Tuesday, September 02, 2014

Intergenerational transmission of emotional trauma.

Interesting work from Debiec and Sullivan on how conditioned fear learning in a parent is transmitted to children:

Despite clinical evidence that specific fear is transmitted across generations, we have little understanding of mechanisms. Here, we model social transmission of mother-to-infant fear in rodents. We show that maternal fear responses to a conditioned fear odor are sufficient to induce robust fear learning throughout infancy, with robust retention. Assessment of mechanism showed that maternal fear expression increases pups’ stress hormone corticosterone and amygdala activation to induce this cue-specific fear learning. Suppressing pups’ amygdala or preventing pups from mounting a stress response blocked this fear learning. Specific fears may thus be transferred across generations through maternal emotional communication and infant’s associative learning mechanisms. Elucidating the mechanisms of this transmission may inform the development of novel therapeutic and preventive approaches.

Monday, September 01, 2014

How could language have evolved?

An eminent group of co-authors (Bolhuis, Tattersall, Chomsky, and Berwick) suggest that a simple core repeatable operation is the basis of all language. This open source article is a "must read" item for anyone interested in the structure and evolution of language, and I pass on just the abstract and a bit on the basic model:

The evolution of the faculty of language largely remains an enigma. In this essay, we ask why. Language's evolutionary analysis is complicated because it has no equivalent in any nonhuman species. There is also no consensus regarding the essential nature of the language “phenotype.” According to the “Strong Minimalist Thesis,” the key distinguishing feature of language (and what evolutionary theory must explain) is hierarchical syntactic structure. The faculty of language is likely to have emerged quite recently in evolutionary terms, some 70,000–100,000 years ago, and does not seem to have undergone modification since then, though individual languages do of course change over time, operating within this basic framework. The recent emergence of language and its stability are both consistent with the Strong Minimalist Thesis, which has at its core a single repeatable operation that takes exactly two syntactic elements a and b and assembles them to form the set {a, b}.
...it appears that human language syntax can be defined in an extremely simple way that makes conventional evolutionary explanations much simpler. In this view, human language syntax can be characterized via a single operation that takes exactly two (syntactic) elements a and b and puts them together to form the set {a, b}. We call this basic operation “merge”. The “Strong Minimalist Thesis” (SMT) holds that merge along with a general cognitive requirement for computationally minimal or efficient search suffices to account for much of human language syntax. The SMT also requires two mappings: one to an internal conceptual interface for thought and a second to a sensory-motor interface that externalizes language as speech, sign, or other modality. The basic operation itself is simple. Given merge, two items such as the and apples are assembled as the set {the, apples}. Crucially, merge can apply to the results of its own output so that a further application of merge to ate and {the, apples} yields the set {ate, {the, apples}}, in this way deriving the full range of characteristic hierarchical structure that distinguishes human language from all other known nonhuman cognitive systems.

Friday, August 29, 2014

The origins of morality.

Mark Johnson has generated some creative and seminal ideas in his books "The Body in the Mind: The Bodily Basis of Meaning, Imagination, and Reason" and, with George Lakoff "Metaphors We Live By." I pass on a few clips from Les Beldo's review of his most recent book, "Morality for Humans Ethical Understanding from the Perspective of Cognitive Science":

Over the past 25 years, a growing number of cognitive scientists have taken it as their mission to find an empirical basis within brain science for the distinctive character of moral judgments. Investigators such as Marc Hauser, Steven Pinker, and Jonathan Haidt have posited the existence of an innate, domain-specific moral faculty in humans, be it a “universal moral grammar,” a “moral instinct,” or an “intuitive ethics.”
In Morality for Humans, Mark Johnson introduces an approach he calls “moral naturalism.” It is committed to the idea that moral knowledge does not exist on some separate plane but rather in the everyday habits, practices, institutions, and “bio-regulation” of lived organisms. Johnson is skeptical, however, of claims about the existence of a moral module in the human brain. He notes that “there are simply far too many complexly interacting multifunctional systems … in our intuitive moral judgments for there to be anything remotely resembling a distinct moral faculty.” Although he never uses the term, Johnson argues that moral problem-solving relies entirely on cognitive processes like logic, empathy, or narration. He sees the idea of an innate moral faculty as just another attempt to prove the existence of immutable moral laws, not in divine will or in pure reason but in a strong normative reading of cognitive science and evolutionary biology.
Johnson locates the source of values in our social and biological needs, cultural representations, and personal experiences. Here, Johnson has no qualms about violating the so-called naturalistic fallacy, which suggests that normative statements about how things ought to be cannot be derived from factual statements about what is. He moves freely between descriptions of human needs and human tendencies, on the one hand, and the normative suggestion that we ought to fulfill those needs and support those tendencies. Dismissing the naturalistic fallacy is easy if one thinks of it as an esoteric philosophical concept. But the term refers to a real logical problem of which Johnson is in fact acutely aware: “the fact that we have come to value certain states of affairs,” he writes, “is no guarantee that we should value them in the way we do.” This has been a particular weakness of studies that would make normative claims based on findings in cognitive neuroscience. How can descriptions of how our brains work tell us anything about what we ought to do in particular situations? It is a problem Johnson never resolves.
Morality is typically distinguished from other domains of social judgment by its unconditionality. A moral judgment refers to something that is considered right or wrong in and of itself. Johnson rejects the idea that moral judgments are unconditional, saying instead that the “trumping force” of morality owes to the fact that “certain things tend to matter more for us because they are thought to be necessary for the well-being of ourselves and others.” Individual well-being and societal cohesion are practical ends, however, and concerns about achieving them are matters of prudent conduct and prudent governance. This, along with Johnson's repeated insistence that moral problem-solving is no different in kind from any other form of problem-solving, leads one to wonder why he bothers to retain the concept of “morality” at all. Johnson suggests that values exist only in relation to some predefined or agreed-upon set of goods, feelings, or human needs, but that still creates fertile ground for hypothetical imperatives that are binding upon anyone who accepts the most basic premises of society. Why is this not enough? Is the stigma of moral relativism so frightening? What's so bad about prudence?

Thursday, August 28, 2014

The stability of the authoritarian state.

Science Magazine publishes comment on a fascinating article by King et al. who essentially reverse-engineer censorship in China to show that criticisms of the state, its leaders, and their policies are published, whereas posts about real-world events with collective action potential are censored. Criticism on the web, which was thought to be censored, is used by Chinese leaders to determine which officials are not doing their job of mollifying the people and need to be replaced. Here is the structured abstract from the article:

Censorship has a long history in China, extending from the efforts of Emperor Qin to burn Confucian texts in the third century BCE to the control of traditional broadcast media under Communist Party rule. However, with the rise of the Internet and new media platforms, more than 1.3 billion people can now broadcast their individual views, making information far more diffuse and considerably harder to control. In response, the government has built a massive social media censorship organization, the result of which constitutes the largest selective suppression of human communication in the recorded history of any country. We show that this large system, designed to suppress information, paradoxically leaves large footprints and so reveals a great deal about itself and the intentions of the government.
Rationale
Chinese censorship of individual social media posts occurs at two levels: (i) Many tens of thousands of censors, working inside Chinese social media firms and government at several levels, read individual social media posts, and decide which ones to take down. (ii) They also read social media submissions that are prevented from being posted by automated keyword filters, and decide which ones to publish.
To study the first level, we devised an observational study to download published Chinese social media posts before the government could censor them, and to revisit each from a worldwide network of computers to see which was censored. To study the second level, we conducted the first largescale experimental study of censorship by creating accounts on numerous social media sites throughout China, submitting texts with different randomly assigned content to each, and detecting from a worldwide network of computers which ones were censored.
To find out the details of how the system works, we supplemented the typical current approach (conducting uncertain and potentially unsafe confidential interviews with insiders) with a participant observation study, in which we set up our own social media site in China. While also attempting not to alter the system we were studying, we purchased a URL, rented server space, contracted with Chinese firms to acquire the same software as used by existing social media sites, and—with direct access to their software, documentation, and even customer service help desk support—reverseengineered how it all works.
Results
Criticisms of the state, its leaders, and their policies are routinely published, whereas posts with collective action potential are much more likely to be censored—regardless of whether they are for or against the state (two concepts not previously distinguished in the literature). Chinese people can write the most vitriolic blog posts about even the top Chinese leaders without fear of censorship, but if they write in support of or opposition to an ongoing protest—or even about a rally in favor of a popular policy or leader—they will be censored.
We clarify the internal mechanisms of the Chinese censorship apparatus and show how changes in censorship behavior reveal government intent by presaging their action on the ground. That is, it appears that criticism on the web, which was thought to be censored, is used by Chinese leaders to determine which officials are not doing their job of mollifying the people and need to be replaced.
Conclusion
Censorship in China is used to muzzle those outside government who attempt to spur the creation of crowds for any reason—in opposition to, in support of, or unrelated to the government. The government allows the Chinese people to say whatever they like about the state, its leaders, or their policies, because talk about any subject unconnected to collective action is not censored. The value that Chinese leaders find in allowing and then measuring criticism by hundreds of millions of Chinese people creates actionable information for them and, as a result, also for academic scholars and public policy analysts.

Wednesday, August 27, 2014

Early life anxiety in monkeys and humans correlates with connectivity between prefrontal cortex and amygdala.

A group of collaborators, mainly at the University of Wisconsin, including Ned Kalin and Richard Davidson, provide new information about the evolutionarily conserved brain network underlying extreme early-life anxiety:

Some individuals are endowed with a biology that renders them more reactive to novelty and potential threat. When extreme, this anxious temperament (AT) confers elevated risk for the development of anxiety, depression and substance abuse. These disorders are highly prevalent, debilitating and can be challenging to treat. The high-risk AT phenotype is expressed similarly in children and young monkeys and mechanistic work demonstrates that the central (Ce) nucleus of the amygdala is an important substrate. Although it is widely believed that the flow of information across the structural network connecting the Ce nucleus to other brain regions underlies primates’ capacity for flexibly regulating anxiety, the functional architecture of this network has remained poorly understood. Here we used functional magnetic resonance imaging (fMRI) in anesthetized young monkeys and quietly resting children with anxiety disorders to identify an evolutionarily conserved pattern of functional connectivity relevant to early-life anxiety. Across primate species and levels of awareness, reduced functional connectivity between the dorsolateral prefrontal cortex, a region thought to play a central role in the control of cognition and emotion, and the Ce nucleus was associated with increased anxiety assessed outside the scanner. Importantly, high-resolution 18-fluorodeoxyglucose positron emission tomography imaging provided evidence that elevated Ce nucleus metabolism statistically mediates the association between prefrontal-amygdalar connectivity and elevated anxiety. These results provide new clues about the brain network underlying extreme early-life anxiety and set the stage for mechanistic work aimed at developing improved interventions for pediatric anxiety.


Homologous dorsolateral prefrontal cortex (dlPFC) subdivisions show decreased intrinsic connectivity with the central (Ce) nucleus in anxious children and monkeys. (a) Children with anxiety disorders at rest. Bottom-left panel shows the Ce nucleus seed (cyan in red ring). Upper-left panel depicts a coronal slice through the human dlPFC cluster (dark orange; corrected for the combined volume of the mPFC and right dlPFC; n.s. when corrected for the volume of the whole brain). The intermediate frontal sulcus (IFS) is shown in dark red. Upper-right panel shows the IFS with the location of the coronal slice indicated by the blue vertical line. Bottom-right panel shows the location of the dlPFC cluster relative to the architectonic subdivisions of the human dlPFC. (b) Young monkeys with high levels of anxious temperament (AT) under anesthesia. Conventions are similar to a; dark red indicates the location of the sulcus principalis. The bottom-right panels of this figure were adapted with permission from Badre and D'Esposito.74 L, left hemisphere; R, right hemisphere.

Tuesday, August 26, 2014

More on better living through zapping your brain.

Anna Altman has done an entertaining piece on transcranial direct-current stimulation, or tDCS, which I have mentioned in numerous previous mindblog posts (enter tDCS in the mindblog search box). You can make your own tDCS machine from parts obtained at Radio Shack for ~ $20 or buy one off the web for $90. Various reports have shown enhanced alertness and learning, and palliative medical effect on chronic pain, stroke rehabilitation, and depressive disorders. Researchers go to lengths to warm of the potential downside effect of DIY (do it yourself) public experimentation. And indeed, so what if tDCS gives a bit of a boost?..

“Is brain boosting a fair addition to the cognitive enhancement arms race? Will it create a Morlock/Eloi-like social divide where the rich can afford to be smarter and leave everyone else behind? Will Tiger Moms force their lazy kids to strap on a zappity helmet during piano practice?” Or, she asks, “Could school-age girls use the zappy cap while studying math to drown out the voices that tell them they can’t do math because they’re girls?”

Monday, August 25, 2014

Origins of good and evil in human babies.

Felix Warneken does a review in TICS (Trends in Cognitive Sciences) of Paul Bloom new book "Just Babies: The Origins of Good and Evil," which argues that humans, already in the first year of life, have a basic moral sense that is shaped by innate evolved processes.

Bloom...reviews studies in which babies can choose to touch one of two geometrically shaped agents with googly eyes – and they prefer to touch one who helps a struggling fellow up a hill rather than one who pushes that fellow down. This indicates that babies like helping and despise harming others, even if they are only a third party who observes how other people treat each other. Beyond their judgments of the actions of others, young children also display helpful tendencies in their own behavior. Bloom reviews the extensive work on toddlers as young as 18 months of age who display a tendency to comfort others who are in distress, and spontaneously help clumsy people by picking up dropped objects and holding doors open. Last but not least, preschool children seem to have a sense of fairness when faced with the task of divvying up desirable resources, with equality already serving as a guiding principle.
...although our basic, parochially bound moral sentiments come naturally to us without much effort, applying these principles to strangers takes some mental effort. It requires that we employ perspective-taking in our interactions with others...Expanding our moral circle to include strangers thus depends on socialization and abilities that develop only in late childhood...our evolutionarily evolved morality is prepared for kin and friends, but not for strangers. This can be seen in young children's ingroup biases and toddlers’ stranger anxiety.
Still,
...human children depend more on interactions beyond the immediate family than do our closest evolutionary relatives... Infants thus have to tolerate being handed around and interact with many unfamiliar people from early on. We might therefore expect infants to be open-minded and vigilant at the same time, creating their social circles in a more sophisticated manner than ducklings who follow either white feathers or men with white beards, whichever they see first. And it seems as if they do so, not in a naïve fashion, but in a sophisticated way that balances risk and opportunity.

Friday, August 22, 2014

OhMyGawd...now MRI measurement are going to tell us how happy we are??

Dolan and collaborators come up with yet another clever use of MRI measurements. (If you enter "Dolan" in the mindblog search box, you will find numerous posts on his work.) The article appears to be open-source, which means I'm not going to pass on some of the eye-catching graphics (showing predictive activity in the striatum and right anterior insula) that you should be able to check out, along with the details of the experiment that recruited over 18,000 participants to play a smartphone gambling game and report their subjective happiness when queried.

A common question in the social science of well-being asks, “How happy do you feel on a scale of 0 to 10?” Responses are often related to life circumstances, including wealth. By asking people about their feelings as they go about their lives, ongoing happiness and life events have been linked, but the neural mechanisms underlying this relationship are unknown. To investigate it, we presented subjects with a decision-making task involving monetary gains and losses and repeatedly asked them to report their momentary happiness. We built a computational model in which happiness reports were construed as an emotional reactivity to recent rewards and expectations. Using functional MRI, we demonstrated that neural signals during task events account for changes in happiness.

Thursday, August 21, 2014

The source of consciousness.

Paller and Suzuki do a compact review on efforts to define the source of consciousness, arguing against the mysterian position that consciousness is beyond the scope of human understanding. They suggest that this position is like many other flaws in our common intuitions about consciousness. One of these is that if you direct your attention to something you must be aware of it. Not so, as this motion-induced blindness example demonstrates when you focus your attention on the central dot, with three surrounding yellow dots:



(to convince yourself the disappearing yellow dots are in fact always there enlarge the graphic to full screen and simply look at the wall or view beyond your tablet or monitor, perhaps scanning it back and forth, while letting the yellow dots remain in your peripheral vision.)

If paying attention doesn't guarantee awareness (as is the case in blindsight - in which objects can be discriminated without awareness of seeing them), what is the crucial ingredient? Current work suggests that exchange of information between specific cortical areas seems to be essential.

A clip:

The awareness we each have of our own body and our place in the world seems to be distinctly natural and fundamental. Yet the conscious experience of having a body can be bizarrely disrupted in patients with right parietal damage, who sometimes deny ownership of an entire arm. The rubber-hand illusion is another striking phenomenon, whereby seeing someone rubbing a fake hand while feeling the simultaneous tactile sensation on your own hand momentarily makes you feel that the fake hand is yours. In an even more extreme way, altered neural activity can produce an out-of-body experience.
These unusual perceptual experiences are no less ‘real’ than the sensation of a self inside a body. This standard way we each think of our self is a manufactured sensation, learned on the basis of sensory relationships across modalities. Awareness of a self inhabiting a body is not as obligatory as it seems: it is likely to have evolved for a behavioral advantage.
Why does the brain construct the sensation of a self inside a body? One answer appeals to the idea that you fare better in a social environment when you can attend to your own needs and predict what will happen next, including what other people are going to do. To make this work, specific brain mechanisms evolved to construct models of the attention and intentions of others and to localize them in the corresponding people's heads. The social neuroscience theory of consciousness [see my post on Graziano's ideas] postulates that these same brain mechanisms were adapted to construct a model of one's own attention and intentions, localized in one's own head and perceived as consciousness. If so, a primary function of consciousness is to allow us to predict our own behavior.
Another fragment of text:
...the neural processes that generate the subjective timing of a conscious decision that is seemingly instantaneous may be separate from the more protracted, unconscious processes that generate the content of the decision. The feeling of freely deciding at the precise time of our choosing may be a widespread illusion, albeit a beneficial one that promotes moral behavior and helps us to flourish as social beings.
Finally,
When we recognize the shortcomings of common assumptions about consciousness, we are in a better position to develop an integrative understanding of the origin, evolution, development, and subjectivity of consciousness. Instead of emphasizing a single paradigm for examining awareness, we can be enriched by enlisting a variety of approaches, combining functional, biological, social, and computational perspectives.


Wednesday, August 20, 2014

Is our microbiome manipulating us to look out for itself?

Links between our gut and our brain, especially via the vagus nerve, can regulate stress disorders such as depression and anxiety. Growing evidence shows that the microbes in our gut can influence this by releasing various neurotransmitters (like dopamine and serotonin) near the rich bed of nerve endings that surround the gut. A lactobacillus found in Yoghurt can alter the GABA inhibitory neurotransmitter system and reduce stress induced behaviors in mice, an effect that requires the intact vagus nerve. I would suggest you have a look at Zimmer's summary of work suggesting that gut bacteria, in addition to helping to break down our food, fight off infections and nurture our immune system, might be a puppet master altering our food preferences to benefit themselves. In mice, bacteria can alter levels of hormones that govern appetite. Possibly they could influence various food cravings in humans.

Tuesday, August 19, 2014

Brain and behavioral correlates of compassion training.

Davidson and colleagues at the University of Wisconsin have

...investigated whether short-term compassion training would enhance altruistic behavior toward a victim encountered outside of the training context. Altruistic behavior was assessed using the redistribution game, a novel economic decision-making task that models both unfair treatment of a victim and costly redistribution of funds to the victim.
Training consisted of practicing either compassion or reappraisal using guided audio instructions (via the Internet or compact disc) for 30 min per day for 2 weeks. Compassion trainees practiced cultivating feelings of compassion for different targets (a loved one, the self, a stranger, and a difficult person), and reappraisal trainees practiced reinterpreting personally stressful events to decrease negative affect. [note: in reappraisal training the psychological goal is self-focused (to decrease one’s own suffering) rather than other-focused (to decrease other people’s suffering through compassion).]
Here is their abstract:
Compassion is a key motivator of altruistic behavior, but little is known about individuals’ capacity to cultivate compassion through training. We examined whether compassion may be systematically trained by testing whether (a) short-term compassion training increases altruistic behavior and (b) individual differences in altruism are associated with training-induced changes in neural responses to suffering. In healthy adults, we found that compassion training increased altruistic redistribution of funds to a victim encountered outside of the training context. Furthermore, increased altruistic behavior after compassion training was associated with altered activation in brain regions implicated in social cognition and emotion regulation, including the inferior parietal cortex and dorsolateral prefrontal cortex (DLPFC), and in DLPFC connectivity with the nucleus accumbens. These results suggest that compassion can be cultivated with training and that greater altruistic behavior may emerge from increased engagement of neural systems implicated in understanding the suffering of other people, executive and emotional control, and reward processing.

Monday, August 18, 2014

Spooky and awesome technology

Recent issues of Science Magazine have amazing reports of technology advances: a brain-like spiking-neuron integrated circuit on a 5.4 billion transistor chip with 4096 neurosynaptic cores (Markoff does a nice summary in the NYTimes) - said to be as fundamental an advance as the invention of the first transistor;  a self assembling robot that forms itself from a flat sheet (see review by Chang); and, if that's not enough for you, what about self-assembling hordes of mini robots.  (How long will it be before these treats become parts of weapons systems that find their way into the hands of tribal jihadists, like the current U.S. high-tech weaponry being used by the Islamic State of Iraq and Syria?).

I won't reproduce the article abstracts here, but pass on three visuals:

First the new "True North" computer chip:


Second, a video of the self assembling robot.

   


And finally, Programmable self-assembly in a thousand-robot swarm.


Friday, August 15, 2014

More on brain games and training - and reversing cognitive decline in aging.

Yesterday I got into playing again with a subscription to the online brain training games developed by Michael Merzenich and his colleagues that I purchased about a year ago. (Merzenich was one of the researchers to find that the adult brain was plastic, could re-wire itself). I have engaged these brain games episodically, but being a lazy person not much motivated by their efforts to urge users on, have each time drifted away. After about twenty minutes of getting into the various games I can feel what must be the brain equivalent of muscle fatigue. An almost-headache, a growing sense of effort, and finally a beginning to tire, slow down and falter. There is no question, however, about the beneficial effects - which I can feel for many days afterwards - of the exercises on my attention, brain speed, short term memory. Several studies have now shown that brain changes induced by training exercises like these can persist for months or years.

I thought I would pass on links to several articles in this area that have been languishing for a long time in my queue of potential post items.

Murphy reviews several studies of the use of vision training games in athletics.

Medeiros does an article in Wired Magazine on Merzenich.

And, Abbott summarizes Gazzaley's work on a game (NeuroRacer) that reverses age-related cognitive decline.

This game is still considered a research tool, and is not released for general use, but the Optic Flow: Navigation game on the http://www.brainhq.com/ site has similar features (simulated highway driving, noting and evaluating moving signs and obstacles).

Here is the abstract from the paper of Gazzaley and collaborators:

Cognitive control is defined by a set of neural processes that allow us to interact with our complex environment in a goal-directed manner. Humans regularly challenge these control processes when attempting to simultaneously accomplish multiple goals (multitasking), generating interference as the result of fundamental information processing limitations. It is clear that multitasking behaviour has become ubiquitous in today’s technologically dense world, and substantial evidence has accrued regarding multitasking difficulties and cognitive control deficits in our ageing population. Here we show that multitasking performance, as assessed with a custom-designed three-dimensional video game (NeuroRacer), exhibits a linear age-related decline from 20 to 79 years of age. By playing an adaptive version of NeuroRacer in multitasking training mode, older adults (60 to 85 years old) reduced multitasking costs compared to both an active control group and a no-contact control group, attaining levels beyond those achieved by untrained 20-year-old participants, with gains persisting for 6 months. Furthermore, age-related deficits in neural signatures of cognitive control, as measured with electroencephalography, were remediated by multitasking training (enhanced midline frontal theta power and frontal–posterior theta coherence). Critically, this training resulted in performance benefits that extended to untrained cognitive control abilities (enhanced sustained attention and working memory), with an increase in midline frontal theta power predicting the training-induced boost in sustained attention and preservation of multitasking improvement 6 months later. These findings highlight the robust plasticity of the prefrontal cognitive control system in the ageing brain, and provide the first evidence, to our knowledge, of how a custom-designed video game can be used to assess cognitive abilities across the lifespan, evaluate underlying neural mechanisms, and serve as a powerful tool for cognitive enhancement.

Thursday, August 14, 2014

How chronic pain saps our motivations and desires - the mechanism.

Fields gives a nice summary of work by Schwartz et al., who find a detailed synaptic mechanism for how chronic pain saps our motivations and desires. I pass on the article's abstract and a summary graphic by Schwartz.

Several symptoms associated with chronic pain, including fatigue and depression, are characterized by reduced motivation to initiate or complete goal-directed tasks. However, it is unknown whether maladaptive modifications in neural circuits that regulate motivation occur during chronic pain. Here, we demonstrate that the decreased motivation elicited in mice by two different models of chronic pain requires a galanin receptor 1–triggered depression of excitatory synaptic transmission in indirect pathway nucleus accumbens medium spiny neurons. These results demonstrate a previously unknown pathological adaption in a key node of motivational neural circuitry that is required for one of the major sequela of chronic pain states and syndromes.

Glutamate inputs excite nucleus accumbens medium spiny neurons. Chronic pain reduces AMPA receptor function in the DADR2-expressing class of these neurons, thereby reducing their activation by glutamate input. This decreases the motivation to work for a food reward.

Wednesday, August 13, 2014

The habenula (?) does a tally of our negative outcomes.

Impress your friends that you know the name of a brain region that they haven't heard of before! Lawson et al., in yet another publication that includes Raymond Dolan as one its authors, find that the habenula encodes the dynamically changing negative motivational value of stimuli that predict primary punishments. One suggestion is that an overactive habenula might cause the feelings of impending doom and low motivation common in people with depression.


Learning what to approach, and what to avoid, involves assigning value to environmental cues that predict positive and negative events. Studies in animals indicate that the lateral habenula encodes the previously learned negative motivational value of stimuli. However, involvement of the habenula in dynamic trial-by-trial aversive learning has not been assessed, and the functional role of this structure in humans remains poorly characterized, in part, due to its small size. Using high-resolution functional neuroimaging and computational modeling of reinforcement learning, we demonstrate positive habenula responses to the dynamically changing values of cues signaling painful electric shocks, which predict behavioral suppression of responses to those cues across individuals. By contrast, negative habenula responses to monetary reward cue values predict behavioral invigoration. Our findings show that the habenula plays a key role in an online aversive learning system and in generating associated motivated behavior in humans.

Tuesday, August 12, 2014

In learning, too much of a good thing can be bad.

Many contemporary elementary school classrooms have walls that are covered with varied and interesting displays that are not relevant to ongoing instruction (very unlike the austere and bare walls shown in photographs of the 1860 one room schoolhouse walls that now form the living room walls of my home on Twin Valley road in Middleton, WI.) Fisher et al. make the point that rich and distracting environments can detract from focused learning.

A large body of evidence supports the importance of focused attention for encoding and task performance. Yet young children with immature regulation of focused attention are often placed in elementary-school classrooms containing many displays that are not relevant to ongoing instruction. We investigated whether such displays can affect children’s ability to maintain focused attention during instruction and to learn the lesson content. We placed kindergarten children in a laboratory classroom for six introductory science lessons, and we experimentally manipulated the visual environment in the classroom. Children were more distracted by the visual environment, spent more time off task, and demonstrated smaller learning gains when the walls were highly decorated than when the decorations were removed.

Monday, August 11, 2014

Varieties of introspection.

I disagree with David Brooks’ opinions much of the time, but I’m impressed with what a polymath he is. His Op-Ed piece on healthy versus unhealthy introspection is a case in point:

...there seems to be a paradox at the heart of introspection. The self is something that can be seen more accurately from a distance than from close up. The more you can yank yourself away from your own intimacy with yourself, the more reliable your self-awareness is likely to be...When people examine themselves from too close, they often end up ruminating or oversimplifying...have repetitive thoughts, but don’t take action. Depressed ruminators end up making themselves more depressed.
We are better self-perceivers if we can create distance and see the general contours of our emergent system selves — rather than trying to unpack constituent parts. This can be done in several ways.
First, you can distance yourself by time. ...people who write about trauma later on can place a broader perspective on things. Their lives are improved by the exercise.
Second, we can achieve distance from self through language. ..it’s smart, when trying to counsel yourself, to pretend you are somebody else. This can be done a bit even by thinking of yourself in the third person...people who view themselves from a self-distanced perspective are better at adaptive self-reflection than people who view themselves from a self-immersed perspective.
Finally, there is narrative. ..We should see ourselves as literary critics, putting each incident in the perspective of a longer life story. The narrative form is a more supple way of understanding human processes, even unconscious ones, than rationalistic analysis.
Maturity is moving from the close-up to the landscape, focusing less on your own supposed strengths and weaknesses and more on the sea of empathy in which you swim, which is the medium necessary for understanding others, one’s self, and survival.

Friday, August 08, 2014

An opinion due to social conformity lasts only a few days.

Huang et al. do a study on 22 South China Normal University students in which they evaluated the attractiveness of a series of neutral faces with and without knowing other students' opinions of them.

When people are faced with opinions different from their own, they often revise their own opinions to match those held by other people. This is known as the social-conformity effect. Although the immediate impact of social influence on people’s decision making is well established, it is unclear whether this reflects a transient capitulation to public opinion or a more enduring change in privately held views. In an experiment using a facial-attractiveness rating task, we asked participants to rate each face; after providing their rating, they were informed of the rating given by a peer group. They then rerated the same faces after 1, 3, or 7 days or 3 months. Results show that individuals’ initial judgments are altered by the differing opinions of other people for no more than 3 days. Our findings suggest that because the social-conformity effect lasts several days, it reflects a short-term change in privately held views rather than a transient public compliance.

Thursday, August 07, 2014

Motivation not improved by multiple motives.

Wrzesniewski et al. do an interesting study of 11,320 West Point cadets over a period of ten years.

Although people often assume that multiple motives for doing something will be more powerful and effective than a single motive, research suggests that different types of motives for the same action sometimes compete. More specifically, research suggests that instrumental motives, which are extrinsic to the activities at hand, can weaken internal motives, which are intrinsic to the activities at hand. We tested whether holding both instrumental and internal motives yields negative outcomes in a field context in which various motives occur naturally and long-term educational and career outcomes are at stake. We assessed the impact of the motives of over 10,000 West Point cadets over the period of a decade on whether they would become commissioned officers, extend their officer service beyond the minimum required period, and be selected for early career promotions. For each outcome, motivation internal to military service itself predicted positive outcomes; a relationship that was negatively affected when instrumental motives were also in evidence. These results suggest that holding multiple motives damages persistence and performance in educational and occupational contexts over long periods of time.
Here is a bit more detail from the start of the results section:
Across two different survey measures administered by the institution at the start of their first year, cadets indicated how much each of a set of reasons offered represented their reasons for attending West Point, which allowed them to endorse any number of reasons at various levels of strength (response scales for the two measures ranged from very important to not important on a 1–3 Likert-type scale; and very positive to very negative on a 1–5 Likert-type scale). Reasons offered in the survey ranged from the prospect of getting a good job (instrumental), to economic necessity (cadets do not pay tuition), to a desire to be an Army officer (internal). Of the various reasons offered, two types were of key interest: reasons indicating an internal desire to become an Army officer and reasons indicating an instrumental desire to gain eventual outcomes associated with attending West Point. The data are archival; thus, none of the items in the surveys completed by cadets perfectly captured the distinction between “internal” and “instrumental” motives. For example, there were no items intended to capture a “pure” internal motive, defined to mean that the activity of becoming a West Point cadet was a meaningful and valuable end in itself (3). However, this motive is “internal” in the sense that the desire to be an Army officer requires that one do the things that Army officers do. In this way, it is akin to “being a soldier” (internal) rather than “getting a good job” (instrumental)....A total of 31 reasons appeared in the surveys and were subjected to exploratory factor analysis...

Wednesday, August 06, 2014

How much do our genes influence our political beliefs?

One of MindBlog’s subject threads has been noting articles that examine the correlation between our genetic constitution and our political behaviors. Thus I point to a recent article by Thomas Edsall that notes work in this controversial field by Ludeke et al. who:

...write that “authoritarianism, religiousness and conservatism,” which they call the “traditional moral values triad,” are “substantially influenced by genetic factors.” — all three traits are reflections of “a single, underlying tendency,” previously described in one word by Bouchard in a 2006 paper as “traditionalism.” Traditionalists in this sense are defined as “having strict moral standards and child-rearing practices, valuing conventional propriety and reputation, opposing rebelliousness and selfish disregard of others, and valuing religious institutions and practices.”
From this perspective, the Democratic Party — supportive of abortion rights, same-sex marriage and the primacy of self-expressive individualism over obligation to family — is irreconcilably alien to a segment of the electorate. And the same is true from the opposite viewpoint: a Republican Party committed to right-to-life policies, to a belief that marriage must be between a man and a woman, and to family obligation over self-actualization, is profoundly unacceptable to many on the left.
Ludeke et al. studied a sample of identical (monozygotic) and fraternal (dizygotic) twins who were separated from each other early in life. They assessed their adult social, political, and social attitudes, finding that they represented a single construct that was heritable and similar to a traditionalism measure. Their abstract:
Social attitudes, political attitudes and religiousness are highly inter-correlated. Furthermore, each is substantially influenced by genetic factors. Koenig and Bouchard (2006) hypothesized that these three areas (which they termed the Traditional Moral Values Triad) each derive from an underlying latent trait concerning the tendency to obey traditional authorities. We tested this hypothesis with data from a sample of twins raised in different homes. We assessed social attitudes with Altemeyer’s (1988) Right-Wing Authoritarianism scale, political attitudes with Wilson and Patterson’s (1968) Conservatism scale, and religiousness with Wiggins’ (1966) Religious Fundamentalism scale. The best-fitting model identified the three TMVT domains as different manifestations of a single latent and significantly heritable factor. Further, the genetic and environmental bases for this factor overlapped heavily with those for the Multidimensional Personality Questionnaire Traditionalism scale, supporting the conception of traditionalism as the latent factor represented by the three scales in contemporary Western societies.