Impulse control with weak currents applied to the head - a new therapy?

Spieser et al. apply a very small current (1 milliamp) using the electrodes shown in the figure to slightly hyperpolarize, or make less excitable, the supplementary motor cortex, and find that this inhibits impulsive responses in a reaction time task.

To err is human. However, an inappropriate urge does not always result in error. Impulsive errors thus entail both a motor system capture by an urge to act and a failed inhibition of that impulse. Here we show that neuromodulatory electrical stimulation of the supplementary motor complex in healthy humans leaves action urges unchanged but prevents them from turning into overt errors. Subjects performed a choice reaction-time task known to trigger impulsive responses, leading to fast errors that can be revealed by analyzing accuracy as a function of poststimulus time. Yet, such fast errors are only the tip of the iceberg: electromyography (EMG) revealed fast subthreshold muscle activation in the incorrect response hand in an even larger proportion of overtly correct trials, revealing covert response impulses not discernible in overt behavior. Analyzing both overt and covert response tendencies enables to gauge the ability to prevent these incorrect impulses from turning into overt action errors. Hyperpolarizing the supplementary motor complex using transcranial direct current stimulation (tDCS) preserves action impulses but prevents their behavioral expression. This new combination of detailed behavioral, EMG, and tDCS techniques clarifies the neurophysiology of impulse control, and may point to avenues for improving impulse control deficits in various neurologic and psychiatric disorders.

Losing the music - Aging affects the perception of musical harmony

An open access article from Bones and Plack:

When two musical notes with simple frequency ratios are played simultaneously, the resulting musical chord is pleasing and evokes a sense of resolution or “consonance”. Complex frequency ratios, on the other hand, evoke feelings of tension or “dissonance”. Consonance and dissonance form the basis of harmony, a central component of Western music. In earlier work, we provided evidence that consonance perception is based on neural temporal coding in the brainstem (Bones et al., 2014). Here, we show that for listeners with clinically normal hearing, aging is associated with a decline in both the perceptual distinction and the distinctiveness of the neural representations of different categories of two-note chords. Compared with younger listeners, older listeners rated consonant chords as less pleasant and dissonant chords as more pleasant. Older listeners also had less distinct neural representations of consonant and dissonant chords as measured using a Neural Consonance Index derived from the electrophysiological “frequency-following response.” The results withstood a control for the effect of age on general affect, suggesting that different mechanisms are responsible for the perceived pleasantness of musical chords and affective voices and that, for listeners with clinically normal hearing, age-related differences in consonance perception are likely to be related to differences in neural temporal coding.

By the way, the same issue of J. Neuroscience has another interesting article by Vaden et al. on noting cingulo-opercular cortical activity that predicts how well older adults recognize speech in noise.

Thomas Metzinger on (the absence of) our conscious agency.

The edge.org question for 2014 was “What scientific idea is ready for retirement?” I want to pass on a few clips from Metzinger’s lucid brief contribution, and strongly suggest that you read it.

Thinking is not something you do. Most of the time it is something that happens to you. Cutting-edge research on the phenomenon of Mind Wandering now clearly shows how almost all of us, for more than two thirds of their conscious lifetime, are not in control of their conscious thought processes…The sudden loss of inner autonomy—which all of us experience many hundred times every day—seems to be based on a cyclically recurring process in the brain. The ebb and flow of autonomy and meta-awareness might well be a kind of attentional see-sawing between our inner and outer worlds, caused by a constant competition between the brain networks underlying spontaneous subpersonal thinking and goal-oriented cognition.

Interestingly, the neural correlate of non-autonomous conscious thought overlaps to a considerable degree with ongoing activity in what neuroscientists call the "default mode network". I think that one global function of Mind Wandering may be "autobiographical self-model maintenance". Mind Wandering creates an adaptive form of self-deception, namely, an illusion of personal identity across time. It helps to maintain a fictional "self" that then lays the foundation for important achievements like reward prediction or delay discounting. As a philosopher, my conceptual point is that only if an organism simulates itself as being one and the same across time will it be able to represent reward events or the achievement of goals as a fulfillment of its own goals, as happening to the same entity. I like to call this the "Principle of Virtual Identity Formation": Many higher forms of intelligence and adaptive behavior, including risk management, moral cognition and cooperative social behavior, functionally presuppose a self-model that portrays the organism as a single entity that endures over time. Because we are really only cognitive systems, complex processes without any precise identity criteria, the formation of an (illusory) identity across time can only be achieved on a virtual level, for example through the creation of an automatic narrative. This could be the more fundamental and overarching computational goal of mind wandering, and one it may share with dreaming. If I am right, the default mode of the autobiographical self-modeling constructs a domain-general functional platform enabling long-term motivation and future planning.

Mental autonomy (and how it can be improved) will be one of the hottest topics for the future. There is even a deep link between mental and political autonomy—you cannot sustain one without the other. Because there are not only bodily actions, but also mental actions, autonomy has to do with freedom—and in one of the deepest and most fundamental senses of the word. But the ability to act autonomously implies not only reasons, arguments and rationality. Much more fundamentally it refers to the capacity to wilfully inhibit, suspend, or terminate our own actions—bodily, socially, or mentally. The breakdown of this ability is what we call Mind Wandering.

Hunger promotes acquisition of nonfood objects

Here is a fascinating nugget of information from Xu et al.:

Hunger motivates people to consume food, for which finding and acquiring food is a prerequisite. We test whether the acquisition component spills over to nonfood objects: Are hungry people more likely to acquire objects that cannot satisfy their hunger? Five laboratory and field studies show that hunger increases the accessibility of acquisition-related concepts and the intention to acquire not only food but also nonfood objects. Moreover, people act on this intention and acquire more nonfood objects (e.g., binder clips) when they are hungry, both when these items are freely available and when they must be paid for. However, hunger does not influence how much they like nonfood objects. We conclude that a basic biologically based motivation can affect substantively unrelated behaviors that cannot satisfy the motivation. This presumably occurs because hunger renders acquisition-related concepts and behaviors more accessible, which influences decisions in situations to which they can be applied.

What can music ensembles tell us about social cognition and interaction?

D'Ausilio et al. note that most studies of how cognition and brain organization is shaped by social factors have used subjects in defined experimental settings, rather than natural ones. The problem is that experimental rigor is inversely related to ecological naturalness. They suggest that musical ensemble performance offers a promising solution for balancing the trade-off between experimental control and ecological naturalness. Here is their list of features that make music a promising avenue for social cognition research.

Ecological validity: ensemble musicians participate in a socially-relevant interaction, obviating the need to introduce an artificial task, manipulation, or training to induce a social context.

Motivational factors: motivation is an inherent part of music and hence it is not necessary to employ extrinsic techniques (monetary compensation, competition, or response-contingent reward) to trigger the emergence of interaction.

Generalizability: musicality is a widespread human capacity, enabling almost everyone to sing together with others and to produce rhythms through body movements (e.g., simple drumming or dance).

Multi-level interactivity: information transfer is both continuous (body movements) and discrete (musical sounds). Furthermore, musicians’ movements that function to produce sound on an instrument can be dissociated from those that are not necessary for sound production (e.g., ancillary movements that serve expressive functions) [15]. These properties allow the investigation of the multi-level communicative functions (hierarchical musical structure and expressive intentions) of musical social interaction.

Temporal dependencies: information transfer is not only based on the content of an individual's instantaneous response but also is affected by rhythmic timing, tempo, and the degree of interpersonal synchrony.

Formal description of interaction: the musical score is a script-like description of the interaction that the experimenter can manipulate to control the emergence of social structures and different roles (e.g., leader vs follower) played by each musician.

The authors briefly review research that that traverses a continuum of ecological interaction. These classes include an individual interacting with a recording, a computer-controlled virtual partner that responds to the individual, another individual in a duo, multiple individuals in mixed ensembles (extending to large orchestras), and others in the presence of a live audience.

The happiness gap between conservatives and liberals debunked

Given the number of MindBlog posts that have passed on research supporting the standard orthodoxy that conservatives are happier than liberals, I immediately pass on this abstract from Wojcik et al. reporting experiments that prove just the opposite (See also the NYTimes summary of this work.)

Research suggesting that political conservatives are happier than political liberals has relied exclusively on self-report measures of subjective well-being. We show that this finding is fully mediated by conservatives’ self-enhancing style of self-report (study 1; N = 1433) and then describe three studies drawing from “big data” sources to assess liberal-conservative differences in happiness-related behavior (studies 2 to 4; N = 4936). Relative to conservatives, liberals more frequently used positive emotional language in their speech and smiled more intensely and genuinely in photographs. Our results were consistent across large samples of online survey takers, U.S. politicians, Twitter users, and LinkedIn users. Our findings illustrate the nuanced relationship between political ideology, self-enhancement, and happiness and illuminate the contradictory ways that happiness differences can manifest across behavior and self-reports.

Emotional foundations of cognitive control.

Cognitive control (self control, self regulation) allows us to restrain from temptations of the present to focus on more long term goals. Emotion is usually cast as its enemy. Inzlicht et al. suggest, however, that cognitive control rises from and is dependent on emotional primitives, in particular the negative affect associated with conflicting stimuli.  Their highlights and abstract:

• Cognitive control can be understood as an emotional process. 

• Negative affect is an integral, instantiating aspect of cognitive control. 

• Cognitive conflict has an emotional cost, evoking a host of emotional primitives. 

• Emotion is not an inert byproduct of conflict, but helps in recruiting control.

Often seen as the paragon of higher cognition, here we suggest that cognitive control is dependent on emotion. Rather than asking whether control is influenced by emotion, we ask whether control itself can be understood as an emotional process. Reviewing converging evidence from cybernetics, animal research, cognitive neuroscience, and social and personality psychology, we suggest that cognitive control is initiated when goal conflicts evoke phasic changes to emotional primitives that both focus attention on the presence of goal conflicts and energize conflict resolution to support goal-directed behavior. Critically, we propose that emotion is not an inert byproduct of conflict but is instrumental in recruiting control. Appreciating the emotional foundations of control leads to testable predictions that can spur future research.

Observing brain correlates of self affirmation and its healthy consequences

From the introduction of Falk et. al. :

...according to the World Health Organization, “60% to 85% of people in the world—from both developed and developing countries—lead sedentary lifestyles”...self-relevant health messages can be perceived to be threatening to self-worth and are often met with resistance...Affirmation of core values (self-affirmation) preceding potentially threatening messages can reduce resistance and increase intervention effectiveness Therefore, one way to increase receptivity to messages discouraging sedentary behavior among sedentary individuals may be to affirm their core values in unrelated domains before exposure to the messages.

We focused on the brain’s ventromedial prefrontal cortex (VMPFC) during exposure to potentially threatening health messages emphasizing the need to be more active and less sedentary in a group of sedentary adults. VMPFC is the most common region implicated in self-related processing and is also a key region, along with the ventral striatum, implicated in positive valuation of stimuli.

Their abstract:

Health communications can be an effective way to increase positive health behaviors and decrease negative health behaviors; however, those at highest risk are often most defensive and least open to such messages. For example, increasing physical activity among sedentary individuals affects a wide range of important mental and physical health outcomes, but has proven a challenging task. Affirming core values (i.e., self-affirmation) before message exposure is a psychological technique that can increase the effectiveness of a wide range of interventions in health and other domains; however, the neural mechanisms of affirmation’s effects have not been studied. We used functional magnetic resonance imaging (fMRI) to examine neural processes associated with affirmation effects during exposure to potentially threatening health messages. We focused on an a priori defined region of interest (ROI) in ventromedial prefrontal cortex (VMPFC), a brain region selected for its association with self-related processing and positive valuation. Consistent with our hypotheses, those in the self-affirmation condition produced more activity in VMPFC during exposure to health messages and went on to increase their objectively measured activity levels more. These findings suggest that affirmation of core values may exert its effects by allowing at-risk individuals to see the self-relevance and value in otherwise-threatening messages.

(A) VMPFC ROI. (B) Participants who showed higher levels of VMPFC activity during exposure to health messages subsequently decreased their sedentary behavior more in the month following the scan, controlling for baseline sedentary behavior and demographics.

Spontaneous emergence of shared social conventions.

Centola and Baronchelli have recruited subjects from the world wide web to play a live game. They demonstate that myopic players interacting in sequential pairs in social networks can unintentionally create percolating cascades of coordinated behavior. Their findings demonstrate that social conventions can spontaneously evolve in large human populations without any institutional mechanisms to facilitate the process. The results highlight the causal role played by network connectivity in the dynamics of establishing shared norms. I pass on first the abstract and then sections on experimental design and methods.

How do shared conventions emerge in complex decentralized social systems? This question engages fields as diverse as linguistics, sociology, and cognitive science. Previous empirical attempts to solve this puzzle all presuppose that formal or informal institutions, such as incentives for global agreement, coordinated leadership, or aggregated information about the population, are needed to facilitate a solution. Evolutionary theories of social conventions, by contrast, hypothesize that such institutions are not necessary in order for social conventions to form. However, empirical tests of this hypothesis have been hindered by the difficulties of evaluating the real-time creation of new collective behaviors in large decentralized populations. Here, we present experimental results—replicated at several scales—that demonstrate the spontaneous creation of universally adopted social conventions and show how simple changes in a population’s network structure can direct the dynamics of norm formation, driving human populations with no ambition for large scale coordination to rapidly evolve shared social conventions.

Experimental Design

Each live game, or experimental “trial,” consisted of a set of participants, a specific social network structure, and a prespecified number of rounds to play. When participants arrived to play the game, they were randomly assigned to positions within a social network. In a given round of the game, two network “neighbors” were chosen at random to play with one another. Both players simultaneously assigned names to a pictured object (i.e., a human face), blindly attempting to coordinate in the real-time exchange of naming choices. If the players coordinated on a name, they were rewarded with a successful payment; if they failed, they were penalized (Materials and Methods). After a single round, the participants could see only the choices that they and their partner had made, and their cumulative pay was updated accordingly. They were then randomly assigned to play with a new neighbor in their social network, and a new round would begin. The object that participants were trying to name was the same for the entire duration of the game, and for all members of the game. Participants in the study did not have any information about the size of the population that was attempting to coordinate nor about the number of neighbors to whom they were connected.

Materials and Methods

Participants in the study were recruited at large from the World Wide Web. When participants arrived to play a game, they were randomly assigned to an experimental condition (i.e., a social network) and then randomly assigned to a position within that social network. In a given round of the game, two network neighbors were chosen at random to play with one another. Both players simultaneously assigned names to a pictured object (e.g., a human face), blindly attempting to coordinate in the real-time exchange of naming choices. If the players coordinated on a name, they were rewarded with a successful payment ($0.50); if they failed, they were penalized (–$0.25). (Participants could not go into debt, so failures did not incur a penalty if a participant had a balance of $0.) After a single round, the participants could see only the choices that they and their partner had made, and their cumulative pay was updated accordingly. They were then randomly assigned to play with a new neighbor in their social network, and a new round would begin. The object that participants were trying to name was the same for the entire duration of the game and for all members of the game. An experimental trial concluded when all members completed the specified number of rounds. Participants did not have any information about the size of the population nor about the number of neighbors to whom they were connected nor even about which individuals they were interacting with in a given round. We explored the dynamics of convention formation over different network sizes between 24 and 96 and degrees of social connectedness. However, the controls within the experimental design ensured that the informational resources provided to subjects were identical across all conditions of the study.

Predictions and the brain: how musical sounds become rewarding

I want to point to the review article in Trends in Cognitive Science by Salimpoor, Zatorre, and collaborators  that outlines brain mechanisms underlying the pleasure we can feel on listening to music. (Motivated readers can request a copy of the article from me.)

•Dopamine release in mesolimbic reward circuits leads to reinforcement tied to predictions and outcomes. 

•Musical pleasure involves complex interactions between dopamine systems and cortical areas. 

•Individual variability in superior temporal cortex may explain varied musical preferences. 

•Cognitive, auditory, affective, and reward circuits interact to make music pleasurable. Music has always played a central role in human culture. 

The question of how musical sounds can have such profound emotional and rewarding effects has been a topic of interest throughout generations. At a fundamental level, listening to music involves tracking a series of sound events over time. Because humans are experts in pattern recognition, temporal predictions are constantly generated, creating a sense of anticipation. We summarize how complex cognitive abilities and cortical processes integrate with fundamental subcortical reward and motivation systems in the brain to give rise to musical pleasure. This work builds on previous theoretical models that emphasize the role of prediction in music appreciation by integrating these ideas with recent neuroscientific evidence.

(added note.... I just realized that I am repeating mention of the same article I pointed to in my more thorough Feb. 13 post! I guess the 72 year old brain is getting a bit forgetful.)

Hugging can make you less likely to catch a virus cold.

Daily social stress is known to correlate with susceptibility to cold virus infection. Cohen et al. ask whether social support and the actual receipt of physical touch during daily life—being hugged—attenuate the association of interpersonal stressors (social conflict) with subsequent risk for infection, cold signs, and clinical disease in response to an experimentally administered cold virus. They find, not surprisingly, that the answer is yes, consistent with numerous studies that have shown that social support boosts immune function. Here is their abstract:

Perceived social support has been hypothesized to protect against the pathogenic effects of stress. How such protection might be conferred, however, is not well understood. Using a sample of 404 healthy adults, we examined the roles of perceived social support and received hugs in buffering against interpersonal stress-induced susceptibility to infectious disease. Perceived support was assessed by questionnaire, and daily interpersonal conflict and receipt of hugs were assessed by telephone interviews on 14 consecutive evenings. Subsequently, participants were exposed to a virus that causes a common cold and were monitored in quarantine to assess infection and illness signs. Perceived support protected against the rise in infection risk associated with increasing frequency of conflict. A similar stress-buffering effect emerged for hugging, which explained 32% of the attenuating effect of support. Among infected participants, greater perceived support and more-frequent hugs each predicted less-severe illness signs. These data suggest that hugging may effectively convey social support.

Human language reveals a universal positivity bias

Dodds et al. have constructed 24 corpora (collections of writing) spread across 10 languages: English, Spanish, French, German, Brazilian Portuguese, Korean, Chinese (Simplified), Russian, Indonesian, and Arabic, including books, news outlets, social media, the, television and movie subtitles, and music lyrics. They note the most commonly used words, and how those words are perceived by individuals (on a happiness scale of 1-9) to provide a clear confirmation of the Pollyanna hypothesis suggested in 1969 by Boucher and Osgood - that there is a universal positivity bias in human communication. The authors illustrate the use of their "hedonometer", a language-based instrument for measuring expressed happiness, by constructing “happiness time series” for three famous works of literature, evaluated in their original languages of English, Russian, and French, respectively: Melville’s Moby Dick, Dostoyevsky’s Crime and Punishment, and Dumas’ The Count of Monte Cristo. Their abstract:

Using human evaluation of 100,000 words spread across 24 corpora in 10 languages diverse in origin and culture, we present evidence of a deep imprint of human sociality in language, observing that (i) the words of natural human language possess a universal positivity bias, (ii) the estimated emotional content of words is consistent between languages under translation, and (iii) this positivity bias is strongly independent of frequency of word use. Alongside these general regularities, we describe interlanguage variations in the emotional spectrum of languages that allow us to rank corpora. We also show how our word evaluations can be used to construct physical-like instruments for both real-time and offline measurement of the emotional content of large-scale texts.

Chickens count from the left, just like us!

Rugani et. al. show (Brugger's summary) that

...3-day old chicks associate small numerosities with the left side, and large ones with the right side, of a given space. The results show that newborn chicks can understand both relative and absolute quantities, and also suggest that the brain may be prewired in how it relates numbers to space. The work casts doubt on the importance of language and symbolic thought for the ability to represent discrete quantities larger than 3 and to develop a sense of numerical order and counting routines. Field studies of avian behavior have previously documented this ability in adult birds.

Abstract:

Humans represent numbers along a mental number line (MNL), where smaller values are located on the left and larger on the right. The origin of the MNL and its connections with cultural experience are unclear: Pre-verbal infants and nonhuman species master a variety of numerical abilities, supporting the existence of evolutionary ancient precursor systems. In our experiments, 3-day-old domestic chicks, once familiarized with a target number (5), spontaneously associated a smaller number (2) with the left space and a larger number (8) with the right space. The same number (8), though, was associated with the left space when the target number was 20. Similarly to humans, chicks associate smaller numbers with the left space and larger numbers with the right space.

More from Brugger's summary:

A more specific insight from Rugani et al.'s study is that a chick's sense of numerical order is tightly coupled with its sense of space: “More than” is equivalent to “to the right of.” This leads to a left-to-right directionality in the mapping of numbers to space—a finding that puts several previous proposals for the origin of mental number lines into perspective. One reason why researchers have assumed that this kind of numerical mapping is an invention of the human mind is its cultural modification. In cultures with a left-to-right reading and writing direction, the number line expands from left to right, but cultures with an opposite directional handling of script align numbers from right to left. Obviously, reading/writing direction cannot be the ultimate cause of directionality, nor can finger-counting habits. Presumably, the predominant role of the right hemisphere for numerical ordering biases initial attention to the left side of both physical and number space. Together with a preference for increasing over decreasing order—already apparent in 4-month-old human infants—the biological default of a number line would point from left to right.

The high from nicotine depends on whether you think it is there.

Fascinating observations from Gu et al.:

Significance

Nicotine is the primary addictive substance in tobacco, which stimulates neural pathways mediating reward processing. However, pure biochemical explanations are not sufficient to account for the difficulty in quitting and remaining smoke-free among smokers, and in fact cognitive factors are now considered to contribute critically to addiction. Using model-based functional neuroimaging, we show that smokers’ prior beliefs about nicotine specifically impact learning signals defined by principled computational models of mesolimbic dopamine systems. We further demonstrate that these specific changes in neural signaling are accompanied by measurable changes in smokers’ choice behavior. Our findings suggest that subjective beliefs can override the physical presence of a powerful drug like nicotine by modulating learning signals processed in the brain’s reward system.

Abstract

Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers’ prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers’ beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of “no nicotine in cigarette” (compared with “nicotine in cigarette”) strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers’ choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems.

Immune cells drive resilience to stress.

Evidence has been accumulating recently for back and forth interactions between the brain and immune system. Brachman et al. have now made the observation that lymphocytes isolated from stressed out mice, when transferred to naive mice, reduce anxiety and depression like behaviors in the naive mice. It would be interesting to see if a similar sort of transfer in humans had the same effect.

We examined whether cells of the adaptive immune system retain the memory of psychosocial stress and thereby alter mood states and CNS function in the host. Lymphocytes from mice undergoing chronic social defeat stress or from unstressed control mice were isolated and adoptively transferred into naive lymphopenic Rag2−/− mice. Changes in affective behavior, hippocampal cell proliferation, microglial activation states, and blood cytokine levels were examined in reconstituted stress-naive mice. The mice receiving lymphocytes from defeated donors showed less anxiety, more social behavior, and increased hippocampal cell proliferation compared with those receiving no cells or cells from unstressed donors. Mice receiving stressed immune cells had reduced pro-inflammatory cytokine levels in the blood relative to the other groups, an effect opposite to the elevated donor pro-inflammatory cytokine profile. Furthermore, mice receiving stressed immune cells had microglia skewed toward an anti-inflammatory, neuroprotective M2-like phenotype, an effect opposite the stressed donors' M1-like pro-inflammatory profile. However, stress had no effect on lymphocyte surface marker profiles in both donor and recipient mice. The data suggest that chronic stress-induced changes in the adaptive immune system, contrary to conferring anxiety and depressive behavior, protect against the deleterious effects of stress. Improvement in affective behavior is potentially mediated by reduced peripheral pro-inflammatory cytokine load, protective microglial activity, and increased hippocampal cell proliferation. The data identify the peripheral adaptive immune system as putatively involved in the mechanisms underlying stress resilience and a potential basis for developing novel rapid-acting antidepressant therapies.

MindStuff: A Guide for the Curious User

When I am trying to collect together some ideas to form a lecture or longer piece of work, I frequently think “Haven’t I seen that before?” …. and sure enough I find the ideas better put together in a previous essay I’ve done than in my current effort. I’ve just gone back and read through my 2005 web essay: MindStuff: A guide for the curious user. My reaction is the same as when last summer’s Chaos seminar group discussed the last chapter of my Biology of Mind Book. I think to myself, “Did I really write this? This is good stuff…” While there are a number of places I would tweak and update the text, the MindStuff essay still provides fundamental and useful information, particularly the “The Guide” section that starts halfway through the essay. The purpose of this post is just to point to the text.

The neurochemistry of music.

I want to point to an interesting review article by Chanda and Levitin, that summaries studies showing how music engages four of our bodies' fundamental neurochemical systems. I pass on the abstract and the start of the introduction to the article to give you an idea of its scope:

Music is used to regulate mood and arousal in everyday life and to promote physical and psychological health and well-being in clinical settings. However, scientific inquiry into the neurochemical effects of music is still in its infancy. In this review, we evaluate the evidence that music improves health and well-being through the engagement of neurochemical systems for (i) reward, motivation, and pleasure; (ii) stress and arousal; (iii) immunity; and (iv) social affiliation. We discuss the limitations of these studies and outline novel approaches for integration of conceptual and technological advances from the fields of music cognition and social neuroscience into studies of the neurochemistry of music. 

Introduction 

Music is one of a small set of human cultural universals, evoking a wide range of emotions, from exhilaration to relaxation, joy to sadness, fear to comfort, and even combinations of these. Many people use music to regulate mood and arousal, much as they use caffeine or alcohol. Neurosurgeons use it to enhance concentration, armies to coordinate movements and increase cooperation, workers to improve attention and vigilance, and athletes to increase stamina and motivation.

The notion that ‘music is medicine’ has roots that extend deep into human history through healing rituals practiced in pre-industrial, tribal-based societies. In contemporary society, music continues to be used to promote health and well-being in clinical settings, such as for pain management, relaxation, psychotherapy, and personal growth. Although much of this clinical use of music is based on ad hoc or unproven methods, an emerging body of literature addresses evidence-based music interventions through peer-reviewed scientific experiments. In this review, we examine the scientific evidence supporting claims that music influences health through neurochemical changes in the following four domains:

(i) reward, motivation and pleasure 

(ii) stress and arousal 

(iii) immunity 

(iv) social affiliation.

These domains parallel, respectively, the known neurochemical systems of

(i) dopamine and opioids 

(ii) cortisol, corticotrophin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) 

(iii) serotonin and the peptide derivatives of proopiomelanocortin (POMC), including alpha-melanocyte stimulating hormone and beta-endorphin 

(iv) oxytocin.

Although the evidence is often weak or indirect and all studies suffer from important limitations, the reviewed evidence does provide preliminary support for the claim that neurochemical changes mediate the influence of music on health.

Twitter predicts mortality from heart disease!

Here is an interesting item from Eichstaedt, Seligman, and collaborators:

Hostility and chronic stress are known risk factors for heart disease, but they are costly to assess on a large scale. We used language expressed on Twitter to characterize community-level psychological correlates of age-adjusted mortality from atherosclerotic heart disease (AHD). Language patterns reflecting negative social relationships, disengagement, and negative emotions—especially anger—emerged as risk factors; positive emotions and psychological engagement emerged as protective factors. Most correlations remained significant after controlling for income and education. A cross-sectional regression model based only on Twitter language predicted AHD mortality significantly better than did a model that combined 10 common demographic, socioeconomic, and health risk factors, including smoking, diabetes, hypertension, and obesity. Capturing community psychological characteristics through social media is feasible, and these characteristics are strong markers of cardiovascular mortality at the community level.

Metacognitive mechanisms underlying lucid dreaming.

Metacognition is the ability to observe, reflect on, and report one's own mental states during wakefulness. Dreaming is not typically accessible to this kind of monitoring, except in people who are lucid dreamers, aware that they are dreaming while in the sleep state (I can do this). Filevich et al. have looked for relationships between the neural correlates of lucid dreaming and thought monitoring:

Lucid dreaming is a state of awareness that one is dreaming, without leaving the sleep state. Dream reports show that self-reflection and volitional control are more pronounced in lucid compared with nonlucid dreams. Mostly on these grounds, lucid dreaming has been associated with metacognition. However, the link to lucid dreaming at the neural level has not yet been explored. We sought for relationships between the neural correlates of lucid dreaming and thought monitoring.

Human participants completed a questionnaire assessing lucid dreaming ability, and underwent structural and functional MRI. We split participants based on their reported dream lucidity. Participants in the high-lucidity group showed greater gray matter volume in the frontopolar cortex (BA9/10) compared with those in the low-lucidity group. Further, differences in brain structure were mirrored by differences in brain function. The BA9/10 regions identified through structural analyses showed increases in blood oxygen level-dependent signal during thought monitoring in both groups, and more strongly in the high-lucidity group.

Our results reveal shared neural systems between lucid dreaming and metacognitive function, in particular in the domain of thought monitoring. This finding contributes to our understanding of the mechanisms enabling higher-order consciousness in dreams.

The neuroscience of motivated cognition.

I want to point to this interesting open source article by Hughes and Zaki, who review research from social psychology and cognitive neuroscience that provides insight into the structure of motivated cognition (that can bias or distort reality), suggesting that it pervades information processing and is often effortless. Here are the opening paragraphs:

People often believe that their thinking aims squarely at gaining an accurate impression of reality. Upon closer inspection, this assumption collapses. Instead, like the inhabitants of Garrison Keillor's Lake Woebegon, individuals often see themselves and close others as possessing unrealistically high levels of positive attributes such as likeability, morality, and attractiveness. This bias persists among individuals who should know better: over 90% college professors believe their work is better than that of their peers, CIA analysts overestimate the accuracy of their predictions for future events, and doctors overconfidently estimate their medical knowledge.

These cases exemplify the phenomenon of motivated cognition, by which the goals and needs of individuals steer their thinking towards desired conclusions. A variety of motivations pervasively shapes cognition. For example, people wish to live in a coherent and consistent world. This leads people to recognize patterns where there are none, perceive control over random events, and shift their attitudes to be consistent with their past behaviors. People also need to feel good about themselves and about others with whom they identify. As such, people often self-enhance, evaluating themselves as having more desirable personalities and rosier future prospects than their peers, and taking personal credit for successes, but not failures. People likewise elevate their relationship partners and in-group members (e.g., people who share their political affiliation) in demonstrably unrealistic ways. Motivations can also have the opposite effect, leading people to derogate out-group members, even when the lines that divide ‘us’ from ‘them’ are defined de novo by researchers.

The authors follow this by noting studies demonstrating motivated cognition in perception, attention, decision making, etc.