Friday, November 19, 2004

Neuroscience of music. In the new issue of Scientific American, UC Irvine neurobiologist Norman Weinberger looks at how the brain processes music. Surveying the research in his and others' labs, Weinberger examines how our brain "retunes" itself to various kinds of musical input and how we've evolved our response to music. "An imaging experiment in 2001 by Anne Blood and Zatorre of McGill sought to better specify the brain regions involved in emotional reactions to music. This study used mild emotional stimuli, those associated with people's reactions to musical consonance versus dissonance. Consonant musical intervals are generally those for which a simple ratio of frequencies exists between two tones. An example is middle C (about 260 hertz, or Hz) and middle G (about 390 Hz). Their ratio is 2:3, forming a pleasant-sounding "perfect fifth" interval when they are played simultaneously. In contrast, middle C and C sharp (about 277 Hz) have a "complex" ratio of about 8:9 and are considered unpleasant, having a "rough" sound. What are the underlying brain mechanisms of that experience? PET (positron emission tomography) imaging conducted while subjects listened to consonant or dissonant chords showed that different localized brain regions were involved in the emotional reactions. Consonant chords activated the orbitofrontal area (part of the reward system) of the right hemisphere and also part of an area below the corpus callosum. In contrast, dissonant chords activated the right parahippocampal gyrus. Thus, at least two systems, each dealing with a different type of emotion, are at work when the brain processes emotions related to music. How the different patterns of activity in the auditory system might be specifically linked to these differentially reactive regions of the hemispheres remains to be discovered. In the same year, Blood and Zatorre added a further clue to how music evokes pleasure. When they scanned the brains of musicians who had chills of euphoria when listening to music, they found that music activated some of the same reward systems that are stimulated by food, sex and addictive drugs." [Boing Boing] 11:44:45 AM   comments[]   Are You A Comfort Addict? Do you find yourself unsatisfied, but unable to work out why? Do you find yourself nodding during Fight Club when Tyler Durden tells his recruits that their struggle is a philosophical one... only to be dismayed with his idea of a solution? Is everything okay, but nothing great? You could well be a comfort addict. [kuro5hin.org] 11:28:16 AM   comments[]

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