A memory activates the same brain cells as the original experience.

A fascinating observation from Gelbard-Sagiv et al., who studied patients with pharmacologically intractable epilepsy with implanted depth electrodes to localize the focus of seizure onset. Benedict Carey discusses the work. Here is the original abstract:

The emergence of memory, a trace of things past, into human consciousness is one of the greatest mysteries of the human mind. Whereas the neuronal basis of recognition memory can be probed experimentally in human and nonhuman primates, the study of free recall requires that the mind declare the occurrence of a recalled memory (an event intrinsic to the organism and invisible to an observer). Here, we report the activity of single neurons in the human hippocampus and surrounding areas when subjects first view television episodes consisting of audiovisual sequences and again later when they freely recall these episodes. A subset of these neurons exhibited selective firing, which often persisted throughout and following specific episodes for as long as 12 seconds. Verbal reports of memories of these specific episodes at the time of free recall were preceded by selective reactivation of the same hippocampal and entorhinal cortex neurons. We suggest that this reactivation is an internally generated neuronal correlate of the subjective experience of spontaneous emergence of human recollection.

The teenage brain.

Harvard Magazine has an interesting brief article describing work on the teenage brain being done at Harvard Medical School.

Online brain and cognitive science courses

Every week or so I get an email from a reader asking "how do I find out more about......" or "what is a good book on...." Apart from specific information that I can pass on, I should mention here what I suggest to them (in addition to a google search using proper search terms): The MIT open course ware, for example in Brain and Cognitive science, is amazing. There are a total of 1800 offerings in all college areas.

A taste test for depression?

From a report by Cahoon on the July Physiological Society Meetings in Cambridge, UK.

Melichar and Donaldson gave healthy volunteers a tiny dab of faint flavor on the tongue and asked if they could taste it. The sample was so diluted that they couldn't. The researchers then gave the volunteers pills that boosted brain levels of one of two neurotransmitters, serotonin or noradrenaline. To boost serotonin, for example, patients took a Prozac-like drug known as a selective serotonin-reuptake inhibitor. When volunteers got a serotonin jump, they were suddenly able to taste the feeble flavor if it was bitter or sweet. With noradrenaline boosted, the volunteers were able to taste the dab if it was bitter or sour. Donaldson and Melichar suspected that depressed people had blunted taste buds--the illness is often tied to a lack of either neurotransmitter--and that the right antidepressant would allow depressed people to experience the true vibrancy of flavors.

Experiments are being planned to determine the validity of a taste test for depression:

If those results validate the flavor test, it could become the equivalent of the cholesterol test that persuades someone to take action against heart disease. "The patient has no objective marker" that tells them they're depressed, says Melichar. As a result, he notes, a lot of people end up not taking their medication.

Moreover, given that the researchers have found that serotonin is linked to sweet and noradrenaline is linked to sour, the taste test could be a useful way to determine which drug to use, a big plus because antidepressants can take several weeks or more to have an effect. And with this disease, time is of the essence--if treated within 3 months of becoming depressed, a person has a very good chance of getting better.

Training young brains to behave

Benedict Carey offers an informative article on brain development in children, and the growth of self control as the prefrontal cortex matures. The article has an excellent interactive graphic that permits you to move a slider and see brain changes during development.

Social exclusion causes unconscious mimicry

Lakin et al. make some interesting observations on our reactions to being socially excluded by others, we are likely to unconsciously start mimicking their behaviors:

Research across various disciplines has demonstrated that social exclusion has devastating psychological, emotional, and behavioral consequences. Excluded individuals are therefore motivated to affiliate with others, even though they may not have the resources, cognitive or otherwise, to do so. The current research explored whether nonconscious mimicry of other individuals—a low-cost, low-risk, automatic behavior—might help excluded individuals address threatened belongingness needs. Our first experiment demonstrated that excluded people mimic a subsequent interaction partner more than included people do. A second experiment showed that individuals excluded by an in-group selectively (and nonconsciously) mimic a confederate who is an in-group member more than a confederate who is an out-group member. The relationship between exclusion and mimicry suggests that there are automatic behaviors people can use to recover from the experience of being excluded. In addition, this research demonstrates that nonconscious mimicry is selective and sensitive to context.

Chill out aids

A few links for calming your mental chatter during these tumultuous financial times:
Worriers Annonymous
Sacred Geometry

Gender gaps widen

A New York Times article by John Tierney describes the work of Schmitt and others:

When men and women take personality tests, some of the old Mars-Venus stereotypes keep reappearing. On average, women are more cooperative, nurturing, cautious and emotionally responsive. Men tend to be more competitive, assertive, reckless and emotionally flat. Clear differences appear in early childhood and never disappear.

What’s not clear is the origin of these differences. Evolutionary psychologists contend that these are innate traits inherited from ancient hunters and gatherers. Another school of psychologists asserts that both sexes’ personalities have been shaped by traditional social roles, and that personality differences will shrink as women spend less time nurturing children and more time in jobs outside the home.

To test these hypotheses, a series of research teams have repeatedly analyzed personality tests taken by men and women in more than 60 countries around the world. For evolutionary psychologists, the bad news is that the size of the gender gap in personality varies among cultures. For social-role psychologists, the bad news is that the variation is going in the wrong direction. It looks as if personality differences between men and women are smaller in traditional cultures like India’s or Zimbabwe’s than in the Netherlands or the United States. A husband and a stay-at-home wife in a patriarchal Botswanan clan seem to be more alike than a working couple in Denmark or France. The more Venus and Mars have equal rights and similar jobs, the more their personalities seem to diverge.

...new data from 40,000 men and women on six continents...suggests that as wealthy modern societies level external barriers between women and men, some ancient internal differences are being revived...biggest changes recorded by the researchers involve the personalities of men, not women. Men in traditional agricultural societies and poorer countries seem more cautious and anxious, less assertive and less competitive than men in the most progressive and rich countries of Europe and North America.

“Humanity’s jaunt into monotheism, agriculturally based economies and the monopolization of power and resources by a few men was ‘unnatural’ in many ways,” Dr. Schmitt says, alluding to evidence that hunter-gatherers were relatively egalitarian. “In some ways modern progressive cultures are returning us psychologically to our hunter-gatherer roots,” he argues. “That means high sociopolitical gender equality over all, but with men and women expressing predisposed interests in different domains. Removing the stresses of traditional agricultural societies could allow men’s, and to a lesser extent women’s, more ‘natural’ personality traits to emerge.”

Cherokee story for a Monday morning...

While I was doing some idle web cruising using StumbleUpon this item came up, which I thought was a good way to frame one basic cognitive therapy technique:

One evening an old Cherokee told his grandson about a battle that goes on inside people.

He said, "My son, the battle is between two wolves inside us all.

One is Evil. It is anger, envy, jealousy, sorrow, regret, greed, arrogance, self-pity, guilt, resentment, inferiority, lies, false pride, superiority, and ego.

The other is Good. It is joy, peace, love, hope, serenity, humility, kindness, benevolence, empathy, generosity, truth, compassion and faith."

The grandson thought about it for a minute and then asked his grandfather: "Which wolf wins?"

The old Cherokee simply replied, "The one you feed."

Neural correlates of Zen meditation

The complete title of the article by Pagoni et al. is “Thinking about Not-Thinking”: Neural Correlates of Conceptual Processing during Zen Meditation. Here is their abstract:

Recent neuroimaging studies have identified a set of brain regions that are metabolically active during wakeful rest and consistently deactivate in a variety the performance of demanding tasks. This “default network” has been functionally linked to the stream of thoughts occurring automatically in the absence of goal-directed activity and which constitutes an aspect of mental behavior specifically addressed by many meditative practices. Zen meditation, in particular, is traditionally associated with a mental state of full awareness but reduced conceptual content, to be attained via a disciplined regulation of attention and bodily posture. Using fMRI and a simplified meditative condition interspersed with a lexical decision task, we investigated the neural correlates of conceptual processing during meditation in regular Zen practitioners and matched control subjects. While behavioral performance did not differ between groups, Zen practitioners displayed a reduced duration of the neural response linked to conceptual processing in regions of the default network, suggesting that meditative training may foster the ability to control the automatic cascade of semantic associations triggered by a stimulus and, by extension, to voluntarily regulate the flow of spontaneous mentation.

Bad mothering, good fathering..

Two interesting pieces of work on the chemistry underlying parental care of children:

Lerch-Haner et al. find in mice that serotonergic function is required for the nurturing and survival of offspring. Mothers with a specific disruption in serotonin neuron development built poor-quality nests and did not keep their offspring huddled together, leaving the litter exposed to the cold. Their litters died within a few days of birth despite adequate nursing. When these mothers' young were fostered by normal mothers immediately after birth, their odds of living rose to normal.

Prudom et al. find in Marmosets (a bi-parental primate) that fathers exposed to isolated scents of their infant displayed a significant drop in serum testosterone levels within 20 min after exposure, enhancing their positive infant care.

YouTube for test tubes...

Something I have been unaware of: A YouTube for scientists called The Journal of Visualized Experiments (JoVE). It is now now being indexed in the popular US National Library of Medicine repositories MEDLINE and PubMed. Many of my experimental successes (more than 15 years ago) were based on extremely subtle manual manipulations of visual receptor cells and their parts. They would have been SO much easier to communicate in this new format.

Our brains try multiple meanings before a word is finished.

Here are fascinating observations from Revill et al.. Their imaging data provides evidence of activation of relevant perceptual brain regions in response to the semantics (meaning) of a word while lexical competition is in process and before the word is fully recognized:

As a spoken word unfolds over time, it is temporarily consistent with the acoustic forms of multiple words. Previous behavioral research has shown that, in the face of temporary ambiguity about how a word will end, multiple candidate words are briefly activated. Here, we provide neural imaging evidence that lexical candidates only temporarily consistent with the input activate perceptually based semantic representations. An artificial lexicon and novel visual environment were used to target human MT/V5 and an area anterior to it which have been shown to be recruited during the reading of motion words. Participants learned words that referred to novel objects and to motion or color/texture changes that the objects underwent. The lexical items corresponding to the change events were organized into phonologically similar pairs differing only in the final syllable. Upon hearing spoken scene descriptions in a posttraining verification task, participants showed greater activation in the left hemisphere anterior extent of MT/V5 when motion words were heard than when nonmotion words were heard. Importantly, when a nonmotion word was heard, the level of activation in the anterior extent of MT/V5 was modulated by whether there was a phonologically related competitor that was a motion word rather than another nonmotion word. These results provide evidence of activation of a perceptual brain region in response to the semantics of a word while lexical competition is in process and before the word is fully recognized.

Development of sharing in human children.

Unlike chimpanzees, young children develop a particular form of other-regarding behaviour, called inequality aversion, between the ages of three and eight. On average, three- and four- year-olds behave selfishly whereas seven- and eight-year-olds prefer situations that remove inequality - within their group, that is. Here is the abstract from Fehr et al, who carried out studies with 229 Swiss boys and girls between 3 and 8 years of age to note changes in other-regarding behavior with age:

Human social interaction is strongly shaped by other-regarding preferences, that is, a concern for the welfare of others. These preferences are important for a unique aspect of human sociality—large scale cooperation with genetic strangers—but little is known about their developmental roots. Here we show that young children's other-regarding preferences assume a particular form, inequality aversion that develops strongly between the ages of 3 and 8. At age 3–4, the overwhelming majority of children behave selfishly, whereas most children at age 7–8 prefer resource allocations that remove advantageous or disadvantageous inequality. Moreover, inequality aversion is strongly shaped by parochialism, a preference for favoring the members of one's own social group. These results indicate that human egalitarianism and parochialism have deep developmental roots, and the simultaneous emergence of altruistic sharing and parochialism during childhood is intriguing in view of recent evolutionary theories which predict that the same evolutionary process jointly drives both human altruism and parochialism.

Symmetrical bodies are the sexiest...an underlying reason

Why do we find someone attractive? The observations of Brown et al. support the idea that we find symmetrical human bodies most attractive, and that this signals underlying genotypic or phenotypic quality. (Across many species and taxa, higher body assymetry is associated with increased morbidity and mortality, decreased fecundity, and other variables linked to natural and sexual selection.) Here is their abstract:

Body size and shape seem to have been sexually selected in a variety of species, including humans, but little is known about what attractive bodies signal about underlying genotypic or phenotypic quality. A widely used indicator of phenotypic quality in evolutionary analyses is degree of symmetry (i.e., fluctuating asymmetry, FA) because it is a marker of developmental stability, which is defined as an organism's ability to develop toward an adaptive end-point despite perturbations during its ontogeny. Here we sought to establish whether attractive bodies signal low FA to observers, and, if so, which aspects of attractive bodies are most predictive of lower FA. We used a 3D optical body scanner to measure FA and to isolate size and shape characteristics in a sample of 77 individuals (40 males and 37 females). From the 3D body scan data, 360° videos were created that separated body shape from other aspects of visual appearance (e.g., skin color and facial features). These videos then were presented to 87 evaluators for attractiveness ratings. We found strong negative correlations between FA and bodily attractiveness in both sexes. Further, sex-typical body size and shape characteristics were rated as attractive and correlated negatively with FA. Finally, geometric morphometric analysis of joint configurations revealed that sex-typical joint configurations were associated with both perceived attractiveness and lower FA for male but not for female bodies. In sum, body size and shape seem to show evidence of sexual selection and indicate important information about the phenotypic quality of individuals.

Stress during pregnancy hard on males

Mueller and Bale offer more information on what stress in female mice during pregnancy can do, particularly to male offspring:

Prenatal stress is associated with an increased vulnerability to neurodevelopmental disorders, including autism and schizophrenia. To determine the critical time window when fetal antecedents may induce a disease predisposition, we examined behavioral responses in offspring exposed to stress during early, mid, and late gestation. We found that male offspring exposed to stress early in gestation displayed maladaptive behavioral stress responsivity, anhedonia, and an increased sensitivity to selective serotonin reuptake inhibitor treatment. Long-term alterations in central corticotropin-releasing factor (CRF) and glucocorticoid receptor (GR) expression, as well as increased hypothalamic–pituitary–adrenal (HPA) axis responsivity, were present in these mice and likely contributed to an elevated stress sensitivity. Changes in CRF and GR gene methylation correlated with altered gene expression, providing important evidence of epigenetic programming during early prenatal stress. In addition, we found the core mechanism underlying male vulnerability may involve sex-specific placenta responsivity... in male placentas but not females. Examination of placental epigenetic machinery revealed basal sex differences, providing further evidence that sex-specific programming begins very early in pregnancy, and may contribute to the timing and vulnerability of the developing fetus to maternal perturbations. Overall, these results indicate that stress experience early in pregnancy may contribute to male neurodevelopmental disorders through impacts on placental function and fetal development.

More on digitial intimacy - MindBlog followers and demographics

No sooner have I done yesterday's posting on the 'ambient intimacy' generated by services like Facebook and Twitter than I find on logging in to my Blogger.com dashboard (menu) page a new icon indicating a feature I have been unaware of, 'followers' of the blog. I added the 'gadget' to the left column of this blog (I'll try anything once), and on reading a bit further discover that it appears to deal only with followers who have blogger accounts. They can choose to have the fact that they are following the blog be either private or have their name listed in the box.

I try not to pay attention to the myriad ways one can monitor a blog's traffic, but when the Scientific American people asked me to join their 'Partner's Network' (see the icon in the left column) they asked me to sign on to the quantcast.com analysis site. If you go to quantcast.com and simply enter mindblog.dericbownds.net in the box, you immediately get a detailed demongraphic analysis of this blog's readers: sex, age, income, and how many addicts, regulars, and passers-by there are.

Our aging brains - impaired suppression of distracting information

This work from Gazzaley et al. strikes WAY to close to home for me, as a description of my own aging (66 year old) brain, and why I get frustrated with the n-back memory exercise. Their abstract:

In this study, electroencephalography (EEG) was used to examine the relationship between two leading hypotheses of cognitive aging, the inhibitory deficit and the processing speed hypothesis. We show that older adults exhibit a selective deficit in suppressing task-irrelevant information during visual working memory encoding, but only in the early stages of visual processing. Thus, the employment of suppressive mechanisms are not abolished with aging but rather delayed in time, revealing a decline in processing speed that is selective for the inhibition of irrelevant information. EEG spectral analysis of signals from frontal regions suggests that this results from excessive attention to distracting information early in the time course of viewing irrelevant stimuli. Subdividing the older population based on working memory performance revealed that impaired suppression of distracting information early in the visual processing stream is associated with poorer memory of task-relevant information. Thus, these data reconcile two cognitive aging hypotheses by revealing that an interaction of deficits in inhibition and processing speed contributes to age-related cognitive impairment.

Digital Intimacy

Several years ago I set up a facebook account, looked up the pages of the students who were taking my seminar course, and at the end of the term told them about my experiment. They were mortified to find the professor had seen their self revelations about their sexual and boozing habits - as anyone on the web could have done. Now my daughter and her friends are broadcasting their latest moods and movements via the FaceBook feed, twitter, etc. This sort of freaks me out, the last thing I want is to surrender the last vestiges of my privacy to the greater web community. But, as Clive Thompson points out in his New York Times Magazine article, this new kind of ambient intimacy makes possible a kind of awareness of others not possible before .

Social scientists have a name for this sort of incessant online contact. They call it “ambient awareness.” It is, they say, very much like being physically near someone and picking up on his mood through the little things he does — body language, sighs, stray comments — out of the corner of your eye. Facebook is no longer alone in offering this sort of interaction online. In the last year, there has been a boom in tools for “microblogging”: posting frequent tiny updates on what you’re doing. ... One of the most popular new tools is Twitter, a Web site and messaging service that allows its two-million-plus users to broadcast to their friends haiku-length updates — limited to 140 characters, as brief as a mobile-phone text message — on what they’re doing. There are other services for reporting where you’re traveling (Dopplr) or for quickly tossing online a stream of the pictures, videos or Web sites you’re looking at (Tumblr). And there are even tools that give your location. When the new iPhone, with built-in tracking, was introduced in July, one million people began using Loopt, a piece of software that automatically tells all your friends exactly where you are.

This is the paradox of ambient awareness. Each little update — each individual bit of social information — is insignificant on its own, even supremely mundane. But taken together, over time, the little snippets coalesce into a surprisingly sophisticated portrait of your friends’ and family members’ lives, like thousands of dots making a pointillist painting. This was never before possible, because in the real world, no friend would bother to call you up and detail the sandwiches she was eating. The ambient information becomes like “a type of E.S.P.,” as Haley described it to me, an invisible dimension floating over everyday life.

You could also regard the growing popularity of online awareness as a reaction to social isolation, the modern American disconnectedness that Robert Putnam explored in his book “Bowling Alone.” The mobile workforce requires people to travel more frequently for work, leaving friends and family behind, and members of the growing army of the self-employed often spend their days in solitude. Ambient intimacy becomes a way to “feel less alone,” as more than one Facebook and Twitter user told me.

What will happen in the next ten years?

Nature magazine asked this question of ten prominent researchers and business people. A common theme emerges: the integration of the worlds of matter and information, whether it be by the blurring of boundaries between online and real environments, touchy-feely feedback from a phone or chromosomes tucked away on databases.