Tuesday, December 19, 2006

An auditory-motor 'mirror" system is engaged by positive emotions.

More on mirror systems from Warren et al in Journal of Neuroscience. Edited clips from their paper:

Social interaction relies on the ability to react to communication signals. Although cortical sensory–motor "mirror" networks are thought to play a key role in visual aspects of primate communication, evidence for a similar generic role for auditory–motor interaction in primate nonverbal communication is lacking.

In this functional magnetic resonance imaging (fMRI) study, the authors investigated cortical regions responsive to both the perception of human vocalizations and the voluntary generation of facial expressions. In four auditory–perceptual conditions, subjects listened passively, without overt motor response, to nonverbal emotional vocalizations conveying two positive-valence emotions, amusement and triumph, and two negative-valence emotions, fear and disgust. Use of nonverbal, rather than verbal, vocalizations optimized recognizability of emotional content and avoided confounds of phonological and verbal content. In a facial movement condition, subjects performed voluntary smiling movements in the absence of auditory input. They hypothesized that cortical regions showing combined auditory–perceptual and motor responses would be located within premotor and motor cortical regions.


Figure legend: Brain regions demonstrating auditory–motor mirror responses. A shows regions (red) displaying a significant modulatory effect of emotion category on perceptual activation. B shows regions (light green) displaying significant activation during voluntary facial movements (motor > baseline). C, A masked inclusively in B shows regions (dark green) displaying both a significant modulatory effect of emotion category on perceptual activation and significant activation during voluntary facial movements.


Figure legend: Correlations with emotional valence and arousal in brain regions demonstrating auditory–motor mirror responses. Left, Regions (green) displaying both a significant modulatory effect of emotion category on perceptual activation and significant activation during voluntary facial movements as shown in the figure above. Right, Regions demonstrating a significant positive correlation between hemodynamic responses and emotional valence (red), emotional arousal (blue), or both (purple).

The authors demonstrated that a network of human premotor cortical regions activated during facial movement is also involved in auditory processing of affective nonverbal vocalizations. Within this auditory–motor mirror network, distinct functional subsystems respond preferentially to emotional valence and arousal properties of heard vocalizations. Positive emotional valence enhanced activation in a left posterior inferior frontal region involved in representation of prototypic actions, whereas increasing arousal enhanced activation in presupplementary motor area cortex involved in higher-order motor control. Their findings demonstrate that listening to nonverbal vocalizations can automatically engage preparation of responsive orofacial gestures, an effect that is greatest for positive-valence and high-arousal emotions. The automatic engagement of responsive orofacial gestures by emotional vocalizations suggests that auditory–motor interactions provide a fundamental mechanism for mirroring the emotional states of others during primate social behavior.

Motor facilitation by positive vocal emotions suggests a basic neural mechanism for establishing cohesive bonds within primate social groups.

Monday, December 18, 2006

Sleep deprivation slows the generation of new nerve cells

An interesting finding from Mirescu et al.... It is known that prolonged sleep deprivation is stressful, has adverse effects on cognitive performance and health, and raises corticosterone levels. Their work looks at new nerve cell formation (neurogenesis) in the rat hippocampus, which is central to cognitive performance. They show "that sleep deprivation inhibits adult neurogenesis at a time when circulating levels of corticosterone are elevated. Moreover, clamping levels of this hormone prevents the sleep deprivation-induced reduction of cell proliferation. The recovery of normal levels of adult neurogenesis after chronic sleep deprivation occurs over a 2-wk period and involves a temporary increase in new neuron formation. This compensatory increase is dissociated from glucocorticoid levels as well as from the restoration of normal sleep patterns. Collectively, these findings suggest that, although sleep deprivation inhibits adult neurogenesis by acting as a stressor, its compensatory aftereffects involve glucocorticoid-independent factors."

Sunday, December 17, 2006

The Meerkat wars and synchronicity

It is the year of the Meerkats. These engaging foot long denizens of the Kalahari desert show behaviors that mirror the best and the worst in our society (they steal, they fight, they cheat on their partners), and they have been the subjects of numerous television programs. Now, the Sunday NYTimes points out, just as we have had two Truman Capote movies within a short interval, two full length documentary films on Meekats are about to appear in competition, one from Discovery Films with Animal Planet, the other from BBC Films and the Weinstein company.

Saturday, December 16, 2006

The decline of civility and etiquette on the web.

Having been the recipient of some rather amazing invective comments on this blog (which I didn't permit to be published), not to mention that the majority of comments on the blog are now spam which I have to prevent from being posted, I have to pass on this piece in David Pogues weekly emailing associated with the circuits section of the NY Times.

Whatever Happened to Online Etiquette?

"Dear David, first off i would like to tell you that you are full of **** and did not research the zune enough to know your facts.

(Here follows a list of 'mistakes' made by Pogue)

Pogue then writes:

The deeper we sail into the new online world of communications, the sadder I get about its future. I'm OK with criticism, I'm fine with disagreement, I'm perfectly capable of handling angry mail. That's not the issue here (although my teenage correspondent above was, in fact, wrong about every single one of his points). I've even accepted personal attacks as part of the job. I'm a columnist; the heat comes with the kitchen. But what's really stunning is how hostile *ordinary* people are to each other online these days. Slashdot and Digg.com are extremely popular sites for tech fans. Each discussion begins with the presentation of an article or Web page--and then opens up the floor for discussion.

Lately, an increasing number of the discussions devolve into name-calling and bickering. Someone might submit, say, this item to Digg:

685 diggs. "AWESOME astronomy poem." (posted by MetsFan 3 days ago) Twinkle, twinkle, little star, how I wonder what you are.
Up above the world so high, like a diamond in the sky,
Twinkle, twinkle, little star, how I wonder what you are.

Before long, the people's feedback begins, like this:

by baddude on 12/11/06
What's yr problem, moron. You already said it's a star, why would you then wonder what it is. Get a clue, or a life.
by neverland2 on 12/11/06
Dugg down as inaccurate. Stars do not twinkle. It's the shifting atmosphere that causes an apparent twinkle. Or were you stoned all through science class?
by mrobe on 12/11/06
yo neverland2--It's a poem, idiot. Nobody's claiming that stars twinkle. Ever heard of poetic license? Honestly, the intellectual level of you people is right up there with a gnat's.
...and so on.

What's worse is that the concentration of the nasty people increases as the civil ones get fed up and leave.

What's going on here?
My current theories:
* On the Internet, you're anonymous. Since you don't have to face the person you're dumping on, you don't see any reason to display courtesy.
* On the Internet, you're anonymous. You worry that your comments might get lost in the shuffle, so you lay it on thick to enhance your noticeability.
* The open toxicity is all part of the political climate. We've learned from the Red state-Blue state talking heads that open hostility can pass for meaningful conversation.
* Young people who spend lots of time online are, in essence, replacing in-person social interactions with these online exchanges. With so much less experience conversing in the real world, they haven't picked up on the value of treating people civilly. That is, they haven't yet hit the stage of life when getting things like friends, a spouse and a job depend on what kind of person you are.
* Many parents haven't been teaching social skills (or haven't been around to teach them) for years, but Web 2.0 is suddenly making it apparent for the first time. ("Web 2.0" describes sites like Digg and Slashdot, where the audience itself provides material for the Web site.)
I'd give just about anything to hear what 15-year-old Josh's parents would say if they knew how little respect he holds for adults (let alone the English language). Then again, maybe they wouldn't be surprised a bit.

The real shame, though, is that the kneejerk "everyone else is an idiot" tenor is poisoning the potential the Internet once had. People used to dream of a global village, where maybe we can work out our differences, where direct communication might make us realize that we have a lot in common after all, no matter where we live or what our beliefs.

But instead of finding common ground, we're finding new ways to spit on the other guy, to push them away. The Internet is making it easier to attack, not to embrace.

Maybe as the Internet becomes as predominant as air, somebody will realize that online behavior isn't just an afterthought. Maybe, along with HTML and how to gauge a Web site's credibility, schools and colleges will one day realize that there's something else to teach about the Internet: Civility 101.

A "mind reading" prosthesis for autistic people?

Another clip from the NYTimes Magazine "Ideas" issue:

"The Emotional-Social Intelligence Prosthesis, developed by Rana el Kaliouby and Rosalind Picard, consists of a small camera mounted on a cap or glasses that monitors a conversation partner’s facial expressions and feeds the data into a hand-held computer. Software tracks the movement of facial features and classifies them using a coding system developed by the psychologist Paul Ekman, which is then correlated with a second taxonomy of emotional states created by the Cambridge autism researcher (and Ali G cousin) Simon Baron-Cohen. Almost instantaneously, the computer crunches each raised eyebrow and pucker of the lips, giving a whispered verdict about how the person is feeling. (Another version of the device, meant to be used separately, points back at users, allowing them to better understand — and perhaps modify — the face they present to the world.)" (CLICK to enlarge image below).

Friday, December 15, 2006

Sporno

I can't resist passing on David Haskell's piece in the NYTimes magazine "Ideas" issue in its entirety.

When approached to write an article about the homoerotic subtext of sports for Out magazine this spring, the journalist Mark Simpson feared the subject was old news. “There wasn’t much of a point,” he says, “since sport was already the new gay porn.” Indeed, with the publication of a Dolce & Gabbana underwear campaign featuring Italian soccer players glistening in a dank locker room, the phenomenon had gone well beyond subtext. All that was lacking was a name, and it didn’t take Simpson very long to invent it: sporno.

Sports, of course, have always celebrated physical form. What has changed, Simpson argues, is how we look at men. Thanks to what might be called the Abercrombie effect, the male body has become increasingly aestheticized — or “metrosexualized,” as Simpson would have it (he invented that term too) — and male imagery, particularly in fashion advertising, has become more overtly sensual. Considering that sports is visual, masculine and (like porn) geared mostly to men, Simpson was not surprised to find male athletes — even, or perhaps especially, heterosexual ones — grooming their physical image and “fetishizing themselves.”

The arrival of what Simpson calls “equal opportunity flirts” like the soccer players David Beckham and Freddie Ljungberg, who dabble in gay iconography and openly embrace their gay fans, lends sporno a celebrity cachet. (Simpson calls sporno stars like Ljungberg, whose physical assets are abundantly featured in Calvin Klein underwear ads, “young hustlers.”) Among professional sports organizations, the French national rugby team has pursued its sporno status most aggressively. The team’s annual calendars, Simpson notes, include photo shoots in which “there is no pretense that this is anything but hyperhomoerotic.” Indeed, some images are but a few soap bubbles away from pure pornography.

Psychological Neoteny

An interesting idea in the NYTimes Ideas issue from Bruce Charlton, a doctor and psychology professor at Newcastle University in Britain. What looks like immaturity — or in Charlton’s kinder terms, the “retention of youthful attitudes and behaviors into later adulthood” — is actually a valuable developmental characteristic, which he calls psychological neoteny. "So, the next time you see a mother of three head-banging to death metal or a 50-year-old man sporting a faux-hawk, don’t laugh...In a recent issue of Medical Hypotheses, a journal he edits, Charlton argues that unlike previous, more settled societies that could afford to honor a narrow and well-defined worldview (that is, a “mature” one), modern life is tumultuous and ever-changing. Accordingly, it rewards those who retain a certain plasticity of mind and personality. In a psychological sense, some contemporary individuals never actually become adults."

Thursday, December 14, 2006

Being hungry makes you smarter

Ghrelin is a hormone released by the gut when the absence of food is sensed. It is known to act on the hypothalamus in endocrine and metabolic regulation. Horvath's laboratory reports that making mice 'biochemically hungry' with ghrelin injections improves their performance in maze and other intelligence tests. From their abstract: "circulating ghrelin enters the hippocampus and binds to neurons of the hippocampal formation, where it promotes dendritic spine synapse formation and generation of long-term potentiation. These ghrelin-induced synaptic changes are paralleled by enhanced spatial learning and memory."

This suggests that a great way to prepare for an examination or demanding performance might be, according to Christopher Shea in the NYTimes comment on this work, "Go in mildly hungry, not carbo-loaded for endurance, and snack to maintain that edgy state. Such advice, applied on a national scale, might help save our schools. Since overweight kids have suppressed ghrelin levels, Horvath theorizes that perhaps the obesity epidemic has contributed to declining test scores and other American educational woes."

The Eyes of Honesty

Continuing with another nugget from last Sunday's NYTimes magazine... In the psychology department at Newcastle University, there is a coffee station where people can help themselves, so long as they leave money in the tray. Contributions were disappointing until a picture of a flower above the station was replaced by a picture of staring eyes. During weeks the eyes rather than the flowers were above the station, people contributed 2.7 times more for coffee and tea. Apparently even the feeling of being watched was enough to encourage people to behave more honestly. The paper describing this effect paper prompted a British police department in Birmingham to slap posters of eyes around the city as part of a campaign called “We’ve Got Our Eyes on Criminals.” The researchers are studying the campaign to see if the posters have an effect on things like car crime and vandalism.

Wednesday, December 13, 2006

Homophily on the web - serendipity as antidote?

Another item from last Sunday's NYTimes magazine "Ideas" issue relevant to how our human minds organize themselves.....

Homophily refers to our inexorable tendency to link up with one another in ways that confirm rather than test our core beliefs. This trend is accentuated on "web sites like Facebook and MySpace, which tend to bring birds of a feather together. Meanwhile, chains of recommendations (“if you liked . . . ”) on sites like Amazon reinforce our original preferences even as they claim to expand our horizons." Social software designers who are behind sites such as there are questioning "how much they should encourage homophily and how much they want to mix it up."

What kind of software design might encourage “serendipity” to counter focusing on the familiar? " One information-technology specialist described a feature he would add to Facebook called “the Stretch,” which would help students “find a group of people a little different” from themselves. Someone else brought up the online book cataloger LibraryThing’s UnSuggester, which identifies the book least likely to share a library with the book you mention."

Tuesday, December 12, 2006

Digital Maoism


Jaron Lanier has put an essay on edge.org that is most fascinating. His description of "Digital Maoism" is one of the important ideas of 2006 listed in last Sunday's New York Times Magazine.

"What we are witnessing today is the alarming rise of the fallacy of the infallible collective. Numerous elite organizations have been swept off their feet by the idea. They are inspired by the rise of the Wikipedia, by the wealth of Google, and by the rush of entrepreneurs to be the most Meta. Government agencies, top corporate planning departments, and major universities have all gotten the bug.

There is a pedagogical connection between the culture of Artificial Intelligence and the strange allure of anonymous collectivism online. Google's vast servers and the Wikipedia are both mentioned frequently as being the startup memory for Artificial Intelligences to come....George Dyson has wondered if such an entity already exists on the Net, perhaps perched within Google. My point here is not to argue about the existence of Metaphysical entities, but just to emphasize how premature and dangerous it is to lower the expectations we hold for individual human intellects.

The beauty of the Internet is that it connects people. The value is in the other people. If we start to believe that the Internet itself is an entity that has something to say, we're devaluing those people and making ourselves into idiots."

Steven Johnson's comment in the New York Times summary: "In the essay, Lanier grouped everything from his personal Wikipedia entry to “American Idol” under the umbrella of digital Maoism, and many of the responses to the article by assorted Internet luminaries observed that Lanier had elided important differences between these systems to make his point. The entirety of Wikipedia, for instance, is most certainly a collective undertaking, but many articles are written and edited by small numbers of individuals. Wikipedia may be not too far from the historical reality of Maoism itself: a system propagandized with the language of collectivism that was, in practice, actually run by a small power elite.

In any case, culture and technology are increasingly reliant on the hive mind — and whatever its faults, Lanier’s broadside helps us consider the consequences of this momentous development. A swarm of connected human minds is a fantastic resource for tracking down software bugs or discovering obscure gems on the Web. But if you want to come up with a good idea, or a sophisticated argument, or a work of art, you’re still better off going solo."

Brain imaging of intuition during perceptual discovery

Volz and von Cramon at the Max Planck Institute for Human Cognitive and BrainSciences in Leipzig, Germany, have done an interesting piece of work on imaging intuition, reported in the Journal of Cognitive Neuroscience. Here is their abstract:

"According to the Oxford English Dictionary, intuition is "the ability to understand or know something immediately, without conscious reasoning." Most people would agree that intuitive responses appear as ideas or feelings that subsequently guide our thoughts and behaviors. It is proposed that people continuously, without conscious attention, recognize patterns in the stream of sensations that impinge upon them. What exactly is being recognized is not clear yet, but we assume that people detect potential content based on only a few aspects of the input (i.e., the gist). The result is a vague perception of coherence which is not explicitly describable but instead embodied in a "gut feeling" or an initial guess, which subsequently biases thought and inquiry. To approach the nature of intuitive processes, we used functional magnetic resonance imaging when participants were working at a modified version of the Waterloo Gestalt Closure Task. Starting from our conceptualization that intuition involves an informed judgment in the context of discovery, we expected activation within the median orbito-frontal cortex (OFC), as this area receives input from all sensory modalities and has been shown to be crucially involved in emotionally driven decisions. Results from a direct contrast between intuitive and nonintuitive judgments, as well as from a parametric analysis, revealed the median OFC, the lateral portion of the amygdala, anterior insula, and ventral occipito-temporal regions to be activated."


The figure above indicates some of the task and stimuli conditions used. In the object condition, participants were presented with fragmented black-and-white line drawings of common objects which were subsequently fragmented with which differed in their potential to mask the drawing. In the nonobject condition, participants were presented with meaningless fragmented black-and-white line drawings. The upper left panel (A) shows an example of a coherent trial (violin), the upper right panel (B) an example of an incoherent trial. Stimuli were presented for 400 msec and participants had 2 sec to indicate whether the fragmented line drawing depicted a possible object (left response button) or an impossible object (right response button). Stimuli were neither presented repeatedly nor were images concurrently presented in different levels of fragmentation within one individual session. Participants were encouraged to base their decision on an "initial guess" whether or not the drawing was coherent.


This next figure shows MRI data. Group-averaged activations are shown on coronal, sagittal, and axial slices of an individual brain normalized and aligned to the Talairach stereotactic space. The upper left panel shows the imaging results of the direct contrast between trials that participants judged to be meaningful with trials that participants judged to be meaningless. The upper right panel shows the imaging results from the correlational analysis of the median OFC's (mOFC) time course. In the lower panel, imaging results from the parametric analysis are shown that used a performance-dependent regressor (i.e., the percentage of correct answers per level).

The data suggest that activation within the median orbito-frontal cortex reflects intuitive processing, while activation within ventral occipito-temporal regions reflects object recognition processes.

Monday, December 11, 2006

The Buddha and viscoelastic foam

Here from "The Monastery Store" is just the thing for all you sitting meditators who get sore backs, tailbones, and hip joints from attempting to sit for extended periods on classical meditation cushions containing natural fibers like kapok or buckwheat. They develop lumps that put even more stress on your spine. So, the Buddhist monks at Zen Mountain Monastery have come up with a viscoelastic foam cushion that always retains its original shape. (I still fail to understand why some meditation purists insist that a sitting posture unnatural and painful to most westerners is an essential element of the discipline. I find that a plain old chair is adequate for my limited excursions towards a more quiet mind.)

Guide to brain health

I received a review copy of "The Dana Guide to Brain Health", Dana Press, softcover, 2006, and I guess for the freebie should make a few comments. It is a cobbling together of contributions from 104 contributors edited by Floyd E. Bloom, M. Flint Beal, and David J. Kupfer, establishment guys with lots of credentials. William Saffire (Charman of the Dana Foundation board of directors), in the introduction says "This book is for amateurs like most of us...." It is meant to be the major home health reference on the brain. Such a source sounds good in principle, but I found myself wondering how a steelworker in Flint Michigan worried about his grandmother's stroke could deal with such a flatly written and encyclopedic effort. The huge volumne is not very approachable or friendly. He or she would pick up this book wanting perhaps to know something about strokes, and have to read though a long table of contents to figure out that Part IV "Conditions of the Brain and Nervous System", section 18, parts C59 and C60 had the word stroke in their title. To be
fair, if you get as far as the third section "How to read this book" it says you should look in the index. There you find a very long list of computer generated page and cross references. I'm not sure how our steelworker would deal with all the choices presented. If he or she simply entered "stroke" in google or any other search engine more engaging information from authoritative sources would immediately appear.

On the positive side, Part IV does present a comprehensive list of the basic ways that brains can go wrong, and this alone makes such a compliation worthwhile. Perhaps the volume will prove useful to those who are not computer literate (so why include a CD that adds absolutely nothing to the book?). I guess my take is that is book is a noble idea that in practice is not going to yield the benefits that its sponsors hope for.

Friday, December 08, 2006

Plagarism - how long does a phrase have to be?

I have to pass on some choice bits of an essay by Charles Isherwood in last Sunday's New York Times, occasioned by the flap over Ian McEwen having included some phrases on hospital life in his novel "Atonement" that were similar to those used by romance novelist Lucilla Andrews. (Letters in support of McEwan from heavyweights Margaret Atwood, Kazuo Ishiguro, John Updike, Zadie Smith, Martin Amis and Thomas Pychon have recently been published in the London Daily Telegraph. They point out that Shakespeare, Petrach, and Tolstoy also "stole" material from other sources.)

Isherwood wonders how long a phrase has to be before it becomes actionable: "Oh, dear! Looking back I must apologize for my use of the phrase “best-selling novel,” the very same words Mr. Cowell employed in describing “Atonement.” I am aghast. I should have said “Mr. McEwan’s novel ‘Atonement,’ which flew off the shelves like a massive flock of birds heading southward in the gloaming over the windswept moors.” Or something like that, to differentiate my description from Mr. Cowell’s. A grave mistake....Wait a minute. “Grave mistake” sounds eerily familiar. Egad! So does “eerily familiar.” I must get back to you in a few hours, after an exhaustive Google search that will doubtless allow me to credit any and all authors who have used those phrases."

"The string of scandals seems...a symptom of a shift in cultural attitudes toward the meaning and uses of personal experience. We are living in an age marked by a heightened sensitivity to the idea of one’s own life, and one’s own words, as a commodity with prospective commercial value. In earlier times, it was only writers and other artists who were expected to make profitable use of their everyday experience; the rest of us couldn’t hope to make a dime from the upheavals of existence...How things have changed. With the rise of so-called reality-based entertainment and the surging popularity of the memoir as a literary form, it now seems that everybody’s life is a yet-to-be-developed television property or a memoir waiting to spring from the laptop, uncontaminated by the greedy depredations of the artist. The rush for self-fulfillment and self-expression that characterized the “Me” decade of the 1970s has evolved into a desire for maximum self-exploitation and self-commercialization in these early years of the 21st century, which might be dubbed the “Buy Me” decade. We’d be fools to let someone make a profit off our own backs, and so as a culture we become exercised at the idea of a writer making money by making use of experience or words not entirely his own."

Isherwood quotes Malcolm Gladwell: “The ethics of plagiarism have turned into the narcissism of small differences,” he wrote. “Because journalism cannot own up to its heavily derivative nature, it must enforce originality on the level of the sentence.”

Isherwood: "It’s easy to see how such continued enforcement could create a climate antithetical to the kind of free ferment that artists need. Fiction writers are treasured precisely because they can transmute the unruly dross of daily experience — whether it is their own or that of a guy they once knew or a figure from tabloid headlines — into narratives that have a pleasing shape and pattern and give us insight into our lives. If our lives — and dare I say even our words — are to be our sovereign property, how many of us will really be able to make meaning from them that enriches the world?"

Thursday, December 07, 2006

Brain correlates of visual consciousness

Lau and Passingham report interesting experiments using "relative blindsight" that try to distinguish brain regions essential to visual performance from those involved also in subjective visual consciousness. Here are some edited clips from that work:

Blindsight refers to the phenomenon that, after a lesion to the primary visual cortex, a subject can exhibit above-chance performance in detecting or discriminating visual stimuli in a forced-choice setting, despite the lack of acknowledged consciousness of the stimuli. In some instances, blindsight subjects can perform at an impressively high level of accuracy (>80%) in the forced-choice task, even when the subjects believe that they are guessing. This potentially high level of performance makes blindsight an interesting case study for visual consciousness, because it indicates that it is consciousness, but not the basic capacity to process information, that is completely abolished.

Attempts to unequivocally demonstrate blindsight in normal observers have proved to be controversial, so instead of looking for a complete dissociation of performance and visual consciousness as in the case of blindsight, the authors set out to look for a relative difference ("relative blindsight") in the level of visual consciousness in two conditions in which performance levels are matched. These conditions can be created by using a psychophysical paradigm based on metacontrast masking, shown in Figure 1. In metacontrast masking, a figure that overlaps with the contour of the target is presented after the target. Discrimination performance for a target stimulus decreases and then increases as the temporal distance between the target and a metacontrast mask increases gradually; this distance is referred to as stimulus onset asynchrony (SOA).


Fig. 1. Visual discrimination task with metacontrast masking measured to demonstrate the phenomenon of relative blindsight. The stimuli were presented on a black background. The mask overlaps with part of the contour of the target without leaving gaps or overlapping with the target spatially. After the presentation of the target and the mask, the participants were first asked to decide whether a diamond or a square was presented. Then they had to indicate whether they actually saw the target or whether they simply guessed the answer. Shown in the brackets are the durations of each stimulus.

For the SOA points at 33 and 100 ms, the performance levels (i.e., accuracy rates for the square vs. diamond discrimination) were very similar. However, the subjective judgment of consciousness differed in that at the earlier SOA point volunteers were more likely to claim to have just guessed the answers. Thus the subjective level of consciousness can differ in the absence of a difference of performance levels.


Fig. 2 Activity in the mid-DLPFC reflects visual consciousness (long SOA > short SOA). The activity in this area is higher in the long SOA condition than in the short SOA condition, despite the fact that the two conditions did not yield different discrimination accuracy. There were, however, more trials during which the stimuli were classified by the participants as consciously seen in the long SOA condition than in the short SOA condition. This area was the only one found to be activated in this comparison; parietal activity did not differ significantly even at liberal thresholds.


To identify the brain areas where activity reflected discrimination performance in general, they also analyzed the fMRI results by comparing correct and incorrect trials, combining short SOA and long SOA trials. They found widespread activations in the ventral prefrontal, premotor, parietal, and temporal cortices. The pattern of these activations resembled that in a so-called frontal–parietal network, typically reported in previous studies of visual consciousness. VLPFC, ventrolateral prefrontal cortex; IPS, intraparietal sulcus; MTG, middle temporal gyrus.


Fig. 3 Activations reflecting performance in general (correct trials > incorrect trials). Activations were found in these areas when correct trials were compared against incorrect trials, combining all trials of both SOA conditions.

Although activity in the parietal cortex was found to be related to performance in general, it did not significantly differ between the conditions in which the subjective criteria for conscious perception differed. ...This seems to differ from the results of many previous NCC studies, which have found parietal activity to be as significant as the prefrontal activity, if not more so. The authors argue that it is possible that some of those previously reported activations in the parietal cortex may reflect performance, given that a difference in consciousness level is typically associated with a difference in performance. The potential role of the prefrontal cortex might be further clarified by giving the task used in the present study to patients with lesions that include the mid-DPLFC. Such a study would help contribute further to our understanding of the role of the prefrontal cortex in subjective conscious perception.

Wednesday, December 06, 2006

How the aging brain compensates to preserve language functions

Wingfield and Grossman report in Journal of Neurophysiology their studies of how language comprehension typically remains well preserved in normal aging, in spite of the fact that aging brings with it declines in sensory function, both in vision and in hearing, as well as a general slowing in a variety of perceptual and cognitive operations. They start by reviewing language processing regions of the brain that have been identified both through studies of brain damage and neuroimaging. This figure shows some relevant areas:


Figure 1 description: Within a broad perisylvian region, deficits in language production have been shown to be associated with damage to the ventral inferior frontal cortex (vIFC), which includes Broca's area, and deficits in language comprehension associated with damage to the posterior lateral temporal cortex (PLTC), a part of which is commonly referred to as Wernicke's area. This early picture was completed by discovery of a white-matter tract, the arcuate fasciculus, connecting these two regions. The aphasic syndromes of Broca's aphasia, Wernicke's aphasia, and conduction aphasia were thus neatly accounted for by damage to, or disconnections between, these centers and pathways. These three components of the core sentence processing region colored are shown in blue, with the arcuate fasciculus represented by the connecting blue double-headed arrow. As first implied by the effects of focal brain damage, this core network for sentence processing has been confirmed and more exactly specified by neuroimaging studies in healthy adults. The resource network involves at least several frontal cortical regions and extends to include right hemisphere structures as well as subcortical structures. The left hemisphere structures associated with the recruitment of working-memory and executive resources include dorsolateral prefrontal cortex (dlPFC) and dorsal portion of left inferior frontal cortex (dIFC). Regions in the right hemisphere include PLTC and dIFC. These regions are shown in red.

Winglield and Grossman proceed to present data from their own and other studies that support a compensation hypothesis to explain how declining cell numbers and cortical volumes in these language areas are compensated for by recruitment of other areas. A number of imaging studies contrasting performance by healthy young and older adults have shown a major difference in observed patterns of neural activation when young and older adults are asked to perform the same cognitive task. In general, there is a shift from more focal activation in young adults to more widespread patterns of activation in older adults. This pattern has been observed in a number of cognitive domains, from encoding pictures to studies of episodic memory.

Activity of the core sentence processing network (blue in the above figure) and the resource network (red) during complex sentence comprehension was followed and performance level measured in a number of experiments.


Figure 2 shows regional brain activation contrasts during sentence comprehension for young adults, elderly good comprehenders, and elderly poor comprehenders. A: areas activated by young adults to a greater degree than the elderly good comprehenders. B: areas activated by elderly good comprehenders to a greater degree than young adults. C: areas activated to a greater degree by elderly good comprehenders than by elderly poor comprehenders. D: areas activated to a greater degree by elderly poor comprehenders than by elderly good comprehenders.

In A, young adults were producing a significantly greater degree of activation than the older adults in the posterolateral temporal-parietal cortex in the left hemisphere. This region is thought to support a short-term auditory-phonological buffer that retains information transiently during the course of processing. B. the compensation hypothesis would lead one to expect to see the successful older adults recruit other brain regions to maintain their successful performance. This contrast can be revealed by subtracting the activation levels in the young adults from the older adults' activations. The consequences of this subtraction are shown in the two brain renderings in B, where one sees these successful older adults showing significant upregulation in two areas. One of these is increased activity in the dorsal portion of left inferior frontal cortex. This area is thought to be important for maintaining and rehearsing stored verbal information in working memory. Successful older adults also showed additional activation in the right posterolateral temporal-parietal region. The data illustrate the involvement of a network of cortical areas upregulated in support of sentence processing beyond the left perisylvian core sentence-processing area. In particular, the network upregulates by augmenting working-memory resources needed to support sentence processing.

These studies offer a window on the strategic recruitment of critical brain regions by older adults in response to otherwise limited working-memory resources not seen during sentence comprehension in young adults. They show that older adults augment regional brain activation within the language-processing system both spatially and temporally to help compensate for age-related neuronal changes.

Tuesday, December 05, 2006

Terror Management and Religious Belief

Jonas and Fisher (J. Pers. Soc. Psychol. 91, 553; 2006) conduct three different studies that find that people emphasizing intrinsic religious beliefs (emphasizing meaning and value) are more buffered against thoughts of mortality when reminded of dying (news of terrorist attacks) than people who emphasize extrinsic religios beliefs (searching for safety and solice).

Their complete abstract: "Terror management theory suggests that people cope with awareness of death by investing in some kind of literal or symbolic immortality. Given the centrality of death transcendence beliefs in most religions, the authors hypothesized that religious beliefs play a protective role in managing terror of death. The authors report three studies suggesting that affirming intrinsic religiousness reduces both death-thought accessibility following mortality salience and the use of terror management defenses with regard to a secular belief system. Study 1 showed that after a naturally occurring reminder of mortality, people who scored high on intrinsic religiousness did not react with worldview defense, whereas people low on intrinsic religiousness did. Study 2 specified that intrinsic religious belief mitigated worldview defense only if participants had the opportunity to affirm their religious beliefs. Study 3 illustrated that affirmation of religious belief decreased death-thought accessibility following mortality salience only for those participants who scored high on the intrinsic religiousness scale. Taken as a whole, these results suggest that only those people who are intrinsically vested in their religion derive terror management benefits from religious beliefs."

Monday, December 04, 2006

How to define happiness....?


Excerpting from an article by Reichhardt (Nature 444, 418-419; 23 November 2006) and an editorial (pp 401-402) in the same issue of nature:
Is happiness a single emotion or a personality trait? A physical state, with characteristic brain-wave patterns and biomarkers? Is it simply the absence of unhappiness, or something else? ... This new science has yet to provide a compelling account of how happiness is created. Instead, for obvious methodological reasons, it concentrates on what it correlates with. But it is not clear that changing those correlates by dictat would necessarily produce the desired effect. People may be happy spending time with their children, but forcing parents to spend more time this way would not necessarily overjoy everyone involved. Expressing gratitude makes people happier; a politeness police, probably, would not.

There is further debate as to whether trying to do something about people's happiness is feasible in principle. Some researchers favour the idea that people have a 'hedonic setpoint' that stays remarkably constant in the face of bouquets and brickbats. Such a setpoint need not in principle be unalterable, but its alteration might require an approach with a pharmacological component, raising the problem that one of the things we value about happiness is its authenticity. Another is its autonomy. Governments may guarantee citizens freedom in their pursuit of happiness, but we bridle against the idea of its ever being enforced.

Carol Ryff (University of Wisconsin) is responsible for perhaps the most ambitious well-being research project on happiness ever conducted, the Midlife in the United States, or MIDUS II, study...Ryff hopes to find out whether well-being and ill-being (depression and so on) have distinct biological correlates, or whether they are at opposite ends of the same psychological spectrum. One of her previous studies on a group of 135 older women assessed on biomarkers such as cortisol and waist–hip ratio, suggested that the biological correlates of well-being and ill-being are largely distinctive6. That's one issue MIDUS II will investigate more fully.

Ryff likes to distinguish between hedonic well-being (moods and feelings) and eudaimonic well-being, which is more concerned with factors such as having purpose in life, continued personal growth and development, and good relationships with others. In fact, Ryff rarely uses the term 'happiness'. Perhaps that's because the more scientists learn, the less precise the term has become.

That's roughly where the science of happiness stands right now — still wrestling with its own terminology. Ryff has little time for the fluffier aspects of positive psychology, which she dismisses as "a lot of PR". But one thing she and other well-being researchers can agree on is the nature of the question, "We're going after it in a serious way," she says. "In the final analysis, it's an empirical question."

(By the way, the Smiley Face is made from nanotubes of DNA; see Rothermund, Nature 440, 297–302; 2006)

Friday, December 01, 2006

Just thinking about money changes you.

"The Psychological Consequences of Money" by Vohs et. al. in the Nov 17 issue of Science and an accompanying commentary by Burgoyne and Lee report on nine different experiments that show "that even quite trivial exposure to the idea of money (for example, unscrambling phrases about money or reading an essay about money aloud) changes the goals and behavior of test subjects (none of the student participants in the study realized that it was about money)...it brings about a self-sufficient orientation in which people prefer to be free of dependency and dependents. Reminders of money, relative to nonmoney reminders, led to reduced requests for help and reduced helpfulness toward others. Relative to participants primed with neutral concepts, participants primed with money preferred to play alone, work alone, and put more physical distance between themselves and a new acquaintance...The self-sufficient pattern helps explain why people view money as both the greatest good and evil. As countries and cultures developed, money may have allowed people to acquire goods and services that enabled the pursuit of cherished goals, which in turn diminished reliance on friends and family. In this way, money enhanced individualism but diminished communal motivations, an effect that is still apparent in people's responses to money today."