting opinion piece by Geman and Geman in the Proceedings of the National Academy:

These days, scientists spend much of their time taking “professional selfies”—effectively spending more time announcing ideas than formulating them.

The authors begin by contrasting the period from 1915 to 1965 with the subsequent 50 years. In the earlier period,

Life scientists discovered DNA, the genetic code, transcription, and examples of its regulation, yielding, among other insights, the central dogma of biology. Astronomers and astrophysicists found other galaxies and the signatures of the big bang. Groundbreaking inventions included the transistor, photolithography, and the printed circuit, as well as microwave and satellite communications and the practices of building computers, writing software, and storing data. Atomic scientists developed NMR and nuclear power. The theory of information appeared, as well as the formulation of finite state machines, universal computers, and a theory of formal grammars. Physicists extended the classical models with the theories of relativity, quantum mechanics, and quantum fields, while launching the standard model of elementary particles and conceiving the earliest versions of string theory.

Would a visitor from 1965, having traveled the 50 years to 2015, be equally dazzled?

Maybe not. Perhaps, though, the pace of technological development would have surprised most futurists, but the trajectory was at least partly foreseeable. This is not to deny that our time traveler would find the Internet, new medical imaging devices, advances in molecular biology and gene editing, the verification of gravity waves, and other inventions and discoveries remarkable, nor to deny that these developments often required leaps of imagination, deep mathematical analyses, and hard-earned technical know-how. Nevertheless, the advances are mostly incremental, and largely focused on newer and faster ways to gather and store information, communicate, or be entertained.

Here there is a paradox: Today, there are many more scientists, and much more money is spent on research, yet the pace of fundamental innovation, the kinds of theories and engineering practices that will feed the pipeline of future progress, appears, to some observers, including us, to be slowing

Cultural Shift

What has certainly changed, even drastically, is the day-to-day behavior of scientists, partly driven by new technology that affects everyone and partly driven by an alteration in the system of rewards and incentives...One outcome that might be quickly apparent to our time traveler would be the new mode of activity, “being online,” and how popular it is...most of us, but especially young people, are perpetually distracted by “messaging.” ..Constant external stimulation may inhibit deep thinking. In fact, is it even possible to think creatively while online? Perhaps “thinking out of the box” has become rare because the Internet is itself a box... Easy travel, many more meetings, relentless emails, and, in general, a low threshold for interaction have created a veritable epidemic of communication. Evolution relies on genetic drift and the creation of a diverse gene pool. Are ideas so different? Is there a risk of cognitive inbreeding? Communication is necessary, but, if there is too much communication, it starts to look like everyone is working in pretty much the same direction. A current example is the mass migration to “deep learning” in machine intelligence.

In fact, maybe it has become too easy to collaborate. Great ideas rarely come from teams...Science of the past 50 years seems to be more defined by big projects than by big ideas...It may not be a coincidence...that two of the most profound developments in mathematics in the current century—Grigori Perelman’s proof of the Poincaré conjecture and Yitang Zhang’s contributions to the twin-prime conjecture—were the work of iconoclasts with an instinct for solitude and, by all accounts, no particular interest in being “connected.” Prolonged focusing is getting harder. In the past, getting distracted required more effort. Writer Philip Roth predicts a negligible audience for novels (“maybe more people than now read Latin poetry, but somewhere in that range”) as they become too demanding of sustained attention in our new culture.

Daily Grind

...maybe the biggest change affecting scientists is their role as employees, and what they are paid for doing—in effect, the job description. In industry, there are few jobs for pure research and, despite initiatives at companies like Microsoft and Google, still no modern version of Bell Labs. At the top research universities, scientists are hired, paid, and promoted primarily based on their degree of exposure, often measured by the sheer size of the vita listing all publications, conferences attended or organized, talks given, proposals submitted or funded, and so forth...The response of the scientific community to the changing performance metrics has been entirely rational: We spend much of our time taking “professional selfies.” In fact, many of us spend more time announcing ideas than formulating them. Being busy needs to be visible, and deep thinking is not. Academia has largely become a small-idea factory. Rewarded for publishing more frequently, we search for “minimum publishable units.”...incentives for exploring truly novel ideas have practically disappeared.

Less Is More

Albert Einstein remarked that “an academic career, in which a person is forced to produce scientific writings in great amounts, creates a danger of intellectual superficiality”; the physicist Peter Higgs felt that he could not replicate his discovery of 1964 in today’s academic climate; and the neurophysiologist David Hubel observed that the climate that nurtured his remarkable 25-year collaboration with Torsten Wiesel, which began in the late 1950s and revealed the basic properties of the visual cortex, had all but disappeared by the early 1980s, replaced by intense competition for grants and pressure to publish. Looking back on the collaboration, he noted that “it was possible to take more long-shots without becoming panic stricken if things didn’t work out brilliantly in the first few months”

The authors end their article by suggesting one way of attempting to reverse the small idea factory:

Change the criteria for measuring performance. In essence, go back in time. Discard numerical performance metrics, which many believe have negative impacts on scientific inquiry. Suppose, instead, every hiring and promotion decision were mainly based on reviewing a small number of publications chosen by the candidate. The rational reaction would be to spend more time on each project, be less inclined to join large teams in small roles, and spend less time taking professional selfies. Perhaps we can then return to a culture of great ideas and great discoveries.

More great news: Our brains are polluted with environmental magnetite.

From Maher et al.:

Summary

We identify the abundant presence in the human brain of magnetite nanoparticles that match precisely the high-temperature magnetite nanospheres, formed by combustion and/or friction-derived heating, which are prolific in urban, airborne particulate matter (PM). Because many of the airborne magnetite pollution particles are less than 200 nm in diameter, they can enter the brain directly through the olfactory nerve and by crossing the damaged olfactory unit. This discovery is important because nanoscale magnetite can respond to external magnetic fields, and is toxic to the brain, being implicated in production of damaging reactive oxygen species (ROS). Because enhanced ROS production is causally linked to neurodegenerative diseases such as Alzheimer’s disease, exposure to such airborne PM-derived magnetite nanoparticles might need to be examined as a possible hazard to human health.

Abstract

Biologically formed nanoparticles of the strongly magnetic mineral, magnetite, were first detected in the human brain over 20 y ago [Kirschvink JL, Kobayashi-Kirschvink A, Woodford BJ (1992) Proc Natl Acad Sci USA 89(16):7683–7687]. Magnetite can have potentially large impacts on the brain due to its unique combination of redox activity, surface charge, and strongly magnetic behavior. We used magnetic analyses and electron microscopy to identify the abundant presence in the brain of magnetite nanoparticles that are consistent with high-temperature formation, suggesting, therefore, an external, not internal, source. Comprising a separate nanoparticle population from the euhedral particles ascribed to endogenous sources, these brain magnetites are often found with other transition metal nanoparticles, and they display rounded crystal morphologies and fused surface textures, reflecting crystallization upon cooling from an initially heated, iron-bearing source material. Such high-temperature magnetite nanospheres are ubiquitous and abundant in airborne particulate matter pollution. They arise as combustion-derived, iron-rich particles, often associated with other transition metal particles, which condense and/or oxidize upon airborne release. Those magnetite pollutant particles which are less than ∼200 nm in diameter can enter the brain directly via the olfactory bulb. Their presence proves that externally sourced iron-bearing nanoparticles, rather than their soluble compounds, can be transported directly into the brain, where they may pose hazard to human health.

Recollecting details improves future performance

Interesting work from Madore et al. on neural processes though which improving the quality of recalling details of the past enhances thinking about the future:

Recent behavioral work suggests that an episodic specificity induction—brief training in recollecting the details of a past experience—enhances performance on subsequent tasks that rely on episodic retrieval, including imagining future experiences, solving open-ended problems, and thinking creatively. Despite these far-reaching behavioral effects, nothing is known about the neural processes impacted by an episodic specificity induction. Related neuroimaging work has linked episodic retrieval with a core network of brain regions that supports imagining future experiences. We tested the hypothesis that key structures in this network are influenced by the specificity induction. Participants received the specificity induction or one of two control inductions and then generated future events and semantic object comparisons during fMRI scanning. After receiving the specificity induction compared with the control, participants exhibited significantly more activity in several core network regions during the construction of imagined events over object comparisons, including the left anterior hippocampus, right inferior parietal lobule, right posterior cingulate cortex, and right ventral precuneus. Induction-related differences in the episodic detail of imagined events significantly modulated induction-related differences in the construction of imagined events in the left anterior hippocampus and right inferior parietal lobule. Resting-state functional connectivity analyses with hippocampal and inferior parietal lobule seed regions and the rest of the brain also revealed significantly stronger core network coupling following the specificity induction compared with the control. These findings provide evidence that an episodic specificity induction selectively targets episodic processes that are commonly linked to key core network regions, including the hippocampus.

Insight into intergroup conflict - defense trumps aggression

A fascinating piece from De Dreu et al. who devise a simple contest game whose results suggest that in inter-groups conflicts in-group defense is more effective that out-group aggression.  A clip from their introductory comments, followed by their abstact:

From group-hunting by lions, wolves, or killer whales, to groups of chimpanzees raiding their neighbors, to hostile takeovers in the marketplace, and to territorial conflicts within and between nation states, intergroup conflict is often a clash between the antagonist’s out-group aggression and the opponent’s in-group defense.... In-group defense and out-group aggression appear to have distinct neurobiological origins, and may thus recruit different within-group dynamics. Whereas self-defense is impulsive and relies on brain structures involved in threat signaling and emotion regulation, offensive aggression is more instrumental and conditioned by executive control.... the motivation to avoid loss is stronger than the search for gain, suggesting that individuals more readily contribute to defensive, rather than offensive, aggression. Finally, self-sacrifice in combat is publicly rewarded more (e.g., with a Medal of Honor) when it served in-group defense rather than out-group aggression. Accordingly, in-group defense may emerge more spontaneously, and individuals may be more intrinsically motivated to contribute to in-group defense than to out-group aggression.

Significance

Across a range of domains, from group-hunting predators to laboratory groups, companies, and nation states, we find that out-group aggression is less successful because it is more difficult to coordinate than in-group defense. This finding explains why appeals for defending the in-group may be more persuasive than appeals to aggress a rivaling out-group and suggests that (third) parties seeking to regulate intergroup conflict should, in addition to reducing willingness to contribute to one’s group’s fighting capacity, undermine arrangements for coordinating out-group aggression, such as leadership, communication, and infrastructure.

Abstract

Intergroup conflict persists when and because individuals make costly contributions to their group’s fighting capacity, but how groups organize contributions into effective collective action remains poorly understood. Here we distinguish between contributions aimed at subordinating out-groups (out-group aggression) from those aimed at defending the in-group against possible out-group aggression (in-group defense). We conducted two experiments in which three-person aggressor groups confronted three-person defender groups in a multiround contest game (n = 276; 92 aggressor–defender contests). Individuals received an endowment from which they could contribute to their group’s fighting capacity. Contributions were always wasted, but when the aggressor group’s fighting capacity exceeded that of the defender group, the aggressor group acquired the defender group’s remaining resources (otherwise, individuals on both sides were left with the remainders of their endowment). In-group defense appeared stronger and better coordinated than out-group aggression, and defender groups survived roughly 70% of the attacks. This low success rate for aggressor groups mirrored that of group-hunting predators such as wolves and chimpanzees (n = 1,382 cases), hostile takeovers in industry (n = 1,637 cases), and interstate conflicts (n = 2,586). Furthermore, whereas peer punishment increased out-group aggression more than in-group defense without affecting success rates (Exp. 1), sequential (vs. simultaneous) decision-making increased coordination of collective action for out-group aggression, doubling the aggressor’s success rate (Exp. 2). The relatively high success rate of in-group defense suggests evolutionary and cultural pressures may have favored capacities for cooperation and coordination when the group goal is to defend, rather than to expand, dominate, and exploit.

Election Stress Disorder

If not already, and certainly after last night's presidential election debate between Donald Trump and Hillary Clinton, I suspect you have joined me in suffering full blown "Election Stress Disorder" - by now a syndrome worthy of inclusion in the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition). Linda Bolt does a piece in SALON on the po litical anxiety and fear that used to be a health problem only in the developing world. Some clips:

Steven Stosny, Ph.D, author of “Soar Above: How to Use the Most Profound Part of Your Brain Under Any Kind of Stress,“ recently identified a phenomenon he dubbed “Election Stress Disorder” ...“This election appeals more to the toddler brain — emotional, all-or-nothing thinking — with more of the toddler coping mechanisms: blame, denial, and avoidance. The body can’t distinguish kinds of stress very well, especially when blame, denial, and avoidance are used as coping mechanisms. If you get peeved at something a candidate says, you’ll tend to look for oversimplified solutions at work, drink more, drive more aggressively, and suffer the physiological and mental effects of general stress.”

Stephen Holland, the director of the the Capital Institute of Cognitive Therapy in Washington, D.C., recently told The Atlantic that “probably two-thirds to three-quarters of our patients are mentioning their feelings about the election in session.” For many, those feelings are related to one candidate in particular...

Stress caused by election fatigue isn’t a new, or even uniquely American phenomenon — most previous documented cases come from politically unstable developing countries. In Thailand during a 2014 military coup and resulting social media controversy, the Public Health Ministry warned citizens that consuming too much news media could be harmful to mental health

It’s clear that all this stress is not only taking a demonstrable toll on the public’s well-being, but it could also affect the election itself. A 2014 study published in the journal Physiology and Behavior found that individuals with higher concentrations of the stress hormone cortisol were actually less likely to vote (regardless of which party they supported) — which means those experiencing severe anxiety over a Trump presidency might actually help make it a reality if they don’t make it out to the polls.

So, is there any remedy for Election Stress Syndrome? Stosny recommends voters try to shift to the adult brain and “hold other people’s perspectives alongside your own. Weigh evidence, see nuance, plan for the future and replace blame, denial, and avoidance with appreciation of complexity.” Of course, that won’t stop a large number of people from obsessively Googling “how to move to Canada.”

A hedonism hub in the human brain.

A open source article from Zacharopoulos et al., who have found that people who rate hedonism as more important in their life have a larger globus pallidus (GP) in their left hemisphere:

Human values are abstract ideals that motivate behavior. The motivational nature of human values raises the possibility that they might be underpinned by brain structures that are particularly involved in motivated behavior and reward processing. We hypothesized that variation in subcortical hubs of the reward system and their main connecting pathway, the superolateral medial forebrain bundle (slMFB) is associated with individual value orientation. We conducted Pearson's correlation between the scores of 10 human values and the volumes of 14 subcortical structures and microstructural properties of the medial forebrain bundle in a sample of 87 participants, correcting for multiple comparisons (i.e.,190). We found a positive association between the value that people attach to hedonism and the volume of the left globus pallidus (GP).We then tested whether microstructural parameters (i.e., fractional anisotropy and myelin volume fraction) of the slMFB, which connects with the GP, are also associated to hedonism and found a significant, albeit in an uncorrected level, positive association between the myelin volume fraction within the left slMFB and hedonism scores. This is the first study to elucidate the relationship between the importance people attach to the human value of hedonism and structural variation in reward-related subcortical brain regions.

Dreams and revelations.

I want to pass on a few clips from an engaging essay by Patrick McNamara, and suggest you read the entire piece. He begins by noting religious movements that trace their origins to dreams of their founders, and then notes:

 ...most people from across most cultures and all of history have treated dreams as direct evidence of a spirit realm. And that raises an obvious question: what is it about dreams that make them such potent vehicles for the supernatural? 

We know that rapid eye movement sleep (REM), when eyes move rapidly back and forth under closed eyelids, is the phase when we have the most vivid dreams. REM is associated with heightened levels of the neurotransmitters dopamine (associated with reward and movement) and acetylcholine (associated with memory), as well as a surge of activity in the limbic system, the amygdala, and the ventromedial prefrontal cortex, all areas of the brain that handle emotion. Conversely, there is lowered activity in the dorsolateral prefrontal cortex, the area of the brain that handles personal insight, rationality and judgement; likewise, the neurochemicals noradrenaline and serotonin, involved in vigilance and self-control, are regulated down. The very low levels of serotonin allow steady release of the excitatory transmitter glutamate, which overstimulates the brain activity thought to underlie the cognitive and perceptual effects of hallucinogens. In other words, in REM sleep, our emotional centres are overstimulated while our reflective rational centres are impeded or narrowly refocused on issues of emotional significance. We are left free to ponder the endless meanings of the emotions and interactions that we experience but we do so with wildly fluctuating levels of reflective insight.

It only makes sense that these REM-related brain changes are also associated with schizophrenia and the high of hallucinogenic drugs such as LSD. REM, schizophrenia and hallucinogens are all associated with the neurologic conditions that produce altered states of consciousness. The neurochemistry of dreams produces an emotionally intense state of mind in the absence of an ability to critically reflect on the images produced by that state. When the hallucinatory REM dream or an acid trip ends, individuals can then reflect on and attempt to interpret the intense experiences they’ve just undergone…The greater the interpretive difficulty, the more significance we impute to the experience – up to a point. That might explain why schizophrenics with positive hallucinations – including visual hallucinations, hearing voices, and delusions – report such high levels of religiosity, attempting to interpret their aberrant experiences through religious symbols, language and tropes.

Where does all this leave us today? On one hand, the link between REM dreams and spiritual experience disturbs some religious people because they fear it suggests that religion is nothing but delusional dreaming and hallucinations. On the other hand, the connection upsets some die-hard atheists, who dislike the idea that spirituality is rooted in our biology – that it is functional and adaptive, and central to who we are. 

What we do with the demonstration that spirituality is rooted in REM sleep and dreams is a personal – perhaps spiritual – choice. But science and society itself would benefit from taking the connection seriously. If our dreams generate spiritual ideas, they might also contribute to a generation of religious-based terrorism and fanaticism. After all, REM sleep has been studied as a model for psychosis. The same chemical brew that produces the dream state can, if tweaked, produce obsessional psychoses and related neuropsychiatric symptoms. Religious fanaticism has a kind of obsessional and paranoid feel to it that links it with REM intrusion into waking life and the subsequent delusional states that follow. The future neuroscience of the spiritual, rooted in the study of dreams, could help us to confront some of our era’s greatest challenges.

Treating trans-generational stress with probiotics...

There is considerable evidence that the effects of stress can be transmitted across multiple generations in rats and also humans. Studies suggest that such inheritance might be intergenerational (mating behavior, parenting, in utero effects, etc.) or transgenerational (e.g., germ-line epigenetic alteration).

Given that gastrointestinal disorders frequently occur alongside various forms of psychopathology, and that their prevalence is increased in populations exposed to early-life stress, Callaghan et al. have now done experiments on rats suggesting that stress-induced changes to gut microbiota may play a mechanistic role (via microbiota-gut-brain interactions) in the transmission of stress reactivity across generations, and that probiotics can ameliorate this effect.

Early-life adversity is a potent risk factor for mental-health disorders in exposed individuals, and effects of adversity are exhibited across generations. Such adversities are also associated with poor gastrointestinal outcomes. In addition, emerging evidence suggests that microbiota-gut-brain interactions may mediate the effects of early-life stress on psychological dysfunction. In the present study, we administered an early-life stressor (i.e., maternal separation) to infant male rats, and we investigated the effects of this stressor on conditioned aversive reactions in the rats’ subsequent infant male offspring. We demonstrated, for the first time, longer-lasting aversive associations and greater relapse after extinction in the offspring (F1 generation) of rats exposed to maternal separation (F0 generation), compared with the offspring of rats not exposed to maternal separation. These generational effects were reversed by probiotic supplementation, which was effective as both an active treatment when administered to infant F1 rats and as a prophylactic when administered to F0 fathers before conception (i.e., in fathers’ infancy). These findings have high clinical relevance in the identification of early-emerging putative risk phenotypes across generations and of potential therapies to ameliorate such generational effects.

Biofeedback to chill out your amygdala’s hyper-reactivity?

Tyler McDonald in NewAtlas points to this interesting collaboration of a group of Tel-Aviv university neuroscientists that suggests the possibility that a new generation of EEG feedback devices might allow regulating of unwanted behaviors, making psychotropic drugs less necessary:

The amygdala has a pivotal role in processing traumatic stress; hence, gaining control over its activity could facilitate adaptive mechanism and recovery. To date, amygdala volitional regulation could be obtained only via real-time functional magnetic resonance imaging (fMRI), a highly inaccessible procedure. The current article presents high-impact neurobehavioral implications of a novel imaging approach that enables bedside monitoring of amygdala activity using fMRI-inspired electroencephalography (EEG), hereafter termed amygdala-electrical fingerprint (amyg-EFP). Simultaneous EEG/fMRI indicated that the amyg-EFP reliably predicts amygdala-blood oxygen level–dependent activity. Implementing the amyg-EFP in neurofeedback demonstrated that learned downregulation of the amyg-EFP facilitated volitional downregulation of amygdala-blood oxygen level–dependent activity via real-time fMRI and manifested as reduced amygdala reactivity to visual stimuli. Behavioral evidence further emphasized the therapeutic potential of this approach by showing improved implicit emotion regulation following amyg-EFP neurofeedback. Additional EFP models denoting different brain regions could provide a library of localized activity for low-cost and highly accessible brain-based diagnosis and treatment.

Scientific studies show....

I have to pass on one more of John Oliver's skewerings of what comes at us every day. It is an expanded version of the sort of material that was in last Thursday's post.

Defining brain areas involved in music perception.

From Sihvonen et al:

Although acquired amusia is a relatively common disorder after stroke, its precise neuroanatomical basis is still unknown. To evaluate which brain regions form the neural substrate for acquired amusia and its recovery, we performed a voxel-based lesion-symptom mapping (VLSM) and morphometry (VBM) study with 77 human stroke subjects. Structural MRIs were acquired at acute and 6 month poststroke stages. Amusia and aphasia were behaviorally assessed at acute and 3 month poststroke stages using the Scale and Rhythm subtests of the Montreal Battery of Evaluation of Amusia (MBEA) and language tests. VLSM analyses indicated that amusia was associated with a lesion area comprising the superior temporal gyrus, Heschl's gyrus, insula, and striatum in the right hemisphere, clearly different from the lesion pattern associated with aphasia. Parametric analyses of MBEA Pitch and Rhythm scores showed extensive lesion overlap in the right striatum, as well as in the right Heschl's gyrus and superior temporal gyrus. Lesions associated with Rhythm scores extended more superiorly and posterolaterally. VBM analysis of volume changes from the acute to the 6 month stage showed a clear decrease in gray matter volume in the right superior and middle temporal gyri in nonrecovered amusic patients compared with nonamusic patients. This increased atrophy was more evident in anterior temporal areas in rhythm amusia and in posterior temporal and temporoparietal areas in pitch amusia. Overall, the results implicate right temporal and subcortical regions as the crucial neural substrate for acquired amusia and highlight the importance of different temporal lobe regions for the recovery of amusia after stroke.

Predicting false memories with fMRI

Chadwick et al. find that the the apex of the ventral processing stream in the brain's temporal pole (TP) contains partially overlapping neural representations of related concepts, and that the extent of this neural overlap directly reflects the degree of semantic similarity between the concepts. Furthermore, the neural overlap between sets of related words predicts the likelihood of making a false-memory error. (One could wonder if further development of work of this sort might make it possible to perform an fMRI evaluation of an eye witness in an important trial to determine whether their testimony is more or less likely to be correct.)

Significance

False memories can arise in daily life through a mixture of factors, including misinformation and prior conceptual knowledge. This can have serious consequences in settings, such as legal eyewitness testimony, which depend on the accuracy of memory. We investigated the brain basis of false memory with fMRI, and found that patterns of activity in the temporal pole region of the brain can predict false memories. Furthermore, we show that each individual has unique patterns of brain activation that can predict their own idiosyncratic set of false-memory errors. Together, these results suggest that the temporal pole may be responsible for the conceptual component of illusory memories.

Abstract

Recent advances in neuroscience have given us unprecedented insight into the neural mechanisms of false memory, showing that artificial memories can be inserted into the memory cells of the hippocampus in a way that is indistinguishable from true memories. However, this alone is not enough to explain how false memories can arise naturally in the course of our daily lives. Cognitive psychology has demonstrated that many instances of false memory, both in the laboratory and the real world, can be attributed to semantic interference. Whereas previous studies have found that a diverse set of regions show some involvement in semantic false memory, none have revealed the nature of the semantic representations underpinning the phenomenon. Here we use fMRI with representational similarity analysis to search for a neural code consistent with semantic false memory. We find clear evidence that false memories emerge from a similarity-based neural code in the temporal pole, a region that has been called the “semantic hub” of the brain. We further show that each individual has a partially unique semantic code within the temporal pole, and this unique code can predict idiosyncratic patterns of memory errors. Finally, we show that the same neural code can also predict variation in true-memory performance, consistent with an adaptive perspective on false memory. Taken together, our findings reveal the underlying structure of neural representations of semantic knowledge, and how this semantic structure can both enhance and distort our memories.

Self-regulation via neural simulation

A fascinating study from Gilead et al.:

Significance

As Harper Lee tells us in To Kill a Mockingbird, “You never really understand a person until you consider things from his point of view, until you climb in his skin and walk around in it.” Classic theories in social psychology argue that this purported process of social simulation provides the foundations for self-regulation. In light of this, we investigated the neural processes whereby humans may regulate their affective responses to an event by simulating the way others would respond to it. Our results suggest that during perspective-taking, behavioral and neural signatures of negative affect indeed mimic the presumed affective state of others. Furthermore, the anterior medial prefrontal cortex—a region implicated in mental state inference—may orchestrate this affective simulation process.

Abstract

Can taking the perspective of other people modify our own affective responses to stimuli? To address this question, we examined the neurobiological mechanisms supporting the ability to take another person’s perspective and thereby emotionally experience the world as they would. We measured participants’ neural activity as they attempted to predict the emotional responses of two individuals that differed in terms of their proneness to experience negative affect. Results showed that behavioral and neural signatures of negative affect (amygdala activity and a distributed multivoxel pattern reflecting affective negativity) simulated the presumed affective state of the target person. Furthermore, the anterior medial prefrontal cortex (mPFC)—a region implicated in mental state inference—exhibited a perspective-dependent pattern of connectivity with the amygdala, and the multivoxel pattern of activity within the mPFC differentiated between the two targets. We discuss the implications of these findings for research on perspective-taking and self-regulation.

A psychological mechanism to explain why childhood adversity diminishes adult health?

A large number of studies have by now shown that harsh social and physical environments early in life are associated with a substantial increase in the risk of chronic illnesses, such as heart disease, diabetes, and some forms of cancer. It is generally assumed that the hypothalamic-pituitary-adrenal (HPA) axis is an essential biological intermediary of these poor health outcomes in adulthood. Zilioli et al. suggest that lowered sense of self worth is the psychological mechanism that persists into adulthood to alter stress physiology. Their abstract:

Childhood adversity is associated with poor health outcomes in adulthood; the hypothalamic-pituitary-adrenal (HPA) axis has been proposed as a crucial biological intermediary of these long-term effects. Here, we tested whether childhood adversity was associated with diurnal cortisol parameters and whether this link was partially explained by self-esteem. In both adults and youths, childhood adversity was associated with lower levels of cortisol at awakening, and this association was partially driven by low self-esteem. Further, we found a significant indirect pathway through which greater adversity during childhood was linked to a flatter cortisol slope via self-esteem. Finally, youths who had a caregiver with high self-esteem experienced a steeper decline in cortisol throughout the day compared with youths whose caregiver reported low self-esteem. We conclude that self-esteem is a plausible psychological mechanism through which childhood adversity may get embedded in the activity of the HPA axis across the life span.

And, a clip from their discussion, noting limits to the interpretation of the correlations they observe:

These findings suggest that one’s sense of self-worth might act as a proximal psychological mechanism through which childhood adversity gets embedded in human stress physiology. Specifically, higher self-esteem was associated with a steeper (i.e., healthier) cortisol decline during the day, whereas low self-esteem was associated with a flatter cortisol slope. Depression and neuroticism were tested as alternative pathways linking childhood adversity to cortisol secretion and were found not to be significant, which suggests that the indirect effect was specific to self-esteem. Nevertheless, it is plausible that other psychological pathways exist that might carry the effects of childhood adversity across the life span. For example, attachment security, a potential antecedent of self-esteem that forms during childhood, would be a strong candidate for playing such a role. Unfortunately, this construct was not assessed in our studies, but we hope that future work will test this hypothesis.