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Abstract:
Abstract: While the study of face perception and
prosopagnosia has revealed substantial information about the neural
organization of object recognition, little attention has been paid
to voice recognition. The present study attempted to dissociate
neural systems associated with voice recognition from those
involved in word processing. We performed functional magnetic
resonance imaging scans of the frontal and temporal lobes of 10
individuals (8 right-handed) while they performed 2-back tasks with
recorded series of words spoken by 6 different voices. The Subjects
were required to perform the task based either on the content of
the speech (WORD), or the voice speaking the word (VOICE). A third
condition using changing tones (TONE) provided a non-speech control
condition. In each condition 25% of the trials were matches.
Volunteers underwent 4-6 scans during which the three conditions
alternated every 42 sec. Analysis of the statistical parametric
maps for the VOICE-WORD comparison indicated that the WORD
condition produced significantly greater activation in the left
inferior frontal gyrus, while VOICE produced significantly more
activation in the right inferior frontal and right middle frontal
gyri. When compared to the TONE condition, both the WORD and VOICE
conditions produced similar distributions of activation albeit with
peak signals at different loci. These results suggest that right
hemisphere frontal and temporal lobe regions engage in the process
of voice processing and that this process relies on non-verbal
auditory analysis.
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