The Mellow Years?: Neural Basis of Improving Emotional Stability over Age

Several studies have documented that older adults show a shift in the ratio of positive-to-negative emotion, with a reduction in the experience, memory, and recognition of negative emotion, but an increase for positive emotion. A recent article by Williams et al with the title of this post shows some of what is going on in in the brains of these older adults. They used fMRI (function Magnetic Resonance Imaging) or ERP (Event related potentials recorded on the surface of the scalp) to examine the activity of the medial prefrontal cortex (MPFC) that is central in inhibiting or enhancing emotional functions. Subject also rated their own reactions to photographs shown during the measurements of fearful, happy, or neural faces. A shift in responses to positive versus negative emotion over age was seen in both recognition and brain function. Recognition of negative emotion (fear, shown in red in right part of figure) showed a significant decline as a function of increasing age, whereas
recognition for positive emotion (happiness) increased.


Credit: J. Neuroscience

Changes in both ERP (over the time course 40–450 ms after stimulus) and fMRI measures over age. Happiness relative to neutral showed a decrease in activity over the medial prefrontal region (shown in blue), which was most apparent for neural activity elicited during the early phase of processing (40–150 ms after stimulus). In response to fear, in contrast, there was an increase in activity over the medial prefrontal cortex with age (shown in red), which ERPs showed was most apparent for neural activity occurring in the later phase of the time course (180–450 ms after stimulus).

Fear elicited corresponding increases in medial prefrontal activation, apparent during the later (180–450 ms) controlled phase of processing. In contrast, medial prefrontal activation to happiness attenuated over age, apparent in the early, automatic (within 150 ms) phase of the time course. These changes indicate that processing resources are shifted from the automatic phase of stimulus appraisal toward a greater allocation during the controlled phase of stimulus evaluation. The authors propose that this shift in resources supports better selective control of reactions to negative, particularly threat-related stimulation and allows positive responses to proceed without restraint. Their observation that this shift in processing of negative versus positive emotion predicted better emotional wellbeing with older age supports the view that it contributes to an increasingly adaptive regulation of emotion.

The authors propose that life experience and changing motivational goals may drive plasticity in the medial prefrontal brain systems to increase selective control over the balance of negative and positive emotion, with the consequence of improving emotional wellbeing.

"The motivation to achieve better emotional control in older adults may come from the increasing awareness of one’s mortality and the desire to maximize the meaningfulness of environmental events and input, over and above the need for acquisition. With repeated emotional experiences over the lifespan, humans may learn to be more selective about which input is likely to provide quality positive outcomes as opposed to cause distress. Consistent with this view, older adults are more selective about their social activities and tend to prioritize quality rather than quantity."

The mysteries of blog-land, Feedburner and Linkie Winkie

Having just put a feed for feed readers on this blog, I find myself totally out of my depth and would be most grateful if a techie happens to read this post and could enlighten me on what is going on. One of the icons at the lower right hand of this blog page directs you to FeedBurner, which offer to put the feed from this site onto MyYahoo, MyAol, MyGoogle or whatever feedreader you might be using. The guy helping me also put RSS and other icons on the page that let you place the feed directly on those readers without going through FeedBurner. Feedburner reports back that since I connected with it 5 days ago an average of 3 sites have subscribed to this blog's feed each day. One site, the Linkie Winkie web crawler, appears to sign up each day? It has minimum content, but a few links indicate that guys involved with SEO (search engine optimization) set it up as an altruistic gesture.....

I hope someone out there might explain this to me....

Oxytocin, Affiliative Neuroscience, make the NYTimes Op-Ed page!

The conservative columnist David Brooks has a Sunday Times (July 2) piece titled "Of Human Bonding," He suggests that some of Mr. Buffet's billions given to the Gates foundation could well be spent on research on affiliative neuroscience and hormones like oxytocin that promote bonding and nurturing behavior (see my Feb. 13 posting on oxytocin). Brooks notes that "Attachment theory has been thriving for decades, but it's had little impact on public policy. That's because the policy world is a supermagnet for people who are emotionally avoidant. If you go to a Congressional hearing and talk demography, you are treated like a serious policy wonk, but if you start talking about relationships, people look at you as if you're Oprah." ...."everything we're learning about the brain confirms the centrality of attachments to human development and the wisdom of Adam Smith's observation that the "chief part of human happiness arises from the consciousness of being beloved." (Brain research rarely reveals anything new about human nature; it just tells you which of the old verities are most important.)" Brooks points out that billions of dollars have been spent trying to improve math in reading scores in high schools, without engaging the core issue: the emotional disengagement caused by lack of caring and attachment.

Genes that regulate risk taking, addiction, obesity, sexual desire and orientation....

It is hard to ignore increasing evidence that significant personality variations can be inherited. We are not (to use the title of Steven Pinker's 2002 book) "blank slates."

An article by Amy Harmon in the June 15 N.Y.Times provides a nice table summary of a few of the genes known to influence behavior in humans and other animals:

INSIG2 - Obesity - A common gene variant that is associated with significantly increased risk of becoming fat among the more than 25 million Americans who carry it. Herbert et al. (2006) "A Common Genetic Variant Associated with Adult and Childhood Obesity". Science 312:279-283.

neuroD2 - Risk-taking - Mice lacking neuroD2 have a greatly reduced sense of fear. Variants of the human version of this gene may lead to risk-taking behaviors. Lin et al. "The dosage of neuroD2 transcription factor regulates amygdala development and emotional learning" Proceedings of the National Academy of Science 41:14877-14882

CYP2A6 - Nicotine Addiction - People with certain forms of this gene smoke more and are more likely to become addicted to cigarettes. Tailoring treatments based on which form of CYP2A6 a person has may help him or her quit. Minematsu et al. (2006) "Limitation of cigarette consumption by CYP2A6*4, *7 and *9 polymorphisms" European Respiratory Journal 27:289-292. Malaiyandi et al. (2006) "Impact of CYP2A6 genotype on pretreatment smoking behavioral and nicotine levels and usage of nicotine replacement therapy". Molecular Psychiatry (2006): 400–409.

AVPR1a and SLC6A4 - Dance talent - Variants of these genes are correlated with creative dance performance. Bachner-Melman et al. "AVPR1a and SLC6A4 Gene Polymorphisms Are Associated with Creative Dance Performance". PLoS Genetics 1(3): e42

DRD2 - Anorexia - Variants of this receptor for the neurotransmitter dopamine have been preliminarily linked to the risk of developing anorexia. Bergen et al. (2005) "Association of Multiple DRD2 Polymorphisms with Anorexia Nervosa" Neuropsychopharmacology 30, 1703-1710.

DRD4 - Sexual desire - Another dopamine receptor gene that is linked in this study with sexual desire and performance. Zion et al. (2006) "Polymorphisms in the dopamine D4 receptor gene (DRD4) contribute to individual differences in human sexual behavior: desire, arousal and sexual function". Molecular Psychiatry (published online ahead of print)

fruitless - Sexual orientation - Male and female fruit flies make different forms of this gene. Males carrying the female gene do not court females. Females carrying the male gene are attracted to other females. Demir and Dickson (2005). "fruitless Splicing Specifies Male Courtship Behavior in Drosophila" Cell 121:785-794.

Several Websites for Cognitive Neuroscience and Brain Information.

You might enjoy checking out The Neuroscience Gateway sponsored by the Allen Institute for Brain Science and Nature Magazine.

Also the Brain Connection aimed more at general public.

And, Brain explorer.

A site with many personal psychology and personality tests that you can take.

Links to a number of cognitive neuroscience sites.

Recent news in cognitive neuroscience.

Cognitive Biases

Check out this wikipedia link. It has a thorough list of errors we make in judgement and thinking.

Prospection

I’m showing you my reduction of Daniel Gilbert’s 238 pages of “Stumbling on Happiness” to about 8 pages of paraphrase and quotation, presented as a series of posts with the main title headings of the book.

The Reduced “Stumbling on Happiness” I. Prospection – looking forward in time.

Ch. 1 Journey to Elsewhen

All brains (squids, squirrels, chimps, humans) make predictions about immediate, local, personal, future based on previous conditioning. This does not require conscious thoughts, and might best be called ‘nexting’ reserving the term predicting for the thoughtful reflection about the future that we do.

The concept of ‘later’ seems unique to humans. Young children don’t have it and must develop it. It is associated with enlarged frontal lobes of cortex. Damage to frontal lobes (cf. the famous case of Phineas Gage) can cause inability to plan and leave one living in a ‘permanent present.’

Why are about 12% of the average person’s daily thoughts about the future?

Prospection can provide pleasure and prevent pain. Thinking about the future can be pleasurable. Anticipating unpleasant events can minimize their impact, motivate us to avoid them.

Prospection can assist control of future events, and we find it gratifying to exercise control, just for the exercise itself.

Subjectivity

The Reduced “Stumbling on Happiness” II. Subjectivity (ch. 2, 3) - the science of happiness, what does the word mean, can we ever measure it.

Chapter 2 – The View from in Here

What are we talking about, making claims about happiness: emotional, moral, and judgmental happiness distinguished.

Emotional happiness a feeling, ‘you know what I mean’ subjective state. But because humans are reluctant to value bovine contentment, they can add ‘happy because’ (as a reward for virtue, for example.. judgmental happiness). However virtue refers to actions, happiness to feelings. Or, they can add ‘happy about’ which is an indication of a stance (how my life is going, whatever) not of feelings.

So, if we reserve the word happiness to subjective emotional experiences described as enjoyable or pleasurable (not morality of actions or judgements of experiences) how do we compare different ‘happy’ experiences and rate or rank them? Gilbert describes a number of demonstrations that our ability to remember or perceive differences in happiness is flawed. Also, all claims of happiness are from someone’s point of view, different people have different ranges of happiness on an intensity of feeling scale.

Chapter 3- Outside Looking In. “How am I feeling” - our answer to that question can be flawed, because our answer is what we are aware of feeling, and our experience can encompass much more than that. Our awareness is usually focused on a small fraction of the total information that our brains are processing (are you paying attention to the feeling in your left elbow right now?). Experience refers to the sense of being engaged while awareness gives us the sense of being cognizant of that engagement. Awareness is a kind of experience of our own experience. Our visual experience and our awareness of that experience are generated by different parts of our brains. Certain kinds of damage (to primary visual cortex) can cause blindsight, where there is no awareness of seeing, yet awareness is present because ‘guesses’ made about visual stimuli presented to the area of blindsight are correct.

Analogous to this some people show decoupling of awareness and emotional experience.. it can be possible for some people to be happy or sad without knowing it.

So, how do we measure it? Is there a ‘happyometer’? No. We have to rely on flawed measures of subjective experience verbally reported. (not measurements of muscle or brain activity). And, have to use statistics, gather and average the reports of large numbers of individuals. If hundreds of people report different degrees of pleasure in eating coconut versus banana cream pie, we could conclude that different pies really do cause different experiences.

Realism

The Reduced “Stumbling on Happiness” Part III. Realism (ch 4,5) – a first short coming of imagination is that it works so quickly, quietly, and effectively that we are insufficiently skeptical of its products.

Chapter 4 In the Blind Spot of the Mind’s Eye.

Our retinas have a ‘blind spot’ with no light sensitive cells, where axons gather to head towards the brain. We don’t walk around with a hole in our visual field because our brains fill in the missing part. Our brains create a similar illusion with memory, the act of remembering involves ‘filling in’ details that we were not actually stored. Everything we take to be ‘real’ in the outside world is actually mostly a fabrication, or interpretation. A small number of actual cues from the environment are combined with our preexisting knowledge to construct our reality.

Chapter 5 The Hound of Silence

The details our brains put in (Ch. 4) are not nearly as troubling as the details it leaves out. We are sensitive to the presence of events, but not to their absence. We note co-occurrence (such as presence of overhead pigeons with being hit by pigeon poop) but not co-absences (not being hit by poop in presence of pigeons), leading us to give false weight to a correlation. We treat the details of future events that we do imagine as thought they were actually going to happen, but we treat the details we don’t imagine as though they were not going to happen. We fail to consider how much imagination fills in, and also how much it leaves out. We imagine the near and far futures with such different textures and intensity that we value them differently as well.

“Any brain that does the filling-in trick is bound to do the leaving-out trick as well, and thus the futures we imagine contain some details that our brains invented and lack some details that our brains ignored..... the problem is that they do this so well we aren’t aware it is happening.”

Presentism

The Reduced “Stumbling on Happiness” IV. Presentism (The tendency for current experience to influence one’s view of the past and the future.) – the second shortcoming of imagination

Chapter 6 The Future Is Now

“Memory uses the filling-in trick, but imagination is the filling in trick, and if the present lightly colors our remembered pasts, it thoroughly infuses our imagined futures.”

The brain images by enlisting the aid of its sensory areas, we imagine an object by recalling memories of similar objects. Just as we preview objects, so we prefeel events. That is, we imagine future emotions on the basis of recalling and recreating similar emotions from our past. We can almost always tell whether a visual experience is the product of a real or an imagined object. But not so with emotional experience. We mix feeling (from current event in the world) with prefeelings (that originate in memory). A ‘reality first’ principle operates. So, if we are asked to imagine how hungry we will feel tomorrow, our answer depends on how full we feel right now. We cannot feel good about an imaginary future when we are busy feeling bad about an actual present. And, we can mistakenly assume that the future event is the cause of the unhappiness we feel in the present when we think about it.

Chapter 7 Time Bombs

Time is an abstraction, not an object, so is compared to space by people all over the world, yet in different ways. Past is ‘behind’ us, future is ‘in front’... English put past on the left, Arabic speakers put past on the right, Mandarin speakers put past on the bottom. Reasoning by metaphors like this can mislead as well as illuminate.

Habituation, adaptation, declining marginal utility, marriage: wonderful things become less wonderful with repetition. Time and variety are two ways to avoid habituation, and if you have one, then you don’t need the other... when episodes are sufficiently separated in time, variety is not only unnecessary, it can be costly. If we compare a variety of dishes we derive different pleasure from, we should want a variety to choose from at a single sitting. If we are asked to choose ahead which we would like at weekly intervals, we pick variety again, but in fact would derive more pleasure from just choosing our favorite dish each week.

What about comparing things in the present, past, and future? If we want to predict how something will make us feel in the future, we must consider the kind of comparison we well be making in the future and not the kind of comparison we happen to be making in the present. Presentism, the temptation to view the past and the future through the lens of the present, is nothing short of overwhelming.

Rationalization

The Reduced “Stumbling on Happiness” V. Rationalization (act of causing something to be or to seem reasonable) – the third shortcoming of imagination.

Ch. 8 Paradise Glossed

Because experiences are inherently ambiguous, finding a “positive view” of an experience is often as simple as finding the ‘below you view’ of a Necker cube. Consumers evaluate kitchen appliances more positively after they buy them, job seekers evaluate jobs more positively after they accept them, etc.. We cook the facts.

"Our experience of the world is a mixture of stark reality and comforting illusion. We can't spare either. If we were to experience the world exactly as it is, we'd be too depressed to get out of bed in the morning, but if we were to experience the world exactly as we want it to be, we'd be too deluded to find our slippers...we might think of people as having a psychological immune system that defends the mind against unhappiness in much the same way that the physical immune system defends the body against illness. This metaphor is unusually appropriate. For example, the physical immune system must strike a balance between two competing needs: the need to recognize and destroy foreign invaders such as viruses and bacteria, and the need to recognize and respect the body's own cells. If the physical immune system is hypoactive, it fails to defend the body against micropredators and we are stricken with infections; but if the physical immune system is hyperactive, it mistakenly defends the body against itself and we are stricken with autoimmune disease.... A healthy physical immune system must balance its competing needs and find a way to defend us well - but not too well...."

"Analogously, when we face the pain of rejection, loss, misfortune, and failure, the psychological immune system must not defend us too well ("I'm perfect and everyone is against me") and must not fail to defend us well enough ("I'm a loser and I ought to be dead"). A healthy psychological immune system strikes a balance that allows us to feel good enough to cope with our situation but bad enough to do something about it ("Yeah, that was a lousy performance and I feel crummy about it, but I've got enough confidence to give it a second shot."). We need to be defended, not defenseless or defensive, and thus our minds naturally look for the best view of things while simultaneously insisting that those views stick reasonably closely to the facts."

At the chapter end, after a further section on how we conspire to see mostly what we want to see; "To ensure that our views are positive, our eye looks for what our brain wants. The conspiracy between these two servants allows us to live at the fulcrum of stark reality and comforting illusion."

Chapter 9 Immune to Reality

Research suggests that people are typically unaware of the reasons why they are doing what they are doing, but when asked for a reason, they readily supply one. Words like ‘hostile’, ‘elderly’, ‘stupid’ when flashed for only milliseconds on a screen are not perceived, but influence subsequent behavior. The downstairs saw them, but our upstairs did not. For positive views to be credible, they must be based on facts that we believe we have come upon honestly. We accomplish this by unconsciously cooking the facts and then consciously consuming them. The diner is in the dining room, but the chef is in the basement.

Our psychological immune system can put a positive spin on almost any negative experience. This is easier to do with actions one takes than with inactions. People seem to regret not having done things more than doing them.

Our defensive system can cook facts and shift blame in response to major assaults (lost jobs, failed marriages) but is less likely to do this with small challenges (subtle insults, late elevators, late appointments). Intense suffering triggers the very processes that eradicate it, while mild suffering does not, and this counterintuitive fact can make it difficult for us to predict our emotional futures.

We are more likely to look for and find a positive view of the things we’re stuck with than of the things we’re not. (not excusing behavior in a friend that we excuse in a sibling or spouse.) Apparently, inescapable circumstances trigger the psychological defenses that enable us to achieve positive views of those circumstances, but we do not anticipate that this will happen.

Explanations (real or apparent, even if irrelevant or incorrect) can rob events of their emotional impact, because it makes them seem likely and allows us to quit thinking about them.

Onward (end of chapter summary):
“The eye and the brain are conspirators, and like most conspiracies, theirs is negotiated behind closed doors, in the back room, outside of our awareness. Because we do not realize that we have generated a positive view of our current experience, we do not realize that we will do so again in the future. Not only does our naiveté cause us to overestimate the intensity and duration of our distress in the face of future adversity, it also leads us to take actions that may undermine the conspiracy. We are more likely to generate a positive and credible view of an action than an inaction, of a painful experience than of any annoying experience, of an unpleasant situation that we cannot escape than of one we can. And yet, we rarely choose action over inaction, pain over annoyance, and commitment over freedom.”

“Our tour of imagination has covered a lot of ground – from realism (part III) to presentism (part IV) to rationalization (part V) – so before moving on to our final destination, it may be useful to locate ourselves on the big map. We’ve seen how difficult it is to predict accurately our emotional reactions to future events because it is difficult to imagine them as they will happen, and difficult to imagine how we’ll think about them once they do. Throughout this book, I’ve compared imagination to perception and memory, and I’ve tried to convince you that foresight is just as fallible as eyesight and hindsight....... can we remedy the problems of foresight? .....we can. But we generally choose not to.

Corrigibility

The Reduced “Stumbling on Happiness” VI. Corrigibility (capability of being corrected, reformed, or improved.)

Chapter 10 Once Bitten

Why don’t we learn from our direct experience or that of others how better to predict the future? Because we tend to remember the best of times and the worst of times instead of the most likely of times. Memory stores an idiosyncratic synopsis of our experience, and emphasizes final scenes, or final items in a series of events. Experiments show that the way an experience ends is more important to us than the total amount of pleasure we receive – until we think about it. After an important event (such as the Gore/Bush election) we remember feeling as we had expected to feel (highly elated or crushed), not as we actually felt (slightly elated or crushed). Prospections and retrospections can be in perfect agreement despite the fact that neither accurately describes our actual experience.

Chapter 11 Reporting live from tomorrow

Like genes, some beliefs are transmitted more successfully than others. Inaccurate beliefs can prevail in the belief-transmission game if they somehow facilitate their own “means of transmission.” False beliefs that happen to promote stable societies tend to propagate because people who hold these beliefs tend to live in stable societies, which provide the means by which false beliefs propagate....some of our cultural wisdom about happiness looks suspiciously like a super-replicating false belief.

Consider money. A bedrock of our economic behavior is the assumption that people are better off if they end up with more money rather than less. This is true for the amount of money needed to lift people out of poverty and into the middle class, but beyond that money does little to increase happiness. If food and money both stop pleasing us once we’ve had enough of them, why do we continue to stuff our pockets when we would not continue to stuff our faces? Market economies require that we all have an insatiable hunger for stuff, if everyone were content with the stuff they had, then the economy would grind to a halt... the fundamental needs of a vibrant economy and the fundamental needs of a happy individual are not necessarily the same... economies can blossom and grow only if people are deluded into believing that the production of wealth will make them happy. ...the propagation of false beliefs does not require that anyone be “trying” to perpetrate a magnificent fraud on an innocent populace. There is no cabal at the top, no start chamber, no master manipulator whose clever program of indoctrination and propaganda has duped us all into believing that money can buy us love. Rather, this particular false belief is a super-replicator because holding it causes us to engage in the very activities that perpetuate it. ... we are nodes in a social network that arises and falls by a logic of its own, which is why we continue to toil, continue to mate, and continue to be surprised when we do not experience all the joy we so gullibly anticipated.

There IS a simple method by which anyone can make strikingly accurate predictions about how they will feel in the future. ....by and large no one wants to use it. We can give up on remembering and imagining entirely and use other people as surrogates for our future selves. There is someone out there who is now experiencing the future event that we are merely thinking about, and for the most part they are more than willing to tell us about it.
But, you say, “I’m special, it won’t help me to know other people’s experiences as proxies for my own... I’m better off basing my predictions on my own imagination than on reports of people who are so different from me.”

Imagination (see above) has the shortcomings of filling in and leaving out without telling us (section on realism), of projecting the present onto the future (presentism), of failing to recognize that things will look different once they happen (rationalization). Can surrogation remedy these shortcomings? Several studies show that when people are forced to use others as surrogates, and are deprived of the information that imagination requires, they make remarkably accurate predictions about their future feelings, which suggests that the best way to predict our feelings tomorrow is to see how others are feeling today.

We think we will do better with information about a prize, food choices, etc than with information about how a randomly selected individual felt after winning them or eating them. This is because most people don’t know they are like most other people. One of the most reliable facts about the average person is that the average person doesn’t see herself as average. Ninety percent of motorists consider themselves to be safer-than average driver, 94 percent of college professors consider themselves to be better than average teachers, etc. Many studies show that “Most of us appear to believe that we are more athletic, intelligent, organized, ethical, logical, interesting, fair-minded, and healthy – not to mention more attractive – than the average person.” We don’t always see ourselves as superior, but we almost always see ourselves as unique.

Our mythical belief in the variability and uniqueness of individuals is the main reason why we refuse to use others as surrogates.

...the information we need to make accurate predictions of our emotional futures is right under our noses... It doesn’t always make sense to heed what people tell us when they communicate their beliefs about happiness, but it does make sense to observe how happy they are in different circumstances.

Final sentence of book:
“There is no simple formula for finding happiness. But if our great big brains do not allow us to go sure-footedly into our futures, they at least allow us to understand what makes us stumble.”

In another culture, the future is behind you.

Time is an abstraction, not an object, so is compared to space by people all over the world, yet in different ways. Past is ‘behind’ us, future is ‘in front’... English put past on the left, Arabic speakers put past on the right, Mandarin speakers put past on the bottom. Reasoning by metaphors like this can mislead as well as illuminate.

James Gorman, in the Tuesday June 27 N.Y. Times, now notes a fascinating article by Núñez and Sweetser: With the Future Behind Them: Convergent Evidence From Aymara Language and Gesture in the Crosslinguistic Comparison of Spatial Construals of Time, Cognitive Science 30 (2006) 401–450.

Now it appears that speakers of the Indian language of the high Andes, Aymara, see the future as behind them and the past as ahead of them. They gesture ahead of themselves when remembering things past, and backward when talking about the future. Aymara speakers see the difference between what is known and not known as paramount, and what is known is what you see in front of you, with your own eyes. The past is known, so it lies ahead of you. The future is unknown, so it lies behind you, where you can't see. Gorman wonders "Is it possible that human concepts of time can vary this much because of language and culture? And what would it be like to think this way? Do I have the rest of my life behind me? And how can I let bygones be bygones if they're right in front of me?"

Our perception of gender from biological movement: It's adaptation suggests brain neurons selective for this task.

You have probably had the experience of sitting in a railway car and watching a train slowly moving past you for a period. After it has passed the stationary platform opposite you seems to be moving in the opposite direction. This is an example of motion adaptation that reflects changes in simple feature detecting neurons very early in our visual pathway. What about a higher order feature like gender discrimination from body movement? We can readily identify the gender of a human walk, even when the only visible information comes from lights attached to the major joints: Female (left), Neutral (middle), and Male (right) of the body (the point light walker, PLWer). Jordan et al have shown that viewing a female PLWer for a period of time increases the probability of viewing a subsequent ambiguous PLWer as male, and vice versa. As no single light alone conveys sufficient information, this gender discrimination requires the integration of local information into a global percept. Because prolonged viewing of PLWers is found to produce systematic shifts in gender discrimination of subsequent ambiguous stimuli, this provides evidence of gender-specific adaptation that cannot be accounted for by adaptation of constitutive lower-order features like those in motion adaptation. Rather, it suggests the existence of neurons or groups of neurons selective for gender, as derived from biological motion. These neurons might be in cortical areas previously identified as gender-related.

Angry Faces. Men detect them better than women do.

Williams and Mattingley have done an elegant study (Current Biology, vol. 16, pp 402-404, June 2006) that demonstrates that men detect angry male faces significantly more rapidly than women do. On the other hand, women are faster a picking out a happy, sad, surprised or disgusted face. The addition of neutral distractor faces to the search display has little effect on the detection of angry male faces by either male or female observers.

A brief quote from the beginning of their article give the context and importance of their observations: "In humans, evolution has resulted in marked differentiation between males and females, including differences in the structural and functional organization of the brain. These differences are reflected in patterns of cognitive and behavioural abilities. For example, females tend to perform better than males at fine motor and perceptual discrimination tasks, whereas males are better at route-finding tasks. Males are also physically larger and more aggressive than females, and so more likely to pose a physical threat. Such physical differences between the sexes may in turn have shaped the cognitive processes involved in detecting threatening behaviour in others. Early detection of an angry facial expression, for example, might reduce the likelihood of an injurious or potentially fatal confrontation. Similarly, detection of a fearful expression might warn of a potential threat in the immediate vicinity. Although much emphasis has been placed on such cognitive and physical distinctions between the sexes, few studies have investigated differences in the efficiency with which males and females perceive facial expressions, despite the potential importance of affect perception for survival......From an evolutionary perspective, the potential for physical threat from a male is greater than that from a female. A perceptual system that prioritizes detection of angry male faces, which directly signal potential threat, is therefore likely to be advantageous."

Neuromarketing: a growing menace?

Check out this article by Mary Carmichael describing how marketers are teaming up with cognitive scientists doing MRI to find the advertising stimuli most likely to stimulate the appetitive and reward centers in the brain.

Decreasing chronic pain by learning how to decrease activity in the brain areas regulating it.

The truncated abstract from the article by deCharms et al. in PNAS follows:

"If an individual can learn to directly control activation of localized regions within the brain, ...this... could potentially provide a different route for treating disease. ... Here, we found that by using real-time functional MRI (rtfMRI) to guide training, subjects were able to learn to control activation in the rostral anterior cingulate cortex (rACC), a region putatively involved in pain perception and regulation. When subjects deliberately induced increases or decreases in rACC fMRI activation, there was a corresponding change in the perception of pain caused by an applied noxious thermal stimulus. ..... Chronic pain patients were also trained to control activation in rACC and reported decreases in the ongoing level of chronic pain after training. "

See also "Believe in Your Placebo" which reviews experiments showing how rACC and other brain areas are altered during the placebo effect.

Changes in genes and fearful behavior caused by early life stress can be reversed.

The information in our genes can be permanently altered by 'epigenetic' modifications, such as adding methyl groups to DNA. Infant rats that receive abundant licking and grooming from their mothers in their first week of life show increased methylation of their glucocorticoid receptor (GR) genes, and increased production of the GR in several tissues involved in the hypothalamic-pituitary-adrenal (HPA) response to stress. Infants that do not receive as much care show decreased methylation and are more fearful as adults under conditions of stress. Weaver et al. centrally infused the brains of these more fearful adults with the essential amino acid L-methionine, a precursor to S-adenosyl-methionine that serves as the donor of methyl groups for DNA methylation. They found that methionine infusion reversed the effect of maternal behavior on DNA methylation, GR expression, and hypothalamic-pituitary-adrenal and behavioral responses to stress, suggesting a causal relationship among epigenomic state, GR expression, and stress responses in the adult offspring. Their results demonstrate that, despite the inherent stability of the epigenomic marks established early in life through behavioral programming, they are potentially reversible in the adult brain.

Your Amazing Brain

This site is fun, check it out... Your Amazing Brain. There are a number of clever quick time exercises on aspects of how our brains work (memory, love and sex, brain injury, etc.), Try the "test yourself" section, especially the exercises on body language and reading faces.

Emotional Communication in Humans and other Primates.

This is the title of a review by Parr et al. (Current Opinion in Neurobiology, vol. 15, pp 716-720, Dec. 2005), whose abstract I include here, with a main point of this post being to show pictures of the similar facial muscle groups used by humans and chimpanzees in emotional communication.


Credit: Current Opinions in Neurobiology.

"The social brain hypothesis proposes that large neocortex size in Homonoids evolved to cope with the increasing demands of complex group living and greater numbers of interindividual relationships. Group living requires that individuals communicate effectively about environmental and internal events. Recent data have highlighted the complexity of chimpanzee communication, including graded facial expressions and referential vocalizations. Among Hominoids, elaborate facial communication is accompanied by specializations in brain areas controlling facial movement. Finally, the evolution of empathy, or emotional awareness, might have a neural basis in specialized cells in the neocortex, that is, spindle cells that have been associated with self-conscious emotions, and mirror neurons that have recently been shown to activate in response to communicative facial gestures."