Neuroanthropology

For a greater understanding of the encultured brain and body…

Archive for March 29th, 2008

Meditating makes the brain more compassionate

Posted by gregdowney on March 29, 2008

Blogging on Peer-Reviewed ResearchScientific American‘s Mind & Brain website has a discussion of a recent study of meditation, Meditate on This: You Can Learn to Be More Compassionate. The original research article that this piece is discussing, ‘Regulation of the Neural Circuitry of Emotion by Compassion Meditation: Effects of Meditative Expertise’ by Antoine Lutz, Julie Brefczynski-Lewis, Tom Johnstone, and Richard J. Davidson, is available on-line at the Public Library of Science (here).

The research team investigated the activity of the insula and anterior cingulate cortices, areas implicated in empathetic reactions to others’ suffering, when people voluntarily sought to feel compassion. In other words, the research team looked at whether a set of brain areas which are active when people see other people suffering and feel empathy might be intentionally activated in situations where subjects imagined compassion; could will or conscious thought be used to summon up brain activity that looks like a reaction to suffering that is almost automatic in most people? (Lots of caveats here, but you get the gist.)

In particular, the team was looking at whether compassion meditation might make people more likely to have strong reactions to hearing the signals of another person’s distress; from the abstract, ‘Our main hypothesis was that the concern for others cultivated during this form of meditation enhances affective processing, in particular in response to sounds of distress, and that this response to emotional sounds is modulated by the degree of meditation training.’ Specifically, the research team compared novice meditators to ’16 long-term Buddhist meditators, whom we classified as experts’: ‘Experts had previously completed from 10,000 to 50,000 hours of meditative training in a variety of practices, including compassion meditation, in similar Tibetan traditions (Nyingmapa and Kagyupa).’

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Posted in Emotion, Meditation | 6 Comments »

New neuroscience podcasts and Brazilian racial genomics

Posted by gregdowney on March 29, 2008

Vaughn at Mind Hacks points out several sites with good neurosciences lectures to download on a recent post, Lancet and MNI neuroscience podcasts. The ones from Lancet Neurology can be found here; and the ones from the Montreal Neurological Institute are here. In a post in February, Neurology podcasts – the shocking truth, Vaughn offers still more lectures available online from a number of sources (maybe we should try to do this at Neuroanthropology, especially if we can match Vaughn’s description of one podcast as an ‘excessively thorough lecture given by a voice synthesiser’ — now there’s something for which I can strive!).

On the Lancet Neurology site, there’s a number of good-looking lectures, but many are discussions of the whole volume by editor Helen Frankish. This might be an easy way to get a grip on a wide variety of current research, but they are more likely to be kind of technical for the non-specialist.

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Posted in Human variation, Links | Leave a Comment »

Smell, fear and sensory learning

Posted by gregdowney on March 29, 2008

Blogging on Peer-Reviewed ResearchWen Li, James D. Howard, Todd B. Parrish, and Jay A. Gottfried have a fascinating article in the most recent edition of Science, ‘Aversive Learning Enhances Perceptual and Cortical Discrimination of Indiscriminable Odor Cues.’ The researchers trained subjects to discern between the aroma of chemicals that initially were indistinguishable using electric shocks (!) coupled with one of the two aromas. The research is a great example of perceptual learning, a form of neural enculturation that I think is absolutely essential to understanding cultural difference but little appreciated in anthropology.

Subjects in the experiment were given a test of their ability to discern between very closely related chemicals: ‘On each trial, subjects smelled sets of three bottles (two containing one odorant, the third containing its chiral opposite) and selected the odd stimulus.’ Before the training, subjects selected the odd odor out 33% of the time — no better than random. After the repeated association of one chemical with shocks, subjects’ ability to discriminate the smells improved markedly, showing that negative reinforcement training could ‘enhance perceptual discriminability between initially indistinguishable odors.’ Moreover, the neural representation of the smells changed, as found with fMRI.

From their abstract:

We combined multivariate functional magnetic resonance imaging with olfactory psychophysics to show that initially indistinguishable odor enantiomers (mirror-image molecules) become discriminable after aversive conditioning, paralleling the spatial divergence of ensemble activity patterns in primary olfactory (piriform) cortex. Our findings indicate that aversive learning induces piriform plasticity with corresponding gains in odor enantiomer discrimination, underscoring the capacity of fear conditioning to update perceptual representation of predictive cues, over and above its well-recognized role in the acquisition of conditioned responses. That completely indiscriminable sensations can be transformed into discriminable percepts further accentuates the potency of associative learning to enhance sensory cue perception and support adaptive behavior.

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Posted in Cognitive anthropology, Human variation, Neural plasticity, Perception and the senses | 1 Comment »

 
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