Where the brain stores emotional memories

The brain mechanisms involved in forming fear memories associated with smells, sounds, and visual images are fairly well understood, but where these old fear memories are stored in the brain has not been as clear. Sacco and Sacchetti now show that these fear memories are stored in secondary, but not primary, sensory cortices - depending on whether the conditioned stimulus was visual, auditory, or olfactory. Only "old," not new, memories are stored in this way, and lesions of secondary cortices, while disrupting the old memories, do not prevent the acquisition of new memories. Here is their abstract:

Visual, acoustic, and olfactory stimuli associated with a highly charged emotional situation take on the affective qualities of that situation. Where the emotional meaning of a given sensory experience is stored is a matter of debate. We found that excitotoxic lesions of auditory, visual, or olfactory secondary sensory cortices impaired remote, but not recent, fear memories in rats. Amnesia was modality-specific and not due to an interference with sensory or emotional processes. In these sites, memory persistence was dependent on ongoing protein kinase M activity and was associated with an increased activity of layers II–IV, thus suggesting a synaptic strengthening of corticocortical connections. Lesions of the same areas left intact the memory of sensory stimuli not associated with any emotional charge. We propose that secondary sensory cortices support memory storage and retrieval of sensory stimuli that have acquired a behavioral salience with the experience.

Sex at Dawn

A recent Dan Savage column in The Onion pointed me to an interesting view of our modern sexual hangups. Ryan and Jetha in their book "Sex at Dawn" ask why monogamy and infidelity are such prominent issues in many societies. They argue that monogamy does not come naturally to our species, but rather is an imposition of the religious and cultural institutions that appeared with the advent of agriculture. These institutions, together with mainstream evolutionary psychology, maintain the conventional wisdom that men and women evolved in families where a man’s possessions and protection were exchanged for a woman’s fertility and fidelity. The authors maintain that this narrative is collapsing, and take a tour of evidence from anthropology, archeology, primatology, anatomy, and psychosexuality to offer data and arguments that our ancestors lived in egalitarian groups that shared food, child care, and often, sexual partners.

I downloaded the book for my Kindle, and found it an entertaining, spirited and engaging read, although it did have its share of inaccuracies, as well as some chaotic, repetitive and preachy sections. Their argument against the conventional evolutionary psychology view as a set of just-so stories is a common one. I would suggest that you glance at the excerpts from the book offered on their website to get an idea of bouncy tone of the prose.

The first church of robotics

Technology guru Jaron Lanier has provided a lucid NYTimes Op-Ed article on now we are misguided and damaged by thinking about increasingly intelligent machines as fellow creatures rather than tools. He sees an inappropriate new religion being expressed through engineering culture, which looses sight of the fact that technology is essentially a service. You should read the article. Here are some clips:

...the nuts and bolts of A.I. research can often be more usefully interpreted without the concept of A.I. at all. For example, I.B.M. scientists recently unveiled a “question answering” machine that is designed to play the TV quiz show “Jeopardy.” Suppose I.B.M. had dispensed with the theatrics, declared it had done Google one better and come up with a new phrase-based search engine. This framing of exactly the same technology would have gained I.B.M.’s team as much (deserved) recognition as the claim of an artificial intelligence, but would also have educated the public about how such a technology might actually be used most effectively.

On Robot Teachers:

...these robots are just a form of high-tech puppetry. The children are the ones making the transaction take place — having conversations and interacting with these machines, but essentially teaching themselves. This just shows that humans are social creatures, so if a machine is presented in a social way, people will adapt to it.

On the recommendations made by Netflix and Pandora:

...our exposure to art shouldn’t be hemmed in by an algorithm that we merely want to believe predicts our tastes accurately. These algorithms do not represent emotion or meaning, only statistics and correlations...while Silicon Valley might sell artificial intelligence to consumers, our industry certainly wouldn’t apply the same automated techniques to some of its own work. Choosing design features in a new smartphone, say, is considered too consequential a game. Engineers don’t seem quite ready to believe in their smart algorithms enough to put them up against Apple’s chief executive, Steve Jobs, or some other person with a real design sensibility.

On Simgularity University:

...The influential Silicon Valley institution preaches a story that goes like this: one day in the not-so-distant future, the Internet will suddenly coalesce into a super-intelligent A.I., infinitely smarter than any of us individually and all of us combined; it will become alive in the blink of an eye, and take over the world before humans even realize what’s happening.
...a great deal of the confusion and rancor in the world today concerns tension at the boundary between religion and modernity — whether it’s the distrust among Islamic or Christian fundamentalists of the scientific worldview, or even the discomfort that often greets progress in fields like climate change science or stem-cell research...If technologists are creating their own ultramodern religion, and it is one in which people are told to wait politely as their very souls are made obsolete, we might expect further and worsening tensions. But if technology were presented without metaphysical baggage, is it possible that modernity would not make people as uncomfortable?

Finally,

Technology is essentially a form of service. We work to make the world better. Our inventions can ease burdens, reduce poverty and suffering, and sometimes even bring new forms of beauty into the world. We can give people more options to act morally, because people with medicine, housing and agriculture can more easily afford to be kind than those who are sick, cold and starving...But civility, human improvement, these are still choices. That’s why scientists and engineers should present technology in ways that don’t confound those choices...We serve people best when we keep our religious ideas out of our work.

Similar brain cortex changes during human development and evolution

Hill et al. show that expansion of the human cortex during development involves the same brain areas that have changed the most in the evolutionary expansion from monkey to human brains.  They suggest that it is beneficial for regions of recent evolutionary expansion to remain less mature at birth, perhaps to increase the influence of postnatal experience on their development.

The cerebral cortex of the human infant at term is complexly folded in a similar fashion to adult cortex but has only one third the total surface area. By comparing 12 healthy infants born at term with 12 healthy young adults, we demonstrate that postnatal cortical expansion is strikingly nonuniform: regions of lateral temporal, parietal, and frontal cortex expand nearly twice as much as other regions in the insular and medial occipital cortex. This differential postnatal expansion may reflect regional differences in the maturity of dendritic and synaptic architecture at birth and/or in the complexity of dendritic and synaptic architecture in adults. This expression may also be associated with differential sensitivity of cortical circuits to childhood experience and insults. By comparing human and macaque monkey cerebral cortex, we infer that the pattern of human evolutionary expansion is remarkably similar to the pattern of human postnatal expansion. To account for this correspondence, we hypothesize that it is beneficial for regions of recent evolutionary expansion to remain less mature at birth, perhaps to increase the influence of postnatal experience on the development of these regions or to focus prenatal resources on regions most important for early survival.

Figure - Comparison of evolutionary and postnatal cortical surface expansion. (A) Map of regional evolutionary cortical expansion between an adult macaque and the average human adult (right hemisphere only). Evolution expansion scale indicates how many times larger the surface area is in humans relative to the corresponding area in the macaque. (B) Map of human postnatal cortical expansion for comparison. (C) Correlation map comparing postnatal to evolutionary cortical surface expansion.

We generalize negative more than positive stimuli

Schechtman et al. find that our learned response to a sound frequency associated with negative reinforcement generalizes over a broader range of adjacent frequencies (has a wider generalization curve) than the response to a positive reinforcement, both being greater than the response to a neutral stimulus. This 'better be safe than sorry' strategy makes sense in terms of survival, as noted in the author's introduction. They discuss the role of the amygdala, and suggest that individual differences in the effect that emotional valence has on generalization could underlie susceptibility to long-term effects of emotional events, possibly explaining why some people seem more susceptible to post-traumatic stress disorder (PTSD).:

If you are a dog, mistaking another dog bark for a lion roar is a shame—you might have missed a friend; but mistaking a roar for a bark can be fatal...Because a miss in this example is much more "costly" than a false-alarm, a more liberal bias for the loss-related stimulus can be expected.... in real-life, it is rarely the exact specific roar or specific bark you once heard, and stimuli rarely repeat with the exact physical properties with which they were first encountered. This means that the same logic used for immediate response should generalize to similar, yet not identical, sounds. We therefore hypothesized that valence associated with a stimulus during learning would influence the scope of generalization, and specifically, that stimuli that were previously associated with loss would generalize more than stimuli that were previously associated with gain.

Here is their abstract, followed by a graphic:

Learning includes the ability to generalize to new situations and respond to similar, yet not identical stimuli. We use stimulus generalization in humans to show that tones that were negatively reinforced induce wider generalization curves than tones that were positively reinforced, and these in turn induce wider curves than neutral memory. Importantly, these wider generalization curves persist even if outcomes for all tones are made identical, indicating that the learning induced a perceptual change, and not merely a decision bias. Moreover, it persists after taking into account loss-aversion, suggesting it is a result of valence per se, and not intensity that reflects overweighting of the aversive stimuli. This effect of emotional valence on learning suggests different locations of plasticity and network mechanisms in the brain. Particularly, it suggests that brain areas that mediate reinforcement and emotions are involved during the learning process to induce a neural representation that can support this broader behavioral generalization. In addition, these findings highlight a model for anxiety and trauma disorders in which aversive experiences affect more than they should, sometimes even in seemingly irrational situations.

Figure - The amount of generalization for negative (aversive), positive (rewarding), and no (neutral)—reinforcement... Average response rate in the generalization stage for tones in different distances from the tones that were reinforced during the acquisition stage.

Trying too hard....

Here is a nice short bit from Daniel Gilbert on how trying too hard makes us perform worse.

Are self-reflective people more depressed?

I've repeatedly heard in psychology seminars the truism that introspection (versus extroversion) correlates with depression. Grossmann and Kross, in their comparison of University of Michigan and Moscow State University students, show that this depends very much on culture. Gilbert Chin does a nice summary in the July 30 Science Magazine (picture credit: Vassilij Grivorovi Perov):

Dostoyevsky. For anyone steeped in the traditional canon of Western literature, his name elicits visions of bleak winters filled with contemplative despair. This common perception of Russian culture has fueled speculation about an underlying symbiosis between a predisposition to focus on negative feelings or experiences and a tendency toward depression. Grossmann and Kross have examined this purported linkage by contrasting self-reflective measures in Russians and Americans. Brooding correlated positively with depressive symptoms in University of Michigan students, but these were inversely related in students at Moscow State University even though the latter displayed a much greater propensity for rumination. Assessing the mode of self-reflection revealed that Russian students were more apt than Americans to examine their feelings from a third-person or observer's perspective, reconstruing the experiential details rather than recounting them from a first-person point of view. Distancing oneself in such a fashion mediated the opposite influences of American versus Russian cultures on the relation between self-reflection and negative affect.

The Web and the end of forgetting

I need to pass on a 'must read' article by Jeffrey Rosen that has been on my list of potential mindblog posts. He describes the impossibility of ever removing the traces of ourselves that we have left on the Web, and the social consequences of this fact. Here are just a few clips from his very thorough article:

...The end of the Western frontier led to worries that Americans could no longer seek a fresh start and leave their past behind, a kind of reinvention associated with the phrase “G.T.T.,” or “Gone to Texas.” But the dawning of the Internet age promised to resurrect the ideal of … the “protean self.” If you couldn’t flee to Texas, you could always seek out a new chat room and create a new screen name… What seemed within our grasp was a power that only Proteus possessed: namely, perfect control over our shifting identities…But the hope that we could carefully control how others view us in different contexts has proved to be another myth. As social-networking sites expanded, it was no longer quite so easy to have segmented identities: now that so many people use a single platform to post constant status updates and photos about their private and public activities, the idea of a home self, a work self, a family self and a high-school-friends self has become increasingly untenable….far from giving us a new sense of control over the face we present to the world, the Internet is shackling us to everything that we have ever said, or that anyone has said about us, making the possibility of digital self-reinvention seem like an ideal from a distant era.

ReputationDefender, which has customers in more than 100 countries, is the most successful of the handful of reputation-related start-ups that have been growing rapidly after the privacy concerns raised by Facebook and Google... For a fee, the company will monitor your online reputation, contacting Web sites individually and asking them to take down offending items. In addition, with the help of the kind of search-optimization technology that businesses use to raise their Google profiles, ReputationDefender can bombard the Web with positive or neutral information about its customers, either creating new Web pages or by multiplying links to existing ones to ensure they show up at the top of any Google search. ..By automatically raising the Google ranks of the positive links, ReputationDefender pushes the negative links to the back pages of a Google search, where they’re harder to find.

In the nearer future, Internet searches for images are likely to be combined with social-network aggregator search engines, like today’s Spokeo and Pipl, which combine data from online sources — including political contributions, blog posts, YouTube videos, Web comments, real estate listings and photo albums. Increasingly these aggregator sites will rank people’s public and private reputations, like the new Web site Unvarnished, a reputation marketplace where people can write anonymous reviews about anyone. In the Web 3.0 world, Fertik predicts, people will be rated, assessed and scored based not on their creditworthiness but on their trustworthiness as good parents, good dates, good employees, good baby sitters or good insurance risks.

Anticipating these challenges, some legal scholars have begun imagining new laws that could allow people to correct, or escape from, the reputation scores that may govern our personal and professional interactions in the future. Jonathan Zittrain, who teaches cyberlaw at Harvard Law School, supports an idea he calls “reputation bankruptcy,” which would give people a chance to wipe their reputation slates clean and start over. To illustrate the problem, Zittrain showed me an iPhone app called Date Check, by Intelius, that offers a “sleaze detector” to let you investigate people you’re thinking about dating — it reports their criminal histories, address histories and summaries of their social-networking profiles. Services like Date Check, Zittrain said, could soon become even more sophisticated, rating a person’s social desirability based on minute social measurements — like how often he or she was approached or avoided by others at parties (a ranking that would be easy to calibrate under existing technology using cellphones and Bluetooth). Zittrain also speculated that, over time, more and more reputation queries will be processed by a handful of de facto reputation brokers — like the existing consumer-reporting agencies Experian and Equifax, for example — which will provide ratings for people based on their sociability, trustworthiness and employability.

Jorge Luis Borges, in his short story “Funes, the Memorious,” describes a young man who, as a result of a riding accident, has lost his ability to forget. Funes has a tremendous memory, but he is so lost in the details of everything he knows that he is unable to convert the information into knowledge and unable, as a result, to grow in wisdom. Viktor Mayer-Schönberger, in “Delete,” uses the Borges story as an emblem for the personal and social costs of being so shackled by our digital past that we are unable to evolve and learn from our mistakes. After reviewing the various possible legal solutions to this problem, Mayer-Schönberger says he is more convinced by a technological fix: namely, mimicking human forgetting with built-in expiration dates for data. He imagines a world in which digital-storage devices could be programmed to delete photos or blog posts or other data that have reached their expiration dates, and he suggests that users could be prompted to select an expiration date before saving any data.

Good and Bad in the Hands of Politicians

Casasanto1 and Jasmin do an interesting study that shows a link between action and emotion, positive messages are more strongly associated with dominant hand gestures and negative messages with non-dominant hand gestures.

We analyzed speech and gesture (3012 spoken clauses, 1747 gestures) from the final debates of the 2004 and 2008 US presidential elections, which involved two right-handers (Kerry, Bush) and two left-handers (Obama, McCain). Blind, independent coding of speech and gesture allowed objective hypothesis testing. Right- and left-handed candidates showed contrasting associations between gesture and speech. In both of the left-handed candidates, left-hand gestures were associated more strongly with positive-valence clauses and right-hand gestures with negative-valence clauses; the opposite pattern was found in both right-handed candidates...The results suggest that the hand speakers use to gesture may have unexpected (and probably unintended) communicative value, providing the listener with a subtle index of how the speaker feels about the content of the co-occurring speech.

Deconstructing science blogs

Wow, I guess I didn't realize what I was missing because of my habit of largely ignoring other science blogs (Jonah Leher's outstanding "Frontal Cortex" blog excepted), preferring to spend my time trolling for original source articles. Virginia Heffernan describes a massive defection of bloggers from Seed Media's ScienceBlogs group, and her subsequent perusing of the group's blogging products. She says that she:

...discovered that ScienceBlogs has become preoccupied with trivia, name-calling and saber rattling. Maybe that’s why the ScienceBlogs ship started to sink.

Recently a blogger called GrrlScientist, on Living the Scientific Life (Scientist, Interrupted), expressed her disgust at the “flock of hugely protruding bellies and jiggling posteriors everywhere I go.” Gratuitous contempt like this is typical. Mark Hoofnagle on Denialism Blog sideswiped those who question antibiotics, writing, “their particular ideology requires them to believe in the primacy of religion (Christian Science, New Age Nonsense) or in the magical properties of nature.” Over at Pharyngula — which often ranks in the Top 100 blogs on the Internet— PZ Myers revels in sub-“South Park” blasphemy, presenting (in one recent stunt) his sketch of the Prophet Muhammad as a cow-pig hybrid excited about “raping a 9-year-old girl.”

Clearly I’ve been out of some loop for too long, but does everyone take for granted now that science sites are where graduate students, researchers, doctors and the “skeptical community” go not to interpret data or review experiments but to chip off one-liners, promote their books and jeer at smokers, fat people and churchgoers? And can anyone who still enjoys this class-inflected bloodsport tell me why it has to happen under the banner of science?

Hammering away at an ideology, substituting stridency for contemplation, pummeling its enemies in absentia: ScienceBlogs has become Fox News for the religion-baiting, peak-oil crowd. Though Myers and other science bloggers boast that they can be jerky in the service of anti-charlatanism, that’s not what’s bothersome about them. What’s bothersome is that the site is misleading. It’s not science by scientists, not even remotely; it’s science blogging by science bloggers. And science blogging, apparently, is a form of redundant and effortfully incendiary rhetoric that draws bad-faith moral authority from the word “science” and from occasional invocations of “peer-reviewed” thises and thats.

I think she overstates her case a bit, but I did take the time to scan some of the mentioned blogs, and indeed there was more gratuitous nastiness than I thought appropriate.

Speakers and Listeners - fMRI shows coupled brains

As a followup to Monday's post on mirror neurons, this fascinating study by Stephens et al. shows that brain activities in a speaker-listener pair are tightly coupled, and that the magnitude of activity in areas exhibiting predictive anticipatory responses correlates with understanding. The graphic summaries of fMRI data in this open access article are quite nice, and you might want to check them out. The MindBlog reader who pointed out this early PNAS publication to me wonders "Could their findings open a new window of how to interpret the "function" of "conscious self", with the conscious self as the evaluating "outpost" of the coupled companion.?"

Verbal communication is a joint activity; however, speech production and comprehension have primarily been analyzed as independent processes within the boundaries of individual brains. Here, we applied fMRI to record brain activity from both speakers and listeners during natural verbal communication. We used the speaker's spatiotemporal brain activity to model listeners’ brain activity and found that the speaker's activity is spatially and temporally coupled with the listener's activity. This coupling vanishes when participants fail to communicate. Moreover, though on average the listener's brain activity mirrors the speaker's activity with a delay, we also find areas that exhibit predictive anticipatory responses. We connected the extent of neural coupling to a quantitative measure of story comprehension and find that the greater the anticipatory speaker–listener coupling, the greater the understanding. We argue that the observed alignment of production- and comprehension-based processes serves as a mechanism by which brains convey information.

Universities on the Web

Every time I delve into the MIT Open-CourseWare (OCW) site, I am blown away by the variety and quality of the offerings. d'Oliveira et al. describe the OpenCourseWare project in the July 30 issue of Science:

MIT Open-CourseWare (OCW), available at http://ocw.mit.edu, contains the core academic content used in 2000 classes, presenting substantially all the undergraduate and graduate curriculum from MIT's 33 academic departments. A selection of courses, including introductory physics, math, and engineering, contain full video lectures. Partner organizations have created more than 800 translations of OCW courses in five languages. The OCW team has distributed over 200 copies of the entire Web site on hard drives primarily to sub-Saharan Africa, where Internet access is limited. OCW has grown into a global educational resource.

More than 200 universities worldwide have joined MIT in sharing their own educational materials openly, creating a global body of knowledge that spans many cultures and academic levels. More than 13,000 courses from these schools are available through the OpenCourseWare Consortium portal (http://ocwconsortium.org)

In 2007, OCW introduced a companion site, Highlights for High School (http://ocw.mit.edu/highschool), which catalogs more than 2600 resources embedded in the main OCW site that correspond to U.S. Advanced Placement curricula for physics, calculus, and biology. The Highlights site has received more than 1 million visits since launch, and 70% of visitors report being mostly or completely successful at meeting their educational goals in accessing the site.

This fall, OCW will begin to introduce course materials designed specifically for use by independent learners, which will include complete sets of content, increased focus on problem-solving, and additional self-assessment opportunities. Through these and other pilot programs, the OCW team hopes to develop a better understanding of how to increase the benefits for this varied global audience.

Effect of irrelevant events on voters' evaluations

This study by Healy et al. is interesting. If your home team wins a big game, the incumbent in a subsequent election is favored. Also, surprising wins and losses affect approval of presidential performance:

Does information irrelevant to government performance affect voting behavior? If so, how does this help us understand the mechanisms underlying voters’ retrospective assessments of candidates’ performance in office? To precisely test for the effects of irrelevant information, we explore the electoral impact of local college football games just before an election, irrelevant events that government has nothing to do with and for which no government response would be expected. We find that a win in the 10 d before Election Day causes the incumbent to receive an additional 1.61 percentage points of the vote in Senate, gubernatorial, and presidential elections, with the effect being larger for teams with stronger fan support. In addition to conducting placebo tests based on postelection games, we demonstrate these effects by using the betting market's estimate of a team's probability of winning the game before it occurs to isolate the surprise component of game outcomes. We corroborate these aggregate-level results with a survey that we conducted during the 2009 NCAA men's college basketball tournament, where we find that surprising wins and losses affect presidential approval. An experiment embedded within the survey also indicates that personal well-being may influence voting decisions on a subconscious level. We find that making people more aware of the reasons for their current state of mind reduces the effect that irrelevant events have on their opinions. These findings underscore the subtle power of irrelevant events in shaping important real-world decisions and suggest ways in which decision making can be improved.

Being wrong...

I've been meaning to point out a Dwight Garner review on two books on humans making errors, “Being Wrong,” by Kathryn Schulz, and “Wrong,” by David H. Freedman. Daniel Gilbert offers a further review of the Schulz book, which appears to have won uniform praise from many reviewers:

...an insightful and delightful discussion of the errors of our ways — why we make mistakes, why we don’t know we are making them and what we do when recognition dawns. ...Ms. Schulz’s book is a funny and philosophical meditation on why error is mostly a humane, courageous and extremely desirable human trait. She flies high in the intellectual skies, leaving beautiful sunlit contrails. God isn’t her co-pilot; Iris Murdoch seems to be...Mr. Freedman’s book is a somewhat cruder vehicle. It’s a John Stossel-like exposé of the multiple ways that society’s so-called experts (scientists, economists, doctors) let us down, if not outright betray us. It’s a chunk of spicy populist outrage, and it can be a hoot to watch Mr. Freedman’s reading glasses steam up as he, like Big Daddy in “Cat on a Hot Tin Roof,” sniffs mendacity around the plantation.

I tweet, therefore I am...

This piece by Peggy Orenstein in yesterday's New York Times Sunday Magazine gave me an 'a ha' moment as one of its passages made clear to me why, after setting up and starting to do Twitter posts (tweets), I've felt a real inertia about generating tweets as I came across interesting and sometimes self-defining bits of material. In a sense it feels like like I am violating my own privacy, and Orenstein puts it nicely as she notes blurring "the lines not only between public and private but also between the authentic and contrived self. Some clips:

Each Twitter post seemed a tacit referendum on who I am, or at least who I believe myself to be...Each put a different spin on the occasion, of who I was within it...it was about how I imagined — and wanted — others to react to them... How much, I began to wonder, was I shaping my Twitter feed, and how much was Twitter shaping me?

Back in the 1950s, the sociologist Erving Goffman famously argued that all of life is performance: we act out a role in every interaction, adapting it based on the nature of the relationship or context at hand. Twitter has extended that metaphor to include aspects of our experience that used to be considered off-set: eating pizza in bed, reading a book in the tub, thinking a thought anywhere, flossing. Effectively, it makes the greasepaint permanent, blurring the lines not only between public and private but also between the authentic and contrived self. If all the world was once a stage, it has now become a reality TV show: we mere players are not just aware of the camera; we mug for it.

(Funny thing... after writing this post yesterday morning I found myself yesterday afternoon mysteriously starting to send out tweets on articles I was finding interesting.)

(Mis)understanding mirror neurons

This may be a bit technical for many MindBlog readers, but Hickok and Hauser offer a simple, succinct, and incisive critique of the current dogma about mirror neurons that is sufficiently important that I would like to pass it on.  They suggest, as an alternative to the common assumption that mirror neurons are involved in action understanding, that their activity instead might reflect sensory-motor learning. They illustrate this distinction with a simple graphic (in which ventral stream refers to pathways moving more through the temporal lobe of the brain - the 'what' pathway, with dorsal stream routing more through the parietal lobe - the 'where' pathway. Both pathways converge in pre-motor cortical areas such as F5):

Summary
It is hard to imagine a class of neurons that has generated more excitement than mirror neurons, cells discovered by Rizzolatti and colleagues [1] in macaque area F5 that fire both during action execution and action observation. We suggest, however, that the interpretation of mirror neurons as supporting action understanding was a wrong turn at the start, and that a more appropriate interpretation was lying in wait with respect to sensorimotor learning. We make a number of arguments, as follows. Given their previous work, it would have been natural for Rizzolatti's group to interpret mirror neurons as involved in action selection rather than action understanding. They did not make this assumption because, at the time, the data suggested that monkey behavior did not support such an interpretation. Recent evidence shows that monkeys do, in fact, exhibit behaviors that support this alternative interpretation. Thus, the original basis for claiming that mirror neurons mediate action understanding is no longer compelling. There are independent arguments against the action understanding claim and in support of a sensorimotor learning origin for mirror neurons. Therefore, the action understanding theory of mirror neuron function requires serious reconsideration, if not abandonment.
Main Text
Mirror neurons were discovered in the context of research aimed at understanding how the visual properties of objects are integrated with motor codes for action. Cells in area F5 were found to respond to visually presented objects as well as during grasping actions towards those objects. The interpretation of this circuit was that it coded a “vocabulary of motor acts and that this vocabulary can be accessed by … visual stimuli” (p. 491) [2] and that it was critical for “learning associations, including arbitrary associations between stimuli and [motor] schemas” (p. 317) [3]. This is a “‘pragmatic’ mode of processing, the function of which is to extract parameters that are relevant to action, and to generate the corresponding motor commands” (p. 320), as opposed to “‘semantic’ analysis [which is] performed in the temporal lobe” (p.314) [3]. Thus, the meaning of objects is not coded in F5, although clearly, “the semantic system can influence the pragmatic system” (p. 320) [3] (for example, we want to reach for food not snakes).

Mirror neurons were discovered within this same circuit and found to have similar sensorimotor properties [1,4]. It was even suggested that “the actions performed by other monkeys must be a very important factor in determining action selection” (p. 179) [4] and that “the [motor] vocabulary of F5 can be addressed in two ways: by objects and by events [actions]” (p. 317) [3]. Thus, the theoretical and empirical pieces were in place to interpret mirror neurons as sensorimotor association cells relevant to action selection, just like object-oriented cells (Figure 1). But this interpretation was not considered — why?

Figure 1 (click to enlarge)
Schematic models of dorsal and ventral stream function.
(A) The current dominant model [1], which holds that object- and action-oriented processes for sensorimotor integration and ‘understanding’ are organized differentially, with action understanding part of the dorsal sensorimotor stream and object ‘understanding’ part of the ventral stream. (B) A more conventional model in which object- and action-oriented processes for sensory-motor integration and understanding are organized similarly. Both models assume that semantic information from the ventral stream can modulate sensorimotor processes in the dorsal stream.

It was the mirroring property of mirror neurons that steered investigators away from a straightforward sensorimotor interpretation. The logic was, if mirror actions (for example, imitation) are not in the species' repertoire, then mirror neurons can have no motor selection function. Rizzolatti and Craighero used this argument, pitting “two main hypotheses” of mirror neuron function, imitation and action understanding; because macaques do not imitate, they argued, mirror neurons must support action understanding (p. 172) [1]. However, these authors, and the field generally, have failed to notice that other forms of mirror actions are in the macaque motor repertoire. For example, field studies show that rhesus monkeys perceive human gestures as goal-directed, including those that mimic the rhesus monkeys' species-specific signal for coalition recruitment [5]. Macaques also engage in contagious yawning, where perception of another's yawn triggers a yawn in the observer [6]. Further, experimental work has found that another's grasping actions toward one of two food receptacles serves as a cue to goal-directed grasping toward that same receptacle [7] — an experimental situation reminiscent of the mirror neuron studies. Even domesticated dogs mirror goal-directed actions of a model dog [8]; one would expect to find mirror neurons in dogs given this behavioral evidence. And lastly, rhesus monkeys comprehend actions that they are physically incapable of producing. In particular, though rhesus monkeys do not throw, they can recognize a throwing action in humans, realizing that throwing a rock is dangerous whereas throwing food is not [5].

Observed actions can serve as important inputs to action selection, including, but not necessarily limited to, mirror actions. Therefore, the motivating argument for the action understanding theory over a sensorimotor theory (for example [9]) does not hold.

Can we distinguish the sensorimotor and action understanding theories of mirror neurons? Yes: empirical findings favor the sensorimotor account by showing that action understanding and motor system function dissociate [10], that motor actions alone are insufficient to explain action understanding [5], that animals comprehend many actions that they cannot execute [10], and that sensorimotor learning can transform the mirror system [9].

In summary, a sensorimotor theory can explain the response properties of mirror neurons, does so more straightforwardly, and does not suffer the empirical roadblocks of the action understanding theory [5,10]. It is time to reconsider mirror neuron function and the neural basis of action understanding.

References
1 Rizzolatti, G., and Craighero, L. (2004). The mirror-neuron system. Annu. Rev. Neurosci. 27, 169–192.
2 Rizzolatti, G., Camarda, R., Fogassi, L., Gentilucci, M., Luppino, G., and Matelli, M. (1988). Functional organization of inferior area 6 in the macaque monkey. II. Area F5 and the control of distal movements. Exp. Brain Res. 71, 491–507.
3 Jeannerod, M., Arbib, M.A., Rizzolatti, G., and Sakata, H. (1995). Grasping objects: the cortical mechanisms of visuomotor transformation. Trends Neurosci. 18, 314–320.
4 di Pellegrino, G., Fadiga, L., Fogassi, L., Gallese, V., and Rizzolatti, G. (1992). Understanding motor events: a neurophysiological study. Exp. Brain Res. 91, 176–180.
5 Hauser, M., and Wood, J. (2010). Evolving the capacity to understand actions, intentions, and goals. Annu. Rev. Psychol 61, 303–324, C301.
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Resilience in the face of adversity - brain correlates

Interesting work from Dolan's group on how we modulate expected aversive outcomes:

The value assigned to aversive events is susceptible to contextual influences. Here, we asked whether a change in the valuation of negative events is reflected in an altered neuronal representation of their expected aversive outcome. We show that experiencing an aversive event in the past, and choosing to experience it in the future, reduces its aversive value. This psychological change is mirrored in an altered neural representation of aversive value in the caudate nucleus and anterior cingulate cortex. Our findings indicate that subcortical regions known to track expected value such as the caudate nucleus, together with anterior cingulate cortical regions implicated in emotional modulation, mediate a revaluation in expectancies of aversive states. The results provide a striking example of a contextual sensitivity in how the brain ascribes value to events, in a manner that may foster resilience in the face of adversity.

Reciprocity engages our brain's reward system.

Interesting stuff from Phan et al:

Brain reward circuitry, including ventral striatum and orbitofrontal cortex, has been independently implicated in preferences for fair and cooperative outcomes as well as learning of reputations. Using functional MRI (fMRI) and a “trust game” task involving iterative exchanges with fictive partners who acquire different reputations for reciprocity, we measured brain responses in 36 healthy adults when positive actions (entrust investment to partners) yield positive returns (reciprocity) and how these brain responses are modulated by partner reputation for repayment. Here we show that positive reciprocity robustly engages the ventral striatum and orbitofrontal cortex. Moreover, this signal of reciprocity in the ventral striatum appears selectively in response to partners who have consistently returned the investment (e.g., a reputation for reciprocity) and is absent for partners who lack a reputation for reciprocity. These findings elucidate a fundamental brain mechanism, via reward-related neural substrates, by which human cooperative relationships are initiated and sustained.

Twitter-mood

Here is a cute study that attempts to gauge  our mood (more accurately, the 7% of American who use Twitter) throughout the day.  Play through the video that shows regional and time of day differences.  From the quickie NYTimes mention of the work: "you’re probably happiest in the morning and least satisfied about noon. Analyzing words in those posts, researchers found that Thursday is the saddest day; Sunday, the happiest. People on the West Coast who post are happier than their counterparts on the East Coast. The moods were mapped, showing happy times (greener areas) and unhappy (red areas)."

Altruism as good business - shoppers who care

Gneezy et al. add an interesting twist to studies of how we buy things. Companies loose money in attempts to enhance sales with pay-what-you-want pricing, and adding a charitable contribution to standard pricing has little effect. However, in a variation of pay-what-you-want with half going to charity, a more reasonable profit was returned. (It is not clear whether the charitable giving by the company generated additional generosity by the consumer or created additional social pressure.)

A field experiment (N = 113,047 participants) manipulated two factors in the sale of souvenir photos. First, some customers saw a traditional fixed price, whereas others could pay what they wanted (including $0). Second, approximately half of the customers saw a variation in which half of the revenue went to charity. At a standard fixed price, the charitable component only slightly increased demand, as similar studies have also found. However, when participants could pay what they wanted, the same charitable component created a treatment that was substantially more profitable. Switching from corporate social responsibility to what we term shared social responsibility works in part because customized contributions allow customers to directly express social welfare concerns through the purchasing of material goods.