Friday, September 30, 2016

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

From Maher et al.:

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.
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.

Thursday, September 29, 2016

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.

Wednesday, September 28, 2016

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.
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.
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.

Tuesday, September 27, 2016

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.”

Monday, September 26, 2016

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.

Friday, September 23, 2016

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.

Thursday, September 22, 2016

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.

Wednesday, September 21, 2016

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.

Tuesday, September 20, 2016

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.

Monday, September 19, 2016

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.

Friday, September 16, 2016

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.)

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.
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.

Thursday, September 15, 2016

Self-regulation via neural simulation

A fascinating study from Gilead et al.:

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.
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.

Wednesday, September 14, 2016

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.

Tuesday, September 13, 2016

The ecstasy of speed - or leisure?

Because I so frequently feel overwhelmed by input streams of chunks of information, I wonder how readers of this blog manage to find time to attend to its contents. (I am gratified that so many seem to do so.) Thoughts like this made me pause over Maria Popova's recent essay on our anxiety about time. I want to pass on a few clips, and recommend that you read all of it. She quotes extensively from James Gleick's book published in 2000: "Faster: The Acceleration of Just About Everything.", and begins by noting a 1918 Bertrand Russell quote, “both in thought and in feeling, even though time be real, to realise the unimportance of time is the gate of wisdom.”
Half a century after German philosopher Josef Pieper argued that leisure is the basis of culture and the root of human dignity, Gleick writes:
We are in a rush. We are making haste. A compression of time characterizes the life of the century....We have a word for free time: leisure. Leisure is time off the books, off the job, off the clock. If we save time, we commonly believe we are saving it for our leisure. We know that leisure is really a state of mind, but no dictionary can define it without reference to passing time. It is unrestricted time, unemployed time, unoccupied time. Or is it? Unoccupied time is vanishing. The leisure industries (an oxymoron maybe, but no contradiction) fill time, as groundwater fills a sinkhole. The very variety of experience attacks our leisure as it attempts to satiate us. We work for our amusement...Sociologists in several countries have found that increasing wealth and increasing education bring a sense of tension about time. We believe that we possess too little of it: that is a myth we now live by.
To fully appreciate Gleick’s insightful prescience, it behooves us to remember that he is writing long before the social web as we know it, before the conspicuous consumption of “content” became the currency of the BuzzMalnourishment industrial complex, before the timelines of Twitter and Facebook came to dominate our record and experience of time. (Prescience, of course, is a form of time travel — perhaps our only nonfictional way to voyage into the future.) Gleick writes:
We live in the buzz. We wish to live intensely, and we wonder about the consequences — whether, perhaps, we face the biological dilemma of the waterflea, whose heart beats faster as the temperature rises. This creature lives almost four months at 46 degrees Fahrenheit but less than one month at 82 degrees...Yet we have made our choices and are still making them. We humans have chosen speed and we thrive on it — more than we generally admit. Our ability to work fast and play fast gives us power. It thrills us… No wonder we call sudden exhilaration a rush.
Gleick considers what our units of time reveal about our units of thought:
We have reached the epoch of the nanosecond. This is the heyday of speed. “Speed is the form of ecstasy the technical revolution has bestowed on man,” laments the Czech novelist Milan Kundera, suggesting by ecstasy a state of simultaneous freedom and imprisonment… That is our condition, a culmination of millennia of evolution in human societies, technologies, and habits of mind.
The more I experience and read about the winding up and acceleration of our lives (think of the rate and omnipresence of the current presidential campaign!),  the more I realize the importance of rediscovering the sanity of leisure and quiet spaces.

Monday, September 12, 2016

Mind and Body - A neural substrate of psychosomatic illness

We all have our "hot buttons" - events or issues that can trigger an acute stress response as our adrenal medulla releases adrenaline, causing heart rate increases, sweating, pupil dilation, etc. Dum et al. use a clever tracer technique to show neural connections between the adrenal medulla and higher cortical centers that might exert a 'top-down' cognitive control of this arousal:

How does the “mind” (brain) influence the “body” (internal organs)? We identified key areas in the primate cerebral cortex that are linked through multisynaptic connections to the adrenal medulla. The most substantial influence originates from a broad network of motor areas that are involved in all aspects of skeletomotor control from response selection to motor preparation and movement execution. A smaller influence originates from a network in medial prefrontal cortex that is involved in the regulation of cognition and emotion. Thus, cortical areas involved in the control of movement, cognition, and affect are potential sources of central commands to influence sympathetic arousal. These results provide an anatomical basis for psychosomatic illness where mental states can alter organ function.
Modern medicine has generally viewed the concept of “psychosomatic” disease with suspicion. This view arose partly because no neural networks were known for the mind, conceptually associated with the cerebral cortex, to influence autonomic and endocrine systems that control internal organs. Here, we used transneuronal transport of rabies virus to identify the areas of the primate cerebral cortex that communicate through multisynaptic connections with a major sympathetic effector, the adrenal medulla. We demonstrate that two broad networks in the cerebral cortex have access to the adrenal medulla. The larger network includes all of the cortical motor areas in the frontal lobe and portions of somatosensory cortex. A major component of this network originates from the supplementary motor area and the cingulate motor areas on the medial wall of the hemisphere. These cortical areas are involved in all aspects of skeletomotor control from response selection to motor preparation and movement execution. The second, smaller network originates in regions of medial prefrontal cortex, including a major contribution from pregenual and subgenual regions of anterior cingulate cortex. These cortical areas are involved in higher-order aspects of cognition and affect. These results indicate that specific multisynaptic circuits exist to link movement, cognition, and affect to the function of the adrenal medulla. This circuitry may mediate the effects of internal states like chronic stress and depression on organ function and, thus, provide a concrete neural substrate for some psychosomatic illness.

Friday, September 09, 2016

Want to predict a group’s social standing? Get a hormonal profile.

Usually the analysis of a group's social standing is attempted by determining demographic or psychological characteristics of group members. Akinola et al. suggest that the collective hormonal profile of the group can be equally predictive, and provides a neurobiological perspective on the factors that determine who rises to the top across, not just within, social hierarchies:

Past research has focused primarily on demographic and psychological characteristics of group members without taking into consideration the biological make-up of groups. Here we introduce a different construct—a group’s collective hormonal profile—and find that a group’s biological profile predicts its standing across groups and that the particular profile supports a dual-hormone hypothesis. Groups with a collective hormonal profile characterized by high testosterone and low cortisol exhibit the highest performance. The current work provides a neurobiological perspective on factors determining group behavior and performance that are ripe for further exploration.
Prior research has shown that an individual’s hormonal profile can influence the individual’s social standing within a group. We introduce a different construct—a collective hormonal profile—which describes a group’s hormonal make-up. We test whether a group’s collective hormonal profile is related to its performance. Analysis of 370 individuals randomly assigned to work in 74 groups of three to six individuals revealed that group-level concentrations of testosterone and cortisol interact to predict a group’s standing across groups. Groups with a collective hormonal profile characterized by high testosterone and low cortisol exhibited the highest performance. These collective hormonal level results remained reliable when controlling for personality traits and group-level variability in hormones. These findings support the hypothesis that groups with a biological propensity toward status pursuit (high testosterone) coupled with reduced stress-axis activity (low cortisol) engage in profit-maximizing decision-making. The current work extends the dual-hormone hypothesis to the collective level and provides a neurobiological perspective on the factors that determine who rises to the top across, not just within, social hierarchies.

Thursday, September 08, 2016

Reason is not required for a life of meaning.

Robert Burton, former neurology chief at UCSF and a neuroscience author, has contributed an excellent short essay to the NYTimes philosophy series The Stone. A few clips:
Few would disagree with two age-old truisms: We should strive to shape our lives with reason, and a central prerequisite for the good life is a personal sense of meaning...Any philosophical approach to values and purpose must acknowledge this fundamental neurological reality: a visceral sense of meaning in one’s life is an involuntary mental state that, like joy or disgust, is independent from and resistant to the best of arguments...Anyone who has experienced a bout of spontaneous depression knows the despair of feeling that nothing in life is worth pursuing and that no argument, no matter how inspired, can fill the void. Similarly, we are all familiar with the countless narratives of religious figures “losing their way” despite retaining their formal beliefs.
As neuroscience attempts to pound away at the idea of pure rationality and underscore the primacy of subliminal mental activity, I am increasingly drawn to the metaphor of idiosyncratic mental taste buds. From genetic factors (a single gene determines whether we find brussels sprouts bitter or sweet), to the cultural — considering fried grasshoppers and grilled monkey brains as delicacies — taste isn’t a matter of the best set of arguments...If thoughts, like foods, come in a dazzling variety of flavors, and personal taste trumps reason, philosophy — which relies most heavily on reason, and aims to foster the acquisition of objective knowledge — is in a bind.
Though we don’t know how thoughts are produced by the brain, it is hard to imagine having a thought unaccompanied by some associated mental state. We experience a thought as pleasing, revolting, correct, incorrect, obvious, stupid, brilliant, etc. Though integral to our thoughts, these qualifiers arise out of different brain mechanisms from those that produce the raw thought. As examples, feelings of disgust, empathy and knowing arise from different areas of brain and can be provoked de novo in volunteer subjects via electrical stimulation even when the subjects are unaware of having any concomitant thought at all. This chicken-and-egg relationship between feelings and thought can readily be seen in how we make moral judgments...The psychologist Jonathan Haidt and others have shown that our moral stances strongly correlate with the degree of activation of those brain areas that generate a sense of disgust and revulsion. According to Haidt, reason provides an after-the-fact explanation for moral decisions that are preceded by inherently reflexive positive or negative feelings. Think about your stance on pedophilia or denying a kidney transplant to a serial killer.
After noting work of Libet and others showing that our sense of agency is an illusion - initiating an action occurs well after our brains have already started that action, especially in tennis players and baseball batters - Burton suggests that:
It is unlikely that there is any fundamental difference in how the brain initiates thought and action. We learn the process of thinking incrementally, acquiring knowledge of language, logic, the external world and cultural norms and expectations just as we learn physical actions like talking, walking or playing the piano. If we conceptualize thought as a mental motor skill subject to the same temporal reorganization as high-speed sports, it’s hard to avoid the conclusion that the experience of free will (agency) and conscious rational deliberation are both biologically generated illusions.
What then are we to do with the concept of rationality? It would be a shame to get rid of a term useful in characterizing the clarity of a line of reasoning. Everyone understands that “being rational” implies trying to strip away biases and innate subjectivity in order to make the best possible decision. But what if the word rational leads us to scientifically unsound conclusions?
Going forward, the greatest challenge for philosophy will be to remain relevant while conceding that, like the rest of the animal kingdom, we are decision-making organisms rather than rational agents, and that our most logical conclusions about moral and ethical values can’t be scientifically verified nor guaranteed to pass the test of time. (The history of science should serve as a cautionary tale for anyone tempted to believe in the persistent truth of untestable ideas).
Even so, I would hate to discard such truisms such as “know thyself” or “the unexamined life isn’t worth living.” Reason allows us new ways of seeing, just as close listening to a piece of music can reveal previously unheard melodies and rhythms or observing an ant hill can give us an unexpected appreciation of nature’s harmonies. These various forms of inquiry aren’t dependent upon logic and verification; they are modes of perception.

Wednesday, September 07, 2016

Brain network characteristics of highly intelligent people.

Schultz and Cole show that higher intelligence is associated with less task-related brain network reconfiguration:

The brain's network configuration varies based on current task demands. For example, functional brain connections are organized in one way when one is resting quietly but in another way if one is asked to make a decision. We found that the efficiency of these updates in brain network organization is positively related to general intelligence, the ability to perform a wide variety of cognitively challenging tasks well. Specifically, we found that brain network configuration at rest was already closer to a wide variety of task configurations in intelligent individuals. This suggests that the ability to modify network connectivity efficiently when task demands change is a hallmark of high intelligence.
The human brain is able to exceed modern computers on multiple computational demands (e.g., language, planning) using a small fraction of the energy. The mystery of how the brain can be so efficient is compounded by recent evidence that all brain regions are constantly active as they interact in so-called resting-state networks (RSNs). To investigate the brain's ability to process complex cognitive demands efficiently, we compared functional connectivity (FC) during rest and multiple highly distinct tasks. We found previously that RSNs are present during a wide variety of tasks and that tasks only minimally modify FC patterns throughout the brain. Here, we tested the hypothesis that, although subtle, these task-evoked FC updates from rest nonetheless contribute strongly to behavioral performance. One might expect that larger changes in FC reflect optimization of networks for the task at hand, improving behavioral performance. Alternatively, smaller changes in FC could reflect optimization for efficient (i.e., small) network updates, reducing processing demands to improve behavioral performance. We found across three task domains that high-performing individuals exhibited more efficient brain connectivity updates in the form of smaller changes in functional network architecture between rest and task. These smaller changes suggest that individuals with an optimized intrinsic network configuration for domain-general task performance experience more efficient network updates generally. Confirming this, network update efficiency correlated with general intelligence. The brain's reconfiguration efficiency therefore appears to be a key feature contributing to both its network dynamics and general cognitive ability.

Tuesday, September 06, 2016

Feeling Good? Do something unpleasant.

A curious piece from Taquet et al.:
Most theories of motivation have highlighted that human behavior is guided by the hedonic principle, according to which our choices of daily activities aim to minimize negative affect and maximize positive affect. However, it is not clear how to reconcile this idea with the fact that people routinely engage in unpleasant yet necessary activities. To address this issue, we monitored in real time the activities and moods of over 28,000 people across an average of 27 d using a multiplatform smartphone application. We found that people’s choices of activities followed a hedonic flexibility principle. Specifically, people were more likely to engage in mood-increasing activities (e.g., play sports) when they felt bad, and to engage in useful but mood-decreasing activities (e.g., housework) when they felt good. These findings clarify how hedonic considerations shape human behavior. They may explain how humans overcome the allure of short-term gains in happiness to maximize long-term welfare.

Monday, September 05, 2016

Do your friends really like you?

I found this article by Murphy pointing to work by Almaatouq et al. to align with my recent experience of having two long term friends (or so I thought), simply stop responding to emails about getting together. And, from the other direction, being described as "our good friend" by a couple I didn't particularly like. It turns out that studies show that only about half of perceived friendships are mutual. The Alamaatouq et al. study:
...analyzed friendship ties among 84 subjects (ages 23 to 38) in a business management class by asking them to rank one another on a five-point continuum of closeness from “I don’t know this person” to “One of my best friends.” The feelings were mutual 53 percent of the time while the expectation of reciprocity was pegged at 94 percent. This is consistent with data from several other friendship studies conducted over the past decade, encompassing more than 92,000 subjects, in which the reciprocity rates ranged from 34 percent to 53 percent.
Clips from the last portion of Murphy's article:
Because time is limited, so, too, is the number of friends you can have, according to the work of the British evolutionary psychologist Robin I.M. Dunbar. He describes layers of friendship, where the topmost layer consists of only one or two people, say a spouse and best friend with whom you are most intimate and interact daily. The next layer can accommodate at most four people for whom you have great affinity, affection and concern and who require weekly attention to maintain. Out from there, the tiers contain more casual friends with whom you invest less time and tend to have a less profound and more tenuous connection. Without consistent contact, they easily fall into the realm of acquaintance.
...playing it safe by engaging in shallow, unfulfilling or nonreciprocal relationships has physical repercussions. Not only do the resulting feelings of loneliness and isolation increase the risk of death as much as smoking, alcoholism and obesity; you may also lose tone, or function, in the so-called smart vagus nerve, which brain researchers think allows us to be in intimate, supportive and reciprocal relationships in the first place...In the presence of a true friend...the smart or modulating aspect of the vagus nerve is what makes us feel at ease rather than on guard as when we are with a stranger or someone judgmental. It’s what enables us to feel O.K. about exposing the soft underbelly of our psyche and helps us stay engaged and present in times of conflict. Lacking authentic friendships, the smart vagus nerve is not exercised. It loses tone and one’s anxiety remains high, making abiding, deep connections difficult.

Friday, September 02, 2016

Growing Older, Getting Happier

A brief piece from Nicholas Bakalar in the NYTimes summaring the recent paper by Thomas et al. (senior author Dilip Jeste):
Older people tend to be happier than younger people, and their happiness increases with age...Researchers contacted 1,546 people ages 21 to 99 via random telephone calls and found that older age was, not surprisingly, tied to declines in physical and cognitive function. But it was also associated with higher levels of overall satisfaction, happiness and well-being, and lower levels of anxiety, depression and stress. The older the person, the study found, the better his or her mental health tended to be.
The researchers used well-validated scales to assess mental health, although the study relied on self-reports and was a snapshot in time that did not follow an individual through a lifetime. Other studies have found similar results linking advancing age and higher levels of happiness.
The reasons for the effect remain unclear, but the senior author, Dr. Dilip V. Jeste, a professor of psychiatry at the University of California, San Diego, had some suggestions...“Brain studies show that the amygdala in older people responds less to stressful or negative images than in a younger person,” he said. “We become wise. Peer pressure loses its sting. Better decision-making, more control of emotions, doing things that are not just for yourself, knowing oneself better, being more studious and yet more decisive...“This is good news for young people, too,” he added. “You have something to look forward to.”
Here are the methods and results sections from the abstract:
Methods: Cross-sectional data were obtained from 1,546 individuals aged 21–100 years, selected using random digit dialing for the Successful AGing Evaluation (SAGE) study, a structured multicohort investigation that included telephone interviews and in-home surveys of community-based adults without dementia. Data were collected from 1/26/2010 to 10/07/2011 targeting participants aged 50–100 years and from 6/25/2012 to 7/15/2013 targeting participants aged 21–100 years with an emphasis on adding younger individuals. Data included self-report measures of physical health, measures of both positive and negative attributes of mental health, and a phone interview–based measure of cognition.
Results: Comparison of age cohorts using polynomial regression suggested a possible accelerated deterioration in physical and cognitive functioning, averaging 1.5 to 2 standard deviations over the adult lifespan. In contrast, there appeared to be a linear improvement of about 1 standard deviation in various attributes of mental health over the same life period.

Thursday, September 01, 2016