New nerve cell growth in stress-induced social avoidance.

Lagace et al. look at changes in the dentate gyrus region of the hippocampus to probe why some people are resilient to long-term chronic stress while others develop maladaptive functioning. They examined chronic social defeat stress in a mouse model, finding that synthesis of new nerve cells is increased after social defeat stress selectively in mice that display persistent social avoidance. Irradiation that halts formation of these new nerve cells inhibits appearance of social avoidance, suggesting a functional role for adult-generated dentate gyrus neurons. The data show that the time window after cessation of stress is a critical period for the establishment of persistent cellular and behavioral responses to stress and that a compensatory enhancement in neurogenesis is related to the long-term individual differences in maladaptive responses to stress.

The Blues Broaden, but the Nasty Narrows

A great article title from Gable and Harmon-Jones, and yet another study involving students in an introductory psychology course: observations that highly motivated positive and negative emotions go with narrowing of our attentional focus, but either positive or negative low-motivation feelings broaden attention. Their slightly edited abstract:

Positive and negative affects high in motivational intensity cause a narrowing of attentional focus. In contrast, positive affects low in motivational intensity cause a broadening of attentional focus. The attentional consequences of negative affects low in motivational intensity have not been experimentally investigated. A first experiment (using color photographs, selected from the International Affective Picture System) compared the attentional consequences of negative affect low in motivational intensity (sadness) relative to a neutral affective state. Results indicated that low-motivation negative affect caused attentional broadening. A second experiment found that disgust, a high-motivation negative affect not previously investigated in attentional studies, narrowed attentional focus. These experiments support the conceptual model linking high-motivation affective states to narrowed attention and low-motivation affective states to broadened attention.

Thoughts of randomness enhance supernatural beliefs.

Kay et al. do some interesting experiments in which thoughts of randomness are primed in subject by a set of manipulations. They:

...supraliminally primed half the participants with randomness-related words; the other half were primed with words matched in negative valence. To assess the role of arousal, we employed a misattribution paradigm, which involved requiring all participants to swallow a pill ostensibly containing an herbal supplement. Half the participants were told that the pill sometimes induces arousal as a side effect, and half were told that the pill has no side effects. Previous work has shown that the side-effect condition leads participants to attribute the cause of any experienced arousal to this salient source. Hypothesizing that beliefs in supernatural control function, at least in part, to down-regulate the aversive arousal associated with randomness, we expected the randomness primes to increase beliefs in God, but only for those participants not given the opportunity to attribute the cause of their arousal to the ingested pill.

Their observations were that:

...participants primed with randomness-related words exhibited heightened beliefs in spiritual control compared with participants primed with negatively valenced control words. This effect disappeared when participants were given the opportunity to attribute the cause of any arousal they experienced to a pill ingested earlier in the session. 

They take their data to suggest:

...that belief in supernatural sources of control, such as God and karma, may function, in part, to defend against distress associated with randomness, even when the perception of randomness is not related to traumatic events.

Demasculinization of frogs (and men?) by pesticides

Male sperm count has dropped dramatically over the past 50 years (~50% in some areas) and one of the prime suspects is estrogen like compounds, such as the pesticide atrazine, that have been introduced into the environment. Atrazine is one of the most commonly applied agricultural pesticides in the world (and, curiously, male sperm count has dropped more in agricultural than in metropolitan areas). Hays et al now show that at levels of only 2.5 parts per billion it can completely feminize amphibian males.

Strange Maps

Having spent a fair amount of time on the London underground this past summer, I thought this graphic of an imagined world-wide system, shown in the Sunday NYTimes Book Review section,  was intriguing.

An imagined train route from Oslo to Pyongyang, from STRANGE MAPS: An Atlas of Cartographic Curiosities (Viking Studio, paper, $30).

Men's testosterone increases with female ovulation cues

Observations from Miller and Manor:

Adaptationist models of human mating provide a useful framework for identifying subtle, biologically based mechanisms influencing cross-gender social interaction. In line with this framework, the current studies examined the extent to which olfactory cues to female ovulation—scents of women at the peak of their reproductive fertility—influence endocrinological responses in men. Men in the current studies smelled T-shirts worn by women near ovulation or far from ovulation (Studies 1 and 2) or control T-shirts not worn by anyone (Study 2). Men exposed to the scent of an ovulating woman subsequently displayed higher levels of testosterone than did men exposed to the scent of a nonovulating woman or a control scent. Hence, olfactory cues signaling women’s levels of reproductive fertility were associated with specific endocrinological responses in men—responses that have been linked to sexual behavior and the initiation of romantic courtship.

More on the virtues of red wine...

A further rationale for my sipping red wine during and after dinner -  O'Connor notes work showing that red wine does indeed aid the digestion, particularly of dark meats, because it both stimulates digestion and inhibits the formation of harmful oxidized fats.

Fundamental changes in public discourse.

Three recent New York Times pieces have provided a summary of the disintegration of public discourse since the era of Lyndon Johnson. David Carr notes the demise of a short-lived column in The Washington Post on Washington's social life which is symbolic of the passing of the old paradigm, in which

...people with different points of view would assemble in various salons of Georgetown and set aside their differences over an Old Fashioned before the coq au vin was even served...Now the butter knife has been replaced by a machete. People with opposing political points of view are less likely to eat with the loyal opposition at night than to try to dine on them in a quick hit on MSNBC or Fox News... “The dinner party at Ben and Sally’s or Mrs. Graham’s circa 1975 was The Note or Mike Allen blast e-mail of its day,” said David Von Drehle, editor at large for Time and a former editor of The Post’s Style section..."You would go there to see people, try out ideas, figure out what was the interesting next take on the day’s news and where the hot story was headed. But now, you find all that out just by opening up your laptop in the morning.”

Articles by both John Harwood and Paul Krugman chronicle the almost perfect polarization that now characterizes the political scene. Harwood:

...when President Lyndon B. Johnson won passage of Medicare, most of the Democratic majority in Congress and half of the Republicans backed him...Those Democratic and Republican parties no longer exist. The kinds of Southern Democrats who resisted Johnson’s agenda and Northern Republicans who supported it have switched parties; longstanding differences between liberals and conservatives are now reinforced by party affiliation, not blurred by it...What democrats and republicans share is a dedication to party unity as an overriding imperative — and a relentlessly improving track record of achieving it.

And Krugman focuses on:

...the incredible gap that has opened up between the parties. Today, Democrats and Republicans live in different universes, both intellectually and morally...Democrats believe .. what textbook economics says: that when the economy is deeply depressed, extending unemployment benefits not only helps those in need, it also reduces unemployment...the Congressional Budget Office says that aid to the unemployed is one of the most effective forms of economic stimulus, as measured by jobs created per dollar of outlay. [The view of the second ranking senate Republican, in contrast is that:]... unemployment relief “doesn’t create new jobs. In fact, if anything, continuing to pay people unemployment compensation is a disincentive for them to seek new work.”

...the difference between the two universes isn’t just intellectual, it’s also moral...How can the parties agree on policy when they have utterly different visions of how the economy works, when one party feels for the unemployed, while the other weeps over affluent victims of the “death tax”?..bipartisanship is now a foolish dream...Someday, somehow, we as a nation will once again find ourselves living on the same planet. But for now, we aren’t. And that’s just the way it is.

Looking at motor imagery underlying complex skill learning.

During a recent period of rehearsing for the four hands piano recital that I participated in yesterday,* I found myself observing (mentally imaging) the detailed execution of the pieces when I woke during the night or early morning. Such imaging is known to be a central part of learning skilled sequences in athletic and musical performance.  In a bit of fortuitous timing, the most recent issue of PNAS has an article by Miller et al. describing direct observation of this kind of motor imagery:

Imagery of motor movement plays an important role in learning of complex motor skills, from learning to serve in tennis to perfecting a pirouette in ballet. What and where are the neural substrates that underlie motor imagery-based learning? We measured electrocorticographic cortical surface potentials in eight human subjects during overt action and kinesthetic imagery of the same movement, focusing on power in “high frequency” (76–100 Hz) and “low frequency” (8–32 Hz) ranges. We quantitatively establish that the spatial distribution of local neuronal population activity during motor imagery mimics the spatial distribution of activity during actual motor movement. By comparing responses to electrocortical stimulation with imagery-induced cortical surface activity, we demonstrate the role of primary motor areas in movement imagery. The magnitude of imagery-induced cortical activity change was ∼25% of that associated with actual movement. However, when subjects learned to use this imagery to control a computer cursor in a simple feedback task, the imagery-induced activity change was significantly augmented, even exceeding that of overt movement.

*(I have put some rehearsal videos made before the recital here and here, but the final recordings turned out to have technical recording problems and so can't be posted.)

Funny or die

Under the "random curious stuff" category mentioned in MindBlog's title line,  I couldn't resist passing on this satirical gem from funnyordie.com

Funny or Die's Presidential Reunion from Will Ferrell

Measuring consciousness -how an anesthetic puts us to sleep.

Ferrarelli et al. show what is happening when we are zonked out by an anesthetic like the benzodiazepine midazolam. They use an array of EEG electrodes on the head to measure how much the activities of different areas of the cortex are coordinated with each other when a magnetic pulse is applied to stir things up (transcranial magnetic stimulation, or TMS). When we are awake TMS triggers responses in multiple cortical areas lasting for more than 300 ms, during midazolam-induced loss of consciousness, TMS-evoked activity is shorter and more local, i.e. areas of the cortex stop talking to each other. Here is their abstract:

By employing transcranial magnetic stimulation (TMS) in combination with high-density electroencephalography (EEG), we recently reported that cortical effective connectivity is disrupted during early non-rapid eye movement (NREM) sleep. This is a time when subjects, if awakened, may report little or no conscious content. We hypothesized that a similar breakdown of cortical effective connectivity may underlie loss of consciousness (LOC) induced by pharmacologic agents. Here, we tested this hypothesis by comparing EEG responses to TMS during wakefulness and LOC induced by the benzodiazepine midazolam. Unlike spontaneous sleep states, a subject’s level of vigilance can be monitored repeatedly during pharmacological LOC. We found that, unlike during wakefulness, wherein TMS triggered responses in multiple cortical areas lasting for >300 ms, during midazolam-induced LOC, TMS-evoked activity was local and of shorter duration. Furthermore, a measure of the propagation of evoked cortical currents (significant current scattering, SCS) could reliably discriminate between consciousness and LOC. These results resemble those observed in early NREM sleep and suggest that a breakdown of cortical effective connectivity may be a common feature of conditions characterized by LOC. Moreover, these results suggest that it might be possible to use TMS-EEG to assess consciousness during anesthesia and in pathological conditions, such as coma, vegetative state, and minimally conscious state.

Are kids overmedicated?

Zuger reviews a book by Judith Warner on a topic that I and many others have had a knee jerk reflex type opinion on:  "Yes, of course kids are overmedicated by lazy parents and pill popping psychologists."  Warner began her study with that attitude, intending to prove her point,  and found quite the opposite.   She:

...sallied forth to interview all the pushy parents, irresponsible doctors and overmedicated children she could find — and lo, she could barely find any. After several years of dead ends, missed deadlines and worried soul-searching, she was forced to reconsider her premise and start all over again.

“A couple of simple truths have become clear,” she writes with the passion of a new convert. “That the suffering of children with mental health issues (and their parents) is very real. That almost no parent takes the issue of psychiatric diagnosis lightly or rushes to ‘drug’ his or her child; and that responsible child psychiatrists don’t, either. And that many children’s lives are essentially saved by medication, particularly when it’s combined with evidence-based forms of therapy.”

The power of touch.

I've been meaning to point to an interesting article by Benedict Carey on our voluntary momentary touches that can - whether an exuberant high five, a warm hand on the shoulder, or a creepy touch to the arm — communicate an even wider range of emotion than gestures or expressions, and sometimes do so more quickly and accurately than words. He focuses on work of Dacher Keltner, Hertenstein, and collaborators, the subject of previous posts (PDF here, also, enter Keltner in the search box in the left column). In their experiments volunteers tried to communicate a list of emotions by touching a blindfolded stranger. The participants were able to communicate eight distinct emotions, from gratitude to disgust to love, some with about 70 percent accuracy. Here is their abstract:

The study of emotional communication has focused predominantly on the facial and vocal channels but has ignored the tactile channel. Participants in the current study were allowed to touch an unacquainted partner on the whole body to communicate distinct emotions. Of interest was how accurately the person being touched decoded the intended emotions without seeing the tactile stimulation. The data indicated that anger, fear, disgust, love, gratitude, and sympathy were decoded at greater than chance levels, as well as happiness and sadness, 2 emotions that have not been shown to be communicated by touch to date. Moreover, fine-grained coding documented specific touch behaviors associated with different emotions.

A forthcoming publication from Kraus, Huang, and Keltner finds that, with a few exceptions, good basketball teams tended to be touchier than bad ones. Another slightly edited clip:

If a high five or an equivalent can in fact enhance performance, on the field or in the office, that may be because it reduces stress. A warm touch seems to set off the release of oxytocin, a hormone that helps create a sensation of trust, and to reduce levels of the stress hormone cortisol...In the brain, prefrontal areas, which help regulate emotion, can relax, freeing them for another of their primary purposes: problem solving. In effect, the body interprets a supportive touch as “I’ll share the load.”...“We think that humans build relationships precisely for this reason, to distribute problem solving across brains,” said James A. Coan, a a psychologist at the University of Virginia. “We are wired to literally share the processing load, and this is the signal we’re getting when we receive support through touch.”

The same is certainly true of partnerships, and especially the romantic kind, psychologists say. In a recent experiment, researchers led by Christopher Oveis of Harvard conducted five-minute interviews with 69 couples, prompting each pair to discuss difficult periods in their relationship...The investigators scored the frequency and length of touching that each couple, seated side by side, engaged in... "it looks so far like the couples who touch more are reporting more satisfaction in the relationship,” he said.  Again, it’s not clear which came first, the touching or the satisfaction. But in romantic relationships, one has been known to lead to the other. Or at least, so the anecdotal evidence suggests.

Food and Flying

An interesting tidbit from the Random Samples section of the 19 Feb. issue of Science Magazine:

German scientists have figured out why tomato juice tastes better aboard an airplane than on the ground (and coffee tastes worse). Low atmospheric pressure dampens the experience of sweet and salty tastes whereas sour comes through unchanged and bitter is slightly intensified, says flavor chemist Andrea Burdack-Freitag of the Frauenhofer Institute for Building Physics in Holzkirchen.

She and her colleagues asked 30 taste testers to rate their perceptions of different foods and wine while sitting in a partial Airbus A310 in a chamber with adjustable pressure. At ground pressures, tasters perceived tomato juice as musty, but at a low pressure typical in flight they found it fruitier, with cool notes. The complex aromas picked up by the nose that give coffee its flavor were barely perceived at low pressure, unmasking caffeine's bitterness, Burdack-Freitag says. Lufthansa's catering arm, which sponsored the study, wants to use the data to improve its menus.

Damage to our amygdala can eliminate monetary loss aversion

Here is an interesting open access article from Ralph Adolphs and his colleagues:

Losses are a possibility in many risky decisions, and organisms have evolved mechanisms to evaluate and avoid them. Laboratory and field evidence suggests that people often avoid risks with losses even when they might earn a substantially larger gain, a behavioral preference termed “loss aversion.” The cautionary brake on behavior known to rely on the amygdala is a plausible candidate mechanism for loss aversion, yet evidence for this idea has so far not been found. We studied two rare individuals with focal bilateral amygdala lesions using a series of experimental economics tasks. To measure individual sensitivity to financial losses we asked participants to play a variety of monetary gambles with possible gains and losses. Although both participants retained a normal ability to respond to changes in the gambles’ expected value and risk, they showed a dramatic reduction in loss aversion compared to matched controls. The findings suggest that the amygdala plays a key role in generating loss aversion by inhibiting actions with potentially deleterious outcomes.

Oxytocin may improve autism

I have done a large number of posts on behavioral effects of oxytocin, the 'trust hormone', notably in human studies that use an oxytocin inhaler (enter oxytocin in the blog search box in the left column to display them).  Recent studies are now suggesting that when some autistic people (who have difficulty interacting with others) inhale oxytocin, they began looking at people in the eye and recognizing social concepts like fairness in a computer game.

Behavioral Addictions in the proposed DSM-V

I am increasingly amazed at the creeping "pathologicalization" of behaviors that vary a bit from the 'normal'.  Almost any repetitive activity or habit could be construed as a behavioral addition (Tiger Wood's golf and sex?).  I might well be considered an alcoholic sociopathic sex addict by some, given my one a day knockout happy hour drink, my extremely active libido, and my ability to observe the generation of my emotional and social behaviors and halt or detach from them when necessary. I though this article by Constance Holden had some interesting chunks, which I pass on here (see also the related previous post yesterday on the Bonkers institute):

"...proposed revisions for the American Psychiatric Association's (APA's) Diagnostic and Statistical Manual of Mental Disorders (DSM) include for the first time "behavioral addictions"—a change some say is long overdue and others say is still premature...

"Sex addiction" has received a lot of press lately, but O'Brien [University of Pennsylvania, chair of the addictions work group for DSM-V] says his work group found "no scientific evidence" that sex qualifies. APA psychiatrist Darrel Regier, co-chair of the DSM task force, says "it's not clear that reward circuitry is operative in the same way as in addictive areas." Nonetheless, a near equivalent may make it into the sexual disorders section of DSM: That work group is proposing a controversial new diagnosis of "hypersexual disorder."

The DSM teams have also tussled with the often-blurry line between addictions and compulsions. "I used to think [addictions] overlapped with OCD [obsessive-compulsive disorder]," says O'Brien. But new data from both brain-imaging and treatment studies suggest "more dissimilarities than similarities."

In another major change, O'Brien's group recommends dropping categories of "abuse" and "dependence" and labeling all problems major and minor as substance "use disorders" (or "disordered gambling"). Since the late 1980s, says O'Brien, "numerous large population studies" have shown there's no "breakpoint" where "abuse" becomes something more serious. He also says the term "dependence" only implies physiological dependence, which is not the same as the psychological obsession of addiction.

Some longtime addiction researchers, such as psychiatrist Victor Hesselbrock of the University of Connecticut, Farmington, have qualms about the direction DSM is moving. Hesselbrock believes behavioral addictions are dicey territory and prefers to limit the term "addiction" to substances, which are "pathogens we can identify." He also objects to fusing all drinking problems into "alcohol use disorder." Hesselbrock says he and others think there are proven subcategories of alcoholism that would aid both in treatment and discovering causes. "When you do a one-size-fits-all type of classification system," he says, "that will fit a lot of people but not so well."

Our thalamus goes to sleep before our cerebral cortex

Magnin et al. have recorded thalamic and cortical activities simultaneously in epileptic patients chronically implanted with intracerebral electrodes to address the issue of when these two regions of the brain go to sleep. (The thalamus is the main gateway through which information from our bodies flows to the cortex.) They find, contrary to the common view, that the thalamus deactivates well before the cortex during sleep onset, leaving the cortex to spin its stories without input from the world during a hypnagogic or half-awake state during which illusions or inspirations sometimes occur, giving us the impression that it is taking us longer to get to sleep than is actually the case. Here is their abstract:

Thalamic and cortical activities are assumed to be time-locked throughout all vigilance states. Using simultaneous intracortical and intrathalamic recordings, we demonstrate here that the thalamic deactivation occurring at sleep onset most often precedes that of the cortex by several minutes, whereas reactivation of both structures during awakening is synchronized. Delays between thalamus and cortex deactivations can vary from one subject to another when a similar cortical region is considered. In addition, heterogeneity in activity levels throughout the cortical mantle is larger than previously thought during the descent into sleep. Thus, asynchronous thalamo-cortical deactivation while falling asleep probably explains the production of hypnagogic hallucinations by a still-activated cortex and the common self-overestimation of the time needed to fall asleep.

Depression's Upside

Jonah Lehrer (a really bright guy, author of "How We Decide", "Proust was a Neuroscientist", and the blog "The Frontal Cortex") has made his first New York Times Magazine contribution, an excellent article on depression that focuses on work of Andrews and Thomson who suggest that depression is a evolved behavior that has the function of removing us from normal daily behaviors to focus on and hopefully solve a pressing life issue.  They describe their model as the "analytic-rumination hypothesis." A few clips from the article:

Several studies found an increase in brain activity (as measured indirectly by blood flow) in the VLPFC of depressed patients. Most recently, a paper to be published next month by neuroscientists in China found a spike in “functional connectivity” between the lateral prefrontal cortex and other parts of the brain in depressed patients, with more severe depressions leading to more prefrontal activity. One explanation for this finding is that the hyperactive VLPFC underlies rumination, allowing people to stay focused on their problem...the reliance on the VLPFC doesn’t just lead us to fixate on our depressing situation; it also leads to an extremely analytical style of thinking. That’s because rumination is largely rooted in working memory, a kind of mental scratchpad that allows us to “work” with all the information stuck in consciousness. When people rely on working memory — and it doesn’t matter if they’re doing long division or contemplating a relationship gone wrong — they tend to think in a more deliberate fashion, breaking down their complex problems into their simpler parts.

The bad news is that this deliberate thought process is slow, tiresome and prone to distraction; the prefrontal cortex soon grows exhausted and gives out. Andrews and Thomson see depression as a way of bolstering our feeble analytical skills, making it easier to pay continuous attention to a difficult dilemma. The downcast mood and activation of the VLPFC are part of a “coordinated system” that, Andrews and Thomson say, exists “for the specific purpose of effectively analyzing the complex life problem that triggered the depression.” If depression didn’t exist — if we didn’t react to stress and trauma with endless ruminations — then we would be less likely to solve our predicaments. Wisdom isn’t cheap, and we pay for it with pain.

....the analytic-rumination hypothesis is merely the latest attempt to explain the prevalence of depression. There is, for example, the “plea for help” theory, which suggests that depression is a way of eliciting assistance from loved ones. There’s also the “signal of defeat” hypothesis, which argues that feelings of despair after a loss in social status help prevent unnecessary attacks; we’re too busy sulking to fight back. And then there’s “depressive realism”: several studies have found that people with depression have a more accurate view of reality and are better at predicting future outcomes. While each of these speculations has scientific support, none are sufficient to explain an illness that afflicts so many people. The moral, Nesse says, is that sadness, like happiness, has many functions.

To say that depression can be useful doesn't mean it is always going to be useful. While it might explain patients reacting to an acute stressor, it can’t account for those whose suffering has no discernible cause or whose sadness refuses to lift for years at a time.

In the last section of the article Lehrer notes a number of studies indicating a correlation of depression with better artistic creativity and improved analytical abilities.

Asymptomatic Depression - hidden disease and untapped market

The distinguished Dr. Methodius Bonkers has emailed me to point out his institute's most recent study.  It is a hoot.