Perceptual categorization of sound spectral envelopes reflected in auditory-evoked N1m.

Magnetic responses to periodic complex sounds with equivalent acoustic parameters except for two diierent fundamental frequencies (F0) and 12 diierent spectral envelopes of vocal, instrumental, and linear shapes were recorded to determine the cortical representation of timbre categorization in humans. Responses at approximately 100 ms (N1m) to vocal and instrumental (nonlinear) sounds were localized signi¢cantly anterior to linear sound responses. N1m source strength for nonlinear sounds was signi¢cantly larger than that for linear sounds, and this diierence was more marked in the left hemisphere than in the right. N1m peak latency only for vocal sounds was not aiected by F0 .P erceptual categorization was re£ected in N1m source strength and location (linear or nonlinear), and in N1m latency (vocal or nonvocal). NeuroReport 16:555^558 � c 2005 Lippincott Williams &W ilkins.