Aging - Memory decline, sugar control, and emotional memories

Great.....now I learn another way in which my aging brain can fail to remember - the worsening of glucose regulation with aging permits more glucose spikes which reduce blood flow to the dentate gyrus in our hippocampus (required for new memory formation). Perhaps on the more positive side, memories carry less emotion in older people, apparently because their processing moves towards frontal and away from limbic areas.

Get religious to improve self control?

Here is a curious piece by John Tierney noting the work of Michael McCullouch, who provides evidence that religiosity correlates with higher self-control among adults.

“Brain-scan studies have shown that when people pray or meditate, there’s a lot of activity in two parts of brain that are important for self-regulation and control of attention and emotion,” he said. “The rituals that religions have been encouraging for thousands of years seem to be a kind of anaerobic workout for self-control.”

In a study published by the University of Maryland in 2003, students who were subliminally exposed to religious words (like God, prayer or bible) were slower to recognize words associated with temptations (like drugs or premarital sex). Conversely, when they were primed with the temptation words, they were quicker to recognize the religious words.

What should a heathen like myself do?

Dr. McCullough’s advice is to try replicating some of the religious mechanisms that seem to improve self-control, like private meditation or public involvement with an organization that has strong ideals.

Cleanliness reduces the severity of moral judgements.

From Schnall et al. at the Univ. of Plymouth. Here is their abstract, followed by a bit of explanation:

Theories of moral judgment have long emphasized reasoning and conscious thought while downplaying the role of intuitive and contextual influences. However, recent research has demonstrated that incidental feelings of disgust can influence moral judgments and make them more severe. This study involved two experiments demonstrating that the reverse effect can occur when the notion of physical purity is made salient, thus making moral judgments less severe. After having the cognitive concept of cleanliness activated (Experiment 1) or after physically cleansing themselves after experiencing disgust (Experiment 2), participants found certain moral actions to be less wrong than did participants who had not been exposed to a cleanliness manipulation. The findings support the idea that moral judgment can be driven by intuitive processes, rather than deliberate reasoning. One of those intuitions appears to be physical purity, because it has a strong connection to moral purity.

[In experiment 1 two different groups of participants look at lists of scrambled words before being asked to rate the wrongness of six different moral dilemmas. Half of the words in one of the lists related to the theme of cleanliness and purity (e.g., pure, washed, clean, immaculate, pristine), while the other list contained neutral words. In experiment 2 participants were given an opportunity to physically cleanse themselves after experiencing disgust (a physically disgusting scene from a film).]

Heaven for the Godless?

A piece from Charles M. Blow:

In June, the Pew Forum on Religion and Public Life published a controversial survey in which 70 percent of Americans said that they believed religions other than theirs could lead to eternal life...This threw evangelicals into a tizzy. After all, the Bible makes it clear that heaven is a velvet-roped V.I.P. area reserved for Christians. Jesus said so: “I am the way, the truth and the life: no man cometh unto the Father, but by me.” But the survey suggested that Americans just weren’t buying that...The evangelicals complained that people must not have understood the question. The respondents couldn’t actually believe what they were saying, could they?

So in August, Pew asked the question again. (They released the results last week.) Sixty-five percent of respondents said — again — that other religions could lead to eternal life. But this time, to clear up any confusion, Pew asked them to specify which religions. The respondents essentially said all of them...And they didn’t stop there. Nearly half also thought that atheists could go to heaven — dragged there kicking and screaming, no doubt — and most thought that people with no religious faith also could go.

What on earth does this mean?

One very plausible explanation is that Americans just want good things to come to good people, regardless of their faith.

Rapid perceptual switching...

Jackson et al. examine contradictory perceptions while viewing biological versus moving ambiguous structures. (Try this movie of an ambiguous rotating walker, a figure that randomly alternates between walking in clockwise (CW) and counter-clockwise (CCW) directions.) Percept durations with a light point rotating walker are shorter than for a standard light point walker.

Brain lesions and sprituality

Johnstone and Glass note a correlation between increased spirituality and right parietal lobe lesions, more clear than previously noted correlations with left temporal lobe activity. They suggest this might arise from decreased awareness of the self (leading to sense of transcendence), while reports of spirituality and increased activity of the left temporal lobe might be associated with the experience of specific religious archetypes (religious figures and symbols). (If you click on 'religion' in the left column under 'selected blog categories' you will note a number of differing observations on correlations between spirituality and brain activity.)

Recent research suggests that spiritual experiences are related to increased physiological activity of the frontal and temporal lobes and decreased activity of the right parietal lobe. The current study determined if similar relationships exist between self-reported spirituality and neuropsychological abilities associated with those cerebral structures for persons with traumatic brain injury (TBI). Participants included 26 adults with TBI referred for neuropsychological assessment. Measures included the Core Index of Spirituality (INSPIRIT); neuropsychological indices of cerebral structures: temporal lobes (Wechsler Memory Scale-III), right parietal lobe (Judgment of Line Orientation), and frontal lobes (Trail Making Test, Controlled Oral Word Association Test). As hypothesized, spirituality was significantly negatively correlated with a measure of right parietal lobe functioning and positively correlated (nonsignificantly) with measures of left temporal lobe functioning. Contrary to hypotheses, correlations between spirituality and measures of frontal lobe functioning were zero or negative (and nonsignificant). The data support a neuropsychological model that proposes that spiritual experiences are related to decreased activity of the right parietal lobe, which may be associated with decreased awareness of the self (transcendence) and increased activity of the left temporal lobe, which may be associated with the experience of specific religious archetypes (religious figures and symbols).

Living the Off-Label Life

Further comments on cognition enhancing drugs from Warner, commenting on the Nature essay I mentioned previously.

Genetics of successful placebo response to stress.

Here is a fascinating piece of work from Furmark et al., showing that placebo treatment of stress in subjects with social anxiety disorder (reflected by reducted amygdala activity during public speaking) was successful only in individuals with particular forms of serotonin transporter and tryptophan hydroxylase genes. This demonstrates a link between genetically controlled serotonergic modulation of amygdala activity and placebo-induced anxiety relief. The experiments were done in the context of a study evaluating a potential anti-anxiety drug and matching placebo provided by GlaxoSmithKline.

Placebo may yield beneficial effects that are indistinguishable from those of active medication, but the factors underlying proneness to respond to placebo are widely unknown. Here, we used functional neuroimaging to examine neural correlates of anxiety reduction resulting from sustained placebo treatment under randomized double-blind conditions, in patients with social anxiety disorder. Brain activity was assessed during a stressful public speaking task by means of positron emission tomography before and after an 8 week treatment period. Patients were genotyped with respect to the serotonin transporter-linked polymorphic region (5-HTTLPR) and the G-703T polymorphism in the tryptophan hydroxylase-2 (TPH2) gene promoter. Results showed that placebo response was accompanied by reduced stress-related activity in the amygdala, a brain region crucial for emotional processing. However, attenuated amygdala activity was demonstrable only in subjects who were homozygous for the long allele of the 5-HTTLPR or the G variant of the TPH2 G-703T polymorphism, and not in carriers of short or T alleles. Moreover, the TPH2 polymorphism was a significant predictor of clinical placebo response, homozygosity for the G allele being associated with greater improvement in anxiety symptoms. Path analysis supported that the genetic effect on symptomatic improvement with placebo is mediated by its effect on amygdala activity. Hence, our study shows, for the first time, evidence of a link between genetically controlled serotonergic modulation of amygdala activity and placebo-induced anxiety relief.

Upper limb amputees can sense a rubber hand as their own

A further observation on the brain plasticity shown during the rubber hand illusion (mentioned in the Dec. 24 posting) is made by Ehrsson et al., who find that the illusion can induced in upper limb amputees:

We describe how upper limb amputees can be made to experience a rubber hand as part of their own body. This was accomplished by applying synchronous touches to the stump, which was out of view, and to the index finger of a rubber hand, placed in full view (26 cm medial to the stump). This elicited an illusion of sensing touch on the artificial hand, rather than on the stump and a feeling of ownership of the rubber hand developed. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioural data in the form of misreaching in a pointing task when asked to localize the position of the touch, and physiological evidence obtained by skin conductance responses when threatening the hand prosthesis. Our findings outline a simple method for transferring tactile sensations from the stump to a prosthetic limb by tricking the brain, thereby making an important contribution to the field of neuroprosthetics where a major goal is to develop artificial limbs that feel like a real parts of the body.

Musing on the topic of well-being or happiness...

On seeing this Op-Ed piece by Lyubomirsky in the NYTimes I realized that this is the author, an academic researcher, who has put out a book that I am currently scanning titled "The How of Happiness: A Scientific Approach to Getting the Life You Want." The NYTimes Op-Ed piece notes that the reason that most of us are not more dejected than one might expect by the market meltdown and recession is that the fortunes of virtually everyone have been compromised, and we care more about social comparison, status and rank than about the absolute value of our bank accounts or reputations.

With regard to the book, Ms. Lyubomirsky can not be accused of being a skilled prose stylist, but her writing does offer a meat and potatoes list of behavioral tips on activities that have been shown in double blind studies on fairly large groups of real people to enhance well-being, namely:

Expressing gratitude
Cultivating Optimism
Avoiding over thinking and social comparison
Practicing acts of kindness
Nurturing relationships
Developing strategies for coping.
Learning to forgive
Doing more activities that truly engage you.
Savoring Life’s joys
Committing to your goals
Practicing religion and spirituality
Taking care of your body.

She suggests taking the four of these that seem most congenial to you, and working on those rather than tackling the whole list.

My take on this well-being stuff is that it does boil down to some fairly discrete mental operations, being a matter of executive (frontal lobe) function - to put some things in your mind and not others - images of coherence and well being versus random input from the environment and the old pandora’s box of your past. This is essentially cognitive therapy, letting one thing express rather than another (making a distinction such as: ‘this is a part of my brain that is not working to my advantage’). It does not have to be an energy draining self-coercion of one part of ourselves going to war with another, but rather is a self choosing of one option over another. You are what you spend your time doing.

Hemispheric shift of categorical color perception during brain development.

Franklin et al. show an interesting shift in categorical perception of colors from right to left hemisphere as infants learn the words that distinguish the relevant category boundaries, showing an influence of language on the functional organization of the brain.

Categorical perception (CP) of color is the faster and more accurate discrimination of two colors from different categories than two colors from the same category, even when same- and different-category chromatic separations are equated. In adults, color CP is lateralized to the left hemisphere (LH), whereas in infants, it is lateralized to the right hemisphere (RH). There is evidence that the LH bias in color CP in adults is due to the influence of color terms in the LH. Here we show that the RH to LH switch in color CP occurs when the words that distinguish the relevant category boundary are learned. A colored target was shown in either the left- or right-visual field on either the same- or different-category background, with equal hue separation for both conditions. The time to initiate an eye movement toward the target from central fixation at target onset was recorded. Color naming and comprehension was assessed. Toddlers were faster at detecting targets on different- than same-category backgrounds and the extent of CP did not vary with level of color term knowledge. However, for toddlers who knew the relevant color terms, the category effect was found only for targets in the RVF (LH), whereas for toddlers learning the color terms, the category effect was found only for targets in the LVF (RH). The findings suggest that lateralization of color CP changes with color term acquisition, and provide evidence for the influence of language on the functional organization of the brain.

Sharing today's New York Times

How social status shapes race.

Penner and Saperstein carry out an interesting analysis of data from the National Longitudinal Survey of Youth (NLSY), which contains multiple measures of interviewer-classified and self-identified race over a twenty-year period. Their abstract, followed by one figure from the paper:

We show that racial perceptions are fluid; how individuals perceive their own race and how they are perceived by others depends in part on their social position. Using longitudinal data from a representative sample of Americans, we find that individuals who are unemployed, incarcerated, or impoverished are more likely to be seen and identify as black and less likely to be seen and identify as white, regardless of how they were classified or identified previously. This is consistent with the view that race is not a fixed individual attribute, but rather a changeable marker of status.


Figure - Racial self-identification and cumulative social status, 2002. Source: National Longitudinal Survey of Youth. (A) The percentage of respondents who self-identified as white in 2002, restricted to respondents who identified as white in 1979. (B) The percentage of respondents who identified as black in 2002, restricted to respondents who identified as black in 1979. Ever-incarcerated refers to whether the respondent was ever interviewed while in prison; ever-unemployed refers to whether the respondent was ever unemployed for more than 4 months in a calendar year; and ever-impoverished refers to whether the respondent's household income was ever below the poverty line. Error bars, ± 1SE.

Altering our self-face recognition

In the wake of several recent posts on the rubber hand illusion, which alters our sense of where our hand is in space, I thought this observation by Tsakiris was interesting: multisensory input to our face (Synchronous tactile stimulation while watching another person's face being similarly touched) causes a bias in recognizing our own face. Here is the abstract:

How do I know the person I see in the mirror is really me? Is it because I know the person simply looks like me, or is it because the mirror reflection moves when I move, and I see it being touched when I feel touch myself? Studies of face-recognition suggest that visual recognition of stored visual features inform self-face recognition. In contrast, body-recognition studies conclude that multisensory integration is the main cue to selfhood. The present study investigates for the first time the specific contribution of current multisensory input for self-face recognition. Participants were stroked on their face while they were looking at a morphed face being touched in synchrony or asynchrony. Before and after the visuo-tactile stimulation participants performed a self-recognition task. The results show that multisensory signals have a significant effect on self-face recognition. Synchronous tactile stimulation while watching another person's face being similarly touched produced a bias in recognizing one's own face, in the direction of the other person included in the representation of one's own face. Multisensory integration can update cognitive representations of one's body, such as the sense of ownership. The present study extends this converging evidence by showing that the correlation of synchronous multisensory signals also updates the representation of one's face. The face is a key feature of our identity, but at the same time is a source of rich multisensory experiences used to maintain or update self-representations.

The net generation

Hurt offers a review of Tapscott's recent book "Growing up Digital", which defines the 81 million people born between 1977 to 1997 that make up 27% of the population as the "net generation" (following generations X and Y).

"As the first global generation ever, the Net Geners are smarter, quicker and more tolerant of diversity than their predecessors,” Tapscott writes. “They care strongly about justice and the problems faced by their society and are typically engaged in some kind of civic activity at school, at work or in their communities."

Mr. Tapscott devotes an entire chapter to examining how Net Geners are already using their collective power to transform society — as evidenced by their impact on Barack Obama’s presidential campaign...He documents how Mr. Obama capitalized on interactive social networking sites like Facebook and MySpace that inspired the participation of millions of small donors, while Hillary Rodham Clinton relied on relatively old broadcast-style media like television and e-mail to attract much lower numbers of mostly large donors.

Mr. Tapscott identifies eight norms of many members of the Net Generation: they prize freedom; they want to customize things; they enjoy collaboration; they scrutinize everything; they insist on integrity in institutions and corporations; they want to have fun even at school or work; they believe that speed in technology and all else is normal; and they regard constant innovation as a fact of life.

He cites recent brain-imaging and childhood-development studies to buttress his contention that Internet use by Net Geners has fundamentally changed — and improved — the way their brains are wired. Noting that raw I.Q. scores have been climbing by three points a decade since World War II across racial, income and regional boundaries, Mr. Tapscott asserts that Net Geners are also developing valuable skills that do not show up on standard I.Q. tests.

“Not only do video game players notice more, they have highly developed spatial skills that are useful for architects, engineers and surgeons,” he says.

Men are red, women are green.

Here is a curious bit which I pass on from the Random Samples section of the Dec. 19 Science Magazine, describing the work of researchers at Brown University:

Men are colored like Mars, but women are greenish--and the difference may help explain how people perceive la difference...Cognitive scientist Michael Tarr and grad student Adrian Nestor made the discovery by averaging mug shots of 200 white males and females into a single androgynous face. They then obscured it further with randomly placed red and green pixels.

Three volunteers looked at 20,000 different versions of the image--some redder, others greener--and told the researchers which sex they thought each face represented. The result: Faces with green pixels were tagged as female and those with more red pixels as male. The color of the cheekbones, nose, and sides of the mouth were particularly important to decisions, says Tarr, whose paper is in press in Psychological Science.

Marlene Behrmann, a psychologist at Carnegie Mellon University in Pittsburgh, Pennsylvania, says the fact that people subconsciously recognize the red-green distinction "means there is something evolutionarily and ecologically important about color that extends even into the human central nervous system."

Bach oratorio on period instruments.

Cognitive benefits of a walk in the woods

An article by Berman et al. in Psychological Science (PDF here) shows that immersion in a natural environment leads to more than simply a sense of feeling refreshed, it also recharges our cognitive batteries:

We compare the restorative effects on cognitive functioning of interactions with natural versus urban environments. Attention restoration theory (ART) provides an analysis of the kinds of environments that lead to improvements in directed-attention abilities. Nature, which is filled with intriguing stimuli, modestly grabs attention in a bottom-up fashion, allowing top-down directed-attention abilities a chance to replenish. Unlike natural environments, urban environments are filled with stimulation that captures attention dramatically and additionally requires directed attention (e.g., to avoid being hit by a car), making them less restorative. We present two experiments that show that walking in nature or viewing pictures of nature can improve directed-attention abilities as measured with a backwards digit-span task and the Attention Network Task, thus validating attention restoration theory.

Seasonal Nostalgia

I alternatively want to feel warm and cushy or gag myself with a spoon on watching this.

Knowing where and knowing how to get there - a dissociation in the rubber hand illusion.

Kammers et al. show that during the rubber hand illusion (in which watching a rubber hand being stroked while our own unseen hand is synchronously stroked induces a relocation of the sensed position of our own hand towards the rubber hand) our actual ballistic hand movements resist the illusion. Their abstract contains some useful references:

In the well-known rubber hand illusion (RHI), watching a rubber hand being stroked while one's own unseen hand is synchronously stroked, induces a relocation of the sensed position of one's own hand towards the rubber hand [Botvinick, M., & Cohen, J. (1998). Rubber hands ‘feel’ touch that eyes see. Nature, 391(6669), 756]. As one has lost the veridical location of one's hand, one should not be able to correctly guide one's hand movements. An accurate representation of the location of body parts is indeed a necessary pre-requisite for any correct motor command [Graziano, M. S. A., & Botvinick, M. M. (1999). How the brain represents the body: Insights from neurophysiology and psychology. In D. Gopher, & A. Koriat (Eds.), Attention and performance XVII—Cognitive regulation of performance interaction of theory and application (pp. 136–157)]. However, it has not yet been investigated whether action is indeed affected by the proprioceptive drift towards the rubber hand, nor has the resistance of visual capture in the RHI to new proprioceptive information been assessed. In the present two kinematic experiments, we show for the first time that action resists the RHI and that the RHI resists action. In other words, we show a dissociation between illusion-insensitive ballistic motor responses and illusion-sensitive perceptual bodily judgments. Moreover, the stimulated hand was judged closer to the rubber hand for the perceptual responses, even after active movements. This challenges the view that any proprioceptive update through active movement of the stimulated hand erases the illusion. These results expand the knowledge about representations of the body in the healthy brain, and are in line with the currently most used dissociation between two types of body representations so far mainly based on neuropsychological patients [Paillard, J. (1991). Knowing where and knowing how to get there. In J. Paillard (Ed.), Brain and space (pp. 461–481); Paillard, J. (1999). Body schema and body image: A double dissociation in deafferented patients. In G. N. Gantchev, S. Mori, & J.Massion (Eds.), Motor control, today and tomorrow (pp. 197–214)].