November 30, 2010

Your brain on culture

The burgeoning field of cultural neuroscience is finding that culture influences brain development, and perhaps vice versa.

(November, 2010)  When an American thinks about whether he is honest, his brain activity looks very different than when he thinks about whether another person is honest, even a close relative. That’s not true for Chinese people. When a Chinese man evaluates whether he is honest, his brain activity looks almost identical to when he is thinking about whether his mother is honest.

That finding — that American and Chinese brains function differently when considering traits of themselves versus traits of others (Neuroimage, Vol. 34, No. 3) — supports behavioral studies that have found that people from collectivist cultures, such as China, think of themselves as deeply connected to other people in their lives, while Americans adhere to a strong sense of individuality.

The study also shows the power of cultural neuroscience, the growing field that uses brain-imaging technology to deepen the understanding of how environment and beliefs can shape mental function. Barely heard of just five years ago, the field has become a vibrant area of research, and the University of Michigan, the University of California, Los Angeles, and Emory University have created cultural neuroscience centers. In addition, in April a cultural neuroscience meeting at the University of Michigan attracted such psychology luminaries as Hazel Markus, PhD, Michael Posner, PhD, Steve Suomi, PhD, and Claude Steele, PhD, to discuss their work in the context of cultural neuroscience.


November 24, 2010

Jet lagged and forgetful? It’s no coincidence

(November 24, 2010)  Chronic jet lag alters the brain in ways that cause memory and learning problems long after one’s return to a regular 24-hour schedule, according to research by University of California, Berkeley, psychologists.

Twice a week for four weeks, the researchers subjected female Syrian hamsters to six-hour time shifts – the equivalent of a New York-to-Paris airplane flight. During the last two weeks of jet lag and a month after recovery from it, the hamsters’ performance on learning and memory tasks was measured.

As expected, during the jet lag period, the hamsters had trouble learning simple tasks that the hamsters in the control group aced. What surprised the researchers was that these deficits persisted for a month after the hamsters returned to a regular day-night schedule.

What’s more, the researchers discovered persistent changes in the brain, specifically within the hippocampus, a part of the brain that plays an intricate role in memory processing. They found that, compared to the hamsters in the control group, the jet-lagged hamsters had only half the number of new neurons in the hippocampus following the month long exposure to jet lag. New neurons are constantly being added to the adult hippocampus and are thought to be important for hippocampal-dependent learning, Kriegsfeld said, while memory problems are associated with a drop in cell maturation in this brain structure.

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November 22, 2010

Mindfulness practice leads to increases in regional brain gray matter density

(November 22, 2010)  Therapeutic interventions that incorporate training in mindfulness meditation have become increasingly popular, but to date, little is known about neural mechanisms associated with these interventions. Mindfulness-Based Stress Reduction (MBSR), one of the most widely used mindfulness training programs, has been reported to produce positive effects on psychological well-being and to ameliorate symptoms of a number of disorders. Here, we report a controlled longitudinal study to investigate pre-post changes in brain gray matter concentration attributable to participation in an MBSR program. Anatomical MRI images from sixteen healthy, meditation-naïve participants were obtained before and after they underwent the eight-week program. Changes in gray matter concentration were investigated using voxel-based morphometry, and compared to a wait-list control group of 17 individuals. Analyses in a priori regions of interest confirmed increases in gray matter concentration within the left hippocampus. Whole brain analyses identified increases in the posterior cingulate cortex, the temporo-parietal junction, and the cerebellum in the MBSR group compared to the controls. The results suggest that participation in MBSR is associated with changes in gray matter concentration in brain regions involved in learning and memory processes, emotion regulation, self-referential processing, and perspective taking.

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