Lateralization Of Speech Comprehension, Journal Of Neuroscience

Main Category: Neurology / Neuroscience
Also Included In: Psychology / Psychiatry
Article Date: 06 Aug 2008 - 4:00 PDT

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Speech comprehension involves both brain hemispheres, but the extent to which the hemispheres have overlapping functions is not clear. One hypothesis suggests that the hemispheres differ in their processing of temporal and spectral information.

To test this, Obleser et al. presented spoken words to human subjects while measuring cortical activity using functional magnetic resonance imaging. Using noise vocoding, a technique that permits independent manipulation of frequency and spectral information, voice recordings were degraded in five steps in each dimension, resulting in 25 conditions.

Comprehensibility declined with degradation in each dimension, and cortical activation correlated with comprehensibility. All conditions activated the anterior superior temporal cortex bilaterally, but the peak and extent of activation in the two hemispheres varied: the right hemisphere was more sensitive than the left to spectral variation, whereas the left hemisphere was more sensitive to temporal variation.

The results indicate mild lateralization of these elements of speech processing.

Journal of Neuroscience

The Journal of Neuroscience is the official journal of the Society for Neuroscience. The Journal publishes papers on a broad range of topics of general interest to those working on the nervous system.

Journal of Neuroscience

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