Our nervous systems are lazy.

Selinger et al. show that the subconscious nervous processes that regulate our movement are constantly adapting to minimize the energy required for movement in a given situation. To show this, they had subjects wear robotic exoskeletons that could increase or decrease resistance to the knees, to change the difficulty of swinging the legs during walking. Within minutes, gate was adjusted to be energetically more optimal.

Highlights

•People readily adapt established gait patterns to minimize energy use 

•People converge on new energetic optima within minutes, even for small cost savings 

•Updated predictions about energetically optimal gaits allow re-convergence within seconds 

•Energetic cost is not just an outcome of movement, but also continuously shapes it

Summary

People prefer to move in ways that minimize their energetic cost. For example, people tend to walk at a speed that minimizes energy use per unit distance and, for that speed, they select a step frequency that makes walking less costly. Although aspects of this preference appear to be established over both evolutionary and developmental timescales, it remains unclear whether people can also optimize energetic cost in real time. Here we show that during walking, people readily adapt established motor programs to minimize energy use. To accomplish this, we used robotic exoskeletons to shift people’s energetically optimal step frequency to frequencies higher and lower than normally preferred. In response, we found that subjects adapted their step frequency to converge on the new energetic optima within minutes and in response to relatively small savings in cost (less than 5%). When transiently perturbed from their new optimal gait, subjects relied on an updated prediction to rapidly re-converge within seconds. Our collective findings indicate that energetic cost is not just an outcome of movement, but also plays a central role in continuously shaping it.

The social mysteries of the superior temporal sulcus

Michael Beauchamp does a summary of work by Deen et al. (open access), who use functional magnetic resonance imaging (fMRI) to show a regular anterior–posterior organization in the STS for different social tasks such as theory of mind, biological motion, faces, voices and language. Here is the summary graphic:

Organization of social perception and cognition within the superior temporal sulcus (STS). Results of Deen et al. are shown on an inflated cortical surface model of the left and right hemisphere. Filled circles show the location of the peak activation, averaged across subjects, for each contrast. Colored regions show the extent of the activation for each contrast (multiple colored regions for some contrasts). 

A final musical/social at Twin Valley - some Rachmaninoff

A personal posting: On Sunday Sept. 13, Len and I hosted our last musical/social at the 1860 stone school house we have lived in for 25 years (I have been doing affairs like these since 1971-72). The following Wednesday, the Steinway B left for our Fort Lauderdale condo. The school house will be offered for sale in the spring of 2016, as we contract our Madison WI footprint to a condo near the university campus. Good friend Roy Wesley did video recordings of the concert, using a simple camera whose automatic volume control for audio damped out dynamic volume changes. I've posted these on YouTube, commentary and glitches included, just to have a record for myself and a few friends. I thought I would pass on the concert program, some pictures, an embedded video of the final Rachmaninoff  pieces, and URLS of the others, to MindBlog readers.

Program 

Chopin Nocturne in C# minor No. 18 (post.), Trois Ecossaises Op. 72 (post.) No. 3 

J. Brahms Capriccio Op 76. No 2; Waltzes, Op. 39 Nos.1, 12, 13, 14, 15. 

C. Debussy - Preludes Livre I - Danseuse de Delphes, Minstrels , Les Collines d’Anacapri 

F. Poulenc - Valse, Improvisation No. 14, Nocturne No. 2 

S.  Rachmaninoff Morceaux de fantasie (Fantasy pieces) Op. 3, No. 1, Elegie; No. 4, Polichinelle

Here is a video of the Rachmaninoff:

And URLs:
J. Brahms Capriccio Op 76. No 2; Waltzes, Op. 39 Nos.1, 12, 13, 14, 15
C. Debussy - Preludes Livre I - Danseuse de Delphes, Minstrels , Les Collines d’Anacapri 
F. Poulenc - Valse, Improvisation No. 14, Nocturne No. 2 

Hormones and clothing choices.

Here is an interesting and curious bit from Eisenbruch et al.:

Recent evidence supports the idea that women use red clothing as a courtship tactic, and results from one study further suggested that women were more likely to wear red on days of high fertility in their menstrual cycles. Subsequent studies provided mixed support for the cycle-phase effect, although all such studies relied on counting methods of cycle-phase estimation and used between-subjects designs. By comparison, in the study reported here, we employed frequent hormone sampling to more accurately assess ovulatory timing and used a within-subjects design. We found that women were more likely to wear red during the fertile window than on other cycle days. Furthermore, within-subjects fluctuations in the ratio of estradiol to progesterone statistically mediated the within-subjects shifts in red-clothing choices. Our results appear to represent the first direct demonstration of specific hormone measurements predicting observable changes in women’s courtship-related behaviors. We also demonstrate the advantages of hormonal determination of ovulatory timing for tests of cycle-phase shifts in psychology or behavior.

Heritable risk of developing anxiety correlates with brain metabolism, not structure.

A group of Univ. of Wisconsin collaborators adds another installment to their series of articles on anxiety in a primate model for humans.

Significance

According to the World Health Organization, anxiety and depressive disorders are a leading source of disability, affecting hundreds of millions of people. Children can inherit an extremely anxious temperament, which is a prominent risk factor for the later development of anxiety, depression, and comorbid substance abuse. This study uses high-resolution functional and structural imaging in our well-established developmental nonhuman primate model to identify the heritable neural substrate that underlies extreme childhood anxious temperament. Using a large multigenerational family pedigree, genetic correlation analyses revealed a tripartite neural circuit where metabolism likely shares a genetic substrate with early-life dispositional anxiety. Interestingly, we found that brain function—not structure—is the critical intermediary between genetics and the childhood risk to develop stress-related psychopathology.

Abstract

Understanding the heritability of neural systems linked to psychopathology is not sufficient to implicate them as intergenerational neural mediators. By closely examining how individual differences in neural phenotypes and psychopathology cosegregate as they fall through the family tree, we can identify the brain systems that underlie the parent-to-child transmission of psychopathology. Although research has identified genes and neural circuits that contribute to the risk of developing anxiety and depression, the specific neural systems that mediate the inborn risk for these debilitating disorders remain unknown. In a sample of 592 young rhesus monkeys that are part of an extended multigenerational pedigree, we demonstrate that metabolism within a tripartite prefrontal-limbic-midbrain circuit mediates some of the inborn risk for developing anxiety and depression. Importantly, although brain volume is highly heritable early in life, it is brain metabolism—not brain structure—that is the critical intermediary between genetics and the childhood risk to develop stress-related psychopathology.

Inventing new words - iconic sounds are used.

Perlman and collaborators find that students inventing new words use certain types of vocalizations with certain words. For example, made-up words for “up” have a rising pitch, words for “down” have a falling pitch. “Slow” has a long duration and a low pitch, whereas “fast” has a short duration and high pitch. And “smooth” has a high degree of harmonicity, whereas “rough” has a high degree of the opposite quality—noise. This suggests that vocal communication systems can originate from spontaneously created iconic characteristics of sound, just as gestural communication systems can originate from spontaneously created iconic gestures. The chart shows the data describing characteristics of words invented for 18 contrasting ideas: up, down, big, small, good, bad, fast, slow, far, near, few, many, long, short, rough, smooth, attractive, and ugly.

The plots show the acoustic characteristics of each of the 18 meanings. The five variables are represented on the x-axis: D, duration; H, harmonics to noise ratio; I, intensity; P, pitch; C, pitch change. All values are normalized (z-scored) for each of the five measures. The red line shows the median and the blue box spans the first and third quartiles. The up and down arrows indicate variables that differed reliably between antonymic meanings. For example, vocalizations for bad differed from those for good by having a lower harmonics to noise ratio and pitch. The variables marked with arrows were the basis for the iconic template of each meaning.

Brain correlates of learning character traits versus rewards.

Hsu and Jenkins summarize work of Hackel et al. showing where our brains learn about traits versus rewards.

In a functional magnetic resonance imaging (fMRI) study..., Hackel et al use an innovative combination of ideas and tools from social psychology, economics and cognitive neuroscience, they offer neural evidence that associative learning processes are involved in making inferences about traits. Specifically, the authors conducted a study in which participants interacted repeatedly with eight different partners: four purported human participants and four slot machines. On each trial, participants chose to interact with one of two human (or slot machine) counterparts. The chosen counterpart, who had been endowed with a certain number of points on that trial, then shared some proportion of those points with the participant. Critically, targets varied orthogonally in terms of the average magnitude of their starting endowment (reward) and the average proportion of the endowment that was shared with the participant (generosity), enabling the authors to dissociate signals associated with trait learning from those associated with reward processing.

Consistent with the idea that trait learning engages associative learning processes, BOLD (blood oxygen level-dependent) responses of the ventral striatum during an initial training phase were predicted by an associative learning model that captures both reward and trait information. Moreover, two pieces of evidence support the idea that participants were able to make use of this trait information in a manner described by psychological theories of trait attribution. First, in a test phase in which participants knew each potential partner's starting endowment, participants chose interaction partners on the basis of those partners' past levels of generosity, and the extent to which they did so was associated with activity in the ventromedial prefrontal cortex (see figure). In addition, participants exhibited a tendency to generalize these generosity attributions, preferring the more generous targets when asked to pick a collaborator for a new, cooperative task-a hallmark of trait attribution.

Figure: Learning about traits versus rewards.  In an fMRI study, participants interacted with partners who varied in reward (the absolute amount of money shared with the participant) and generosity (the proportion shared). Activity in the ventromedial prefrontal cortex (vmPFC) was associated with preferring more generous targets, even when those targets shared less money in absolute terms.

Thinking too much - Self generated thought as the engine of neuroticism.

Perkins et al. offer an opinion piece in which they propose that the cost and benefits of neuroticism are surface manifestations of a tendency to engage in negatively hued self generated thought. I pass on their abstract and text from one of their figures:

•Existing neuroticism models cannot explain its link to both unhappiness and creativity. 

•Self-generated thought (SGT) facilitates creativity but can cause unhappiness. 

•Threat-related regions of medial prefrontal cortex (mPFC) generate blue-tinted SGT. 

•High neuroticism may reflect proneness to SGT arising from mPFC hyperactivity. 

Neuroticism is a dimension of personality that captures trait individual differences in the tendency to experience negative thoughts and feelings. Established theories explain neuroticism in terms of threat sensitivity, but have limited heuristic value since they cannot account for features of neuroticism that are unrelated to threat, such as creativity and negative psychological states experienced in benign, threat-free environments. We address this issue by proposing that neuroticism stems from trait individual differences in activity in brain circuits that govern the nature of self-generated thought (SGT). We argue our theory explains not only the association of neuroticism with threat sensitivity but also the prominence within the neurotic mind of representations of information that are unrelated to the way the world is right now, such as creativity and nonsituational ‘angst’.

A figure legend from the text (graphics did not have resolution adequate to display here):

Neuroticism, self-generated thought (SGT) and perceptions of threat intensity. (A) If an individual with ventromedial prefrontal cortex (vmPFC)/basolateral nuclei of the amygdala (BLA) that is twice as reactive as that of the average person switches from anxiety to panic when a spider encroaches within 4 m (an early switcher), then an average person will switch from anxiety to panic only when that same spider encroaches within 2 m (an ‘average switcher’). Conversely, a person with vmPFC/BLA that is half as reactive as that of the average person will switch from anxiety to panic only when that same spider encroaches within 1 m (a ‘late switcher’). The same psychological state (panic) is achieved in each individual, but the physical distance to threat that elicits it is different. (The graphic showed approaching spider.)(B) A model of how neuroticism is driven by individual differences in susceptibility to negatively hued SGT. Individuals who happen to have greater spontaneous activity in regions of mPFC associated with threat perception, experience frequent, spontaneous activation of threat-related amygdala circuits in situations that are wholly nonthreatening. (The graphic was picture of flowers.) In individuals who also happen to have a highly reactive vmPFC/BLA, these activations are likely to be sufficiently intense to be debilitating; therefore, such individuals present as being highly neurotic.

Savoring happy memories - value representations in the striatum

Speer et al. observe responses in the corticostriatal circuits that respond to monetary reward when positive autobiographical memories are recalled. These response "may be adaptive for regulating positive emotion and promoting better well-being."

Highlights 

•The act of recalling positive life events enhances emotion and has tangible value
•Corticostriatal fMRI signals index emotion evoked by recalling positive life events
•Striatal activity relates to positive mood enhancing effects of reminiscing
•Striatal responses to positive memories may relate to individual resilience 

Summary 

Reminders of happy memories can bring back pleasant feelings tied to the original experience, suggesting an intrinsic value in reminiscing about the positive past. However, the neural circuitry underlying the rewarding aspects of autobiographical memory is poorly understood. Using fMRI, we observed enhanced activity during the recall of positive relative to neutral autobiographical memories in corticostriatal circuits that also responded to monetary reward. Enhanced activity in the striatum and medial prefrontal cortex was associated with increases in positive emotion during recall, and striatal engagement further correlated with individual measures of resiliency. Striatal response to the recall of positive memories was greater in individuals whose mood improved after the task. Notably, participants were willing to sacrifice a more tangible reward, money, in order to reminisce about positive past experiences. Our findings suggest that recalling positive autobiographical memories is intrinsically valuable, which may be adaptive for regulating positive emotion and promoting better well-being.

Convergent evolution of numerosity detection in bird and primate brains.

From Ditz and Nieder:

Birds are known for their advanced numerical competence, although a six-layered neocortex that is thought to enable primates with the highest levels of cognition is lacking in birds. We recorded neuronal activity from an endbrain association area termed nidopallium caudolaterale (NCL) in crows that discriminated the number of items in displays. NCL neurons were tuned to preferred numerosities. Neuronal discharges were relevant for the crows’ correct performance. Both the neuronal and the behavioral tuning functions were best described on a logarithmic number line, just as predicted by the psychophysical Weber–Fecher Law. The behavioral and neuronal numerosity representations in the crow reflect surprisingly well those found in the primate association cortex. This finding suggests that distantly related vertebrates with independently developed endbrains adopted similar neuronal solutions to process quantity - convergent evolution of a superior solution to a common computational problem.

A classification of cognitive mechanisms in meditation practice.

Dahl, Lutz, and Davidson offer an interesting classification system for different styles of meditation. Here is a paste up from their abstract and introduction:

Scientific research highlights the central role of specific psychological processes, in particular those related to the self, in various forms of human suffering and flourishing. This view is shared by Buddhism and other contemplative and humanistic traditions, which have developed meditation practices to regulate these processes. Building on a previous paper in this journal, we propose a novel classification system that categorizes specific styles of meditation into attentional, constructive, and deconstructive families based on their primary cognitive mechanisms. According to this model, the primary cognitive mechanisms in these three families are: (i) attention regulation and meta-awareness; (ii) perspective taking and reappraisal; and (iii) self-inquiry, respectively. To illustrate the role of these processes in different forms of meditation, we discuss how experiential fusion, maladaptive self-schema, and cognitive reification are differentially targeted by these processes in the context of Buddhist meditation, integrating the perspectives of other contemplative, philosophical, and clinical perspectives when relevant. The mechanisms and targets we propose are drawn from cognitive science and clinical psychology. Although these psychological processes are theoretically complex, as are the meditation practices that target them, we propose this novel framework as a first step in identifying specific cognitive mechanisms to aid in the scientific study of different families of meditation and the impact of these practices on well-being.

This article appears to be open source, and well worth reading for those interested in meditation. (I can send full text to motivated readers who have difficulty securing the full text.) I thought I would pass on just one edited clip from the section on the constructive family of meditation practices:

One of the most widely studied practices in the constructive family is the cultivation of compassion. Compassion training is held to alter core self-related processes, initiating a shift from self-oriented cognitive, affective, and behavioral patterns to patterns that are oriented toward the well-being of others...Research into the neural correlates of empathy has found that similar regions, including the insula, the anterior and mid-cingulate cortices, and the supplementary motor area, are activated across various forms of empathy...By way of contrast, compassion is linked to regions associated with reward, positive affect, and feelings of affection, such as the ventral striatum and medial orbitofrontal cortex...Studies of compassion training have also found increased activation in regions associated with executive function, including the dorsolateral prefrontal cortex and the anterior cingulate cortex...these preliminary findings suggest that cultivating compassion strengthens multiple networks, each of which may affect distinct psychological processes and thereby contribute to well-being in different ways.

Empathy and compassion also affect the peripheral biology of the human body. Perceiving stress in another individual has been linked to elevated cortisol levels, a relation that is more robust in those with high trait empathy, whereas compassion has been linked to lower levels of cortisol reactivity. Preliminary studies of compassion training have found associations between the amount of time spent engaging in compassion training and inflammatory biomarkers, with more compassion training leading to decreased levels of both C-reactive protein and interleukin 6. These findings suggest that the mind can be trained to orient itself toward the well-being of others and that this shift from self- to other-orientation impacts both the brain and the peripheral biology of the body and, in particular, the way the body responds to environmental stressors. Further research is required to elucidate the precise mechanisms through which these states affect the body, and also to investigate how changes in peripheral biology reciprocally impact psychological processes and the relationship between these processes and well-being.

Brain imaging can predict six-year outcomes in children’s numerical abilities.

Interesting work from Evans et al.:

Significance Statement

Children show substantial individual differences in math abilities and ease of math learning. Early numerical abilities provide the foundation for future academic and professional success in an increasingly technological society. Understanding the early identification of poor math skills has therefore taken on great significance. This work provides important new insights into brain structure and connectivity measures that can predict longitudinal growth of children's math skills over a 6 year period, and may eventually aid in the early identification of children who might benefit from targeted interventions.

Abstract

Early numerical proficiency lays the foundation for acquiring quantitative skills essential in today's technological society. Identification of cognitive and brain markers associated with long-term growth of children's basic numerical computation abilities is therefore of utmost importance. Previous attempts to relate brain structure and function to numerical competency have focused on behavioral measures from a single time point. Thus, little is known about the brain predictors of individual differences in growth trajectories of numerical abilities. Using a longitudinal design, with multimodal imaging and machine-learning algorithms, we investigated whether brain structure and intrinsic connectivity in early childhood are predictive of 6 year outcomes in numerical abilities spanning childhood and adolescence. Gray matter volume at age 8 in distributed brain regions, including the ventrotemporal occipital cortex (VTOC), the posterior parietal cortex, and the prefrontal cortex, predicted longitudinal gains in numerical, but not reading, abilities. Remarkably, intrinsic connectivity analysis revealed that the strength of functional coupling among these regions also predicted gains in numerical abilities, providing novel evidence for a network of brain regions that works in concert to promote numerical skill acquisition. VTOC connectivity with posterior parietal, anterior temporal, and dorsolateral prefrontal cortices emerged as the most extensive network predicting individual gains in numerical abilities. Crucially, behavioral measures of mathematics, IQ, working memory, and reading did not predict children's gains in numerical abilities. Our study identifies, for the first time, functional circuits in the human brain that scaffold the development of numerical skills, and highlights potential biomarkers for identifying children at risk for learning difficulties.

Bioethics - Doing more harm than good?

Steven Pinker recently ignited a small firestorm with his piece in the Boston Globe arguing that bioethical issues that slow down research have a massive human cost. "Even a one-year delay in implementing an effective treatment could spell death, suffering, or disability for millions of people." Below are some clips from his piece, and rebuttals to Pinker's points can be found in this Nature article:

Biomedical research, then, promises vast increases in life, health, and flourishing. Just imagine how much happier you would be if a prematurely deceased loved one were alive, or a debilitated one were vigorous — and multiply that good by several billion, in perpetuity. Given this potential bonanza, the primary moral goal for today’s bioethics can be summarized in a single sentence.

Get out of the way.

A truly ethical bioethics should not bog down research in red tape, moratoria, or threats of prosecution based on nebulous but sweeping principles such as “dignity,” “sacredness,” or “social justice.” Nor should it thwart research that has likely benefits now or in the near future by sowing panic about speculative harms in the distant future. These include perverse analogies with nuclear weapons and Nazi atrocities, science-fiction dystopias like “Brave New World’’ and “Gattaca,’’ and freak-show scenarios like armies of cloned Hitlers, people selling their eyeballs on eBay, or warehouses of zombies to supply people with spare organs. Of course, individuals must be protected from identifiable harm, but we already have ample safeguards for the safety and informed consent of patients and research subjects.

Biomedical research in particular is defiantly unpredictable. The silver-bullet cancer cures of yesterday’s newsmagazine covers, like interferon and angiogenesis inhibitors, disappointed the breathless expectations, as have elixirs such as antioxidants, Vioxx, and hormone replacement therapy. Nineteen years after Dolly the sheep was cloned, we are nowhere near seeing parents implanting genes for musical, athletic, or intellectual talent in their unborn children.

In the other direction, treatments that were decried in their time as paving the road to hell, including vaccination, transfusions, anesthesia, artificial insemination, organ transplants, and in-vitro fertilization, have become unexceptional boons to human well-being.

Biomedical advances will always be incremental and hard-won, and foreseeable harms can be dealt with as they arise. The human body is staggeringly complex, vulnerable to entropy, shaped by evolution for youthful vigor at the expense of longevity, and governed by intricate feedback loops which ensure that any intervention will be compensated for by other parts of the system. Biomedical research will always be closer to Sisyphus than a runaway train — and the last thing we need is a lobby of so-called ethicists helping to push the rock down the hill.

Oxytocin - more sophisticated views of its functions

Helen Shen offers a review of studies on oxytocin, the “hug hormone,” which influences maternal behavior and social attachment in various species. She notes research showing that oxytocin acts on inhibitory interneurons in a way that quiets background chatter within neuronal circuits, and thus may help social interaction and recognition is by enhancing the brain's response to socially relevant sights, sounds or other stimuli. MindBlog has done posts on experiments showing that oxytocin, delivered through an intranasal spray, can promote various aspects of social behavior in healthy adults. People who inhale oxytocin before playing an investment game are more willing to entrust their money to a stranger than are placebo-treated players. A dose of the hormone increases the amount of time people spend gazing at the eye region of faces, and improves their ability to infer the emotional state of others from subtle expressions. Shen’s review also summarizes efforts to test oxytocin’s usefulness in treating psychiatric disorders such as autism.

Birth of the moralizing gods.

Lizzie Wade offers two interesting summaries of work on the evolution of religion that suggest that as societies grew bigger, so did their gods. She describes the efforts of Anders Petersen, who is asking religious studies scholars to contribute his "Database of Religious History" project by answering a series of questions about the ancient religions in which each of them specialize. This kind of survey can help in testing a “big gods” hypothesis: "Did moralizing gods, community-wide rituals, and supernatural punishment emerge before or after societies became politically complex? Has any large-scale society succeeded without prosocial religion? And what does “moralizing” really mean in different cultures and at different times?" Wade's second article describes work of Ara Norenzayan and others suggesting that judgemental deities were the key to obtaining the cooperation needed to build and sustain large and complex ancient societies..."once big gods and big societies existed, the moralizing gods helped religions as dissimilar as Islam and Mormonism spread by making groups of the faithful more cooperative, and therefore more successful."

The benefits of reading to children.

Two items...First, from Montag et al.:

Young children learn language from the speech they hear. Previous work suggests that greater statistical diversity of words and of linguistic contexts is associated with better language outcomes. One potential source of lexical diversity is the text of picture books that caregivers read aloud to children. Many parents begin reading to their children shortly after birth, so this is potentially an important source of linguistic input for many children. We constructed a corpus of 100 children’s picture books and compared word type and token counts in that sample and a matched sample of child-directed speech. Overall, the picture books contained more unique word types than the child-directed speech. Further, individual picture books generally contained more unique word types than length-matched, child-directed conversations. The text of picture books may be an important source of vocabulary for young children, and these findings suggest a mechanism that underlies the language benefits associated with reading to children.

And, Hutton et al. note that children with greater home reading exposure exhibit higher activation of left-sided brain regions involved with semantic processing (extraction of meaning).

Self-policing by psychologists - many prominent experiments fail replication tests

Benedict Carey offers context, summary, and reactions to the recent Science article reporting work of a consortium of 270 scientists on five continents led by psychologist Brian Nosek at the University of Virginia. (Other commentaries on this work are offered by Bohannon and by The Guardian.) The bottom line is that only 36 percent of the findings from almost 100 studies in the top three psychology journals held up when the original experiments were rigorously redone. This work was an 'inside job,' with psychologists doing the replication attempts communicating with cooperative original researchers. Carey describes a culture change that is taking hold in the psychological research community, towards greater transparency, data sharing, and preregistration of studies with journals that spells out hypotheses and how they are going to be tested. "Doing this upfront is a powerful check against moving the goal posts on a study — that is, analyzing the data and working backward, reverse-engineering the “hypothesis” to fit those findings."

(addendum 9/1/2015:  another useful commentary, "Psychology is Not in Crisis")

A beta-blocker facilitates fear extinction.

Fitzgerald et al. show, using a rat model, that propranolol, a β-noradrenergic receptor blocker, can facilitate extinction of posttraumatic stress. Significance

Posttraumatic stress disorder is characterized by a resistance to extinction learning and dysregulated signaling of the neurotransmitter norepinephrine. Previous research suggested the prelimbic and infralimbic subdivisions of the medial prefrontal cortex (mPFC) regulate fear expression and suppression, respectively. However, noradrenergic signaling in response to psychological stress may disrupt mPFC function, contributing to extinction deficits. Here we show, for the first time to our knowledge, that footshock stress dysregulates mPFC spike firing; this can be stabilized by propranolol, a β-noradrenergic receptor blocking drug, which in turn facilitates extinction when it normally fails. These findings suggest that propranolol may be a particularly effective adjunct to behavioral therapy soon after trauma, when stress is high, at least in part by normalizing prefrontal cortical function.

Abstract

Stress-induced impairments in extinction learning are believed to sustain posttraumatic stress disorder (PTSD). Noradrenergic signaling may contribute to extinction impairments by modulating medial prefrontal cortex (mPFC) circuits involved in fear regulation. Here we demonstrate that aversive fear conditioning rapidly and persistently alters spontaneous single-unit activity in the prelimbic and infralimbic subdivisions of the mPFC in behaving rats. These conditioning-induced changes in mPFC firing were mitigated by systemic administration of propranolol (10 mg/kg, i.p.), a β-noradrenergic receptor antagonist. Moreover, propranolol administration dampened the stress-induced impairment in extinction observed when extinction training is delivered shortly after fear conditioning. These findings suggest that β-adrenoceptors mediate stress-induced changes in mPFC spike firing that contribute to extinction impairments. Propranolol may be a helpful adjunct to behavioral therapy for PTSD, particularly in patients who have recently experienced trauma.

The collaborative roots of corruption.

Here is a neat piece of work, by Weisel and Shalvi:

Significance

Recent financial scandals highlight the devastating consequences of corruption. While much is known about individual immoral behavior, little is known about the collaborative roots of corruption. In a novel experimental paradigm, people could adhere to one of two competing moral norms: collaborate vs. be honest. Whereas collaborative settings may boost honesty due to increased observability, accountability, and reluctance to force others to become accomplices, we show that collaboration, particularly on equal terms, is inductive to the emergence of corruption. When partners' profits are not aligned, or when individuals complete a comparable task alone, corruption levels drop. These findings reveal a dark side of collaboration, suggesting that human cooperative tendencies, and not merely greed, take part in shaping corruption.

Abstract

Cooperation is essential for completing tasks that individuals cannot accomplish alone. Whereas the benefits of cooperation are clear, little is known about its possible negative aspects. Introducing a novel sequential dyadic die-rolling paradigm, we show that collaborative settings provide fertile ground for the emergence of corruption. In the main experimental treatment the outcomes of the two players are perfectly aligned. Player A privately rolls a die, reports the result to player B, who then privately rolls and reports the result as well. Both players are paid the value of the reports if, and only if, they are identical (e.g., if both report 6, each earns €6). Because rolls are truly private, players can inflate their profit by misreporting the actual outcomes. Indeed, the proportion of reported doubles was 489% higher than the expected proportion assuming honesty, 48% higher than when individuals rolled and reported alone, and 96% higher than when lies only benefited the other player. Breaking the alignment in payoffs between player A and player B reduced the extent of brazen lying. Despite player B's central role in determining whether a double was reported, modifying the incentive structure of either player A or player B had nearly identical effects on the frequency of reported doubles. Our results highlight the role of collaboration—particularly on equal terms—in shaping corruption. These findings fit a functional perspective on morality. When facing opposing moral sentiments—to be honest vs. to join forces in collaboration—people often opt for engaging in corrupt collaboration.

What emotions are and aren’t.

Barrett uses a very useful analogy to describe the misguided search for "where in the brain" particular emotions occur:

...if you listen to a recorded symphony through stereo speakers that are placed exactly right, the orchestra will sound like it’s inside your head. Obviously that isn’t the case...You might find yourself asking well-meaning but preposterous scientific questions like “Where in the brain is the woodwinds section located?” ..A more reasonable approach is not to ask...How does the brain construct this experience of hearing the orchestra in your head?

Most people, including many scientists, believe that emotions are distinct, locatable entities inside us — but they’re not. Searching for emotions in this form is as misguided as looking for cerebral clarinets and oboes.

The Interdisciplinary Affective Science Laboratory (which I direct) collectively analyzed brain-imaging studies published from 1990 to 2011 that examined fear, sadness, anger, disgust and happiness. We divided the human brain virtually into tiny cubes, like 3-D pixels, and computed the probability that studies of each emotion found an increase in activation in each cube...Overall, we found that no brain region was dedicated to any single emotion. We also found that every alleged “emotion” region of the brain increased its activity during nonemotional thoughts and perceptions as well.

Brain regions like the amygdala are certainly important to emotion, but they are neither necessary nor sufficient for it. In general, the workings of the brain are not one-to-one, whereby a given region has a distinct psychological purpose. Instead, a single brain area like the amygdala participates in many different mental events, and many different brain areas are capable of producing the same outcome. Emotions like fear and anger, my lab has found, are constructed by multipurpose brain networks that work together.

If emotions are not distinct neural entities, perhaps they have a distinct bodily pattern — heart rate, respiration, perspiration, temperature and so on? Again, the answer is no. My lab analyzed over 200 published studies, covering nearly 22,000 test subjects, and found no consistent and specific fingerprints in the body for any emotion. Instead, the body acts in diverse ways that are tied to the situation.

...emotion words like “anger,” “happiness” and “fear” each name a population of diverse biological states that vary depending on the context...Instead of asking where emotions are or what bodily patterns define them, we would do better to abandon such essentialism and ask the more revealing question, “How does the brain construct these incredible experiences?”