IDEAS FOR CLASSROOM USE

The existence of special perceptuo-motor skills in certain individuals presents many puzzling questions for the cognitive neurosciences. One such ability whose cerebral substrate remains essentially unknown is absolute pitch (also called "perfect pitch"), a relatively rare ability that refers to a long-term internal representation for the pitch of tones in the musical scale, typically manifested behaviorally by the ability to identify by the name of the musical note the pitch of any sound without reference to another sound, or by the ability to produce a given musical tone on demand. In contrast, relative pitch, which is well-developed among most trained musicians, refers to the ability to make pitch judgments about the relation between notes, such as within a musical interval. The term "functional brain imaging" refers to a number of different techniques for mapping activity in the brain in response to external stimuli or during sensory, perceptual, or cognitive events. Positron emission tomography is a technique for producing cross-sectional images of the body after ingestion and systemic distribution of safely metabolized positron-emitting agents. The images are essentially functional or metabolic, since the ingested agents are metabolized in various tissues. Fluorodeoxyglucose and H(sub2)O(sup15) are common agents used for cerebral applications, and in cerebral applications of central importance to the technique is the fact that changes in the cellular activity of the brains of normal, awake humans and unanesthetized laboratory animals are invariably accompanied by changes in local blood flow and also changes in oxygen consumption. Magnetic resonance imaging is a technique involving images produced by mobile protons of a tissue excited by the application of a magnetic field, and when used in functional cerebral imaging, the basis of the technique is that it images very small metabolic, blood-flow, and perfusion-diffusion changes in vivo, in real time, and with no risk to the subject. ... ...

Zatorre et al (5 authors atMcGill University, CA) report a study of the neural basis of human absolute pitch using both structural and functional brain imaging techniques (magnetic resonance imaging and positron emission tomography). Although there were some localization differences between absolute pitch possessors and control non- absolute-pitch musicians when responding to musical tones, the results as a whole bring the authors to suggest that absolute pitch may not be associated with a unique pattern of cerebral activity, but rather may depend on the recruitment of a specialized network involved in the retrieval and manipulation of verbal-tonal associations.

QY: Robert J. Zatorre (md37@musica.mcgill.ca)

(Proc. Natl. Acad. Sci. US 17 Mar 98 v95:p3172)

(Science-Week 24 Apr 98)

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