Discrimination of speech‐like contrasts in the auditory thalamus and cortex

Nina Kraus, Therese McGee, Thomas Carrell, Cynthia King, Thomas Littman, Trent Nicol
1994 Journal of the Acoustical Society of America  
The neurophysiologic discrimination of acoustic contrasts was investigated as reflected by the mismatch negativity (MMN) response. Evoked responses were recorded from guinea pig thalamus (medial geniculate nucleus) and epidural surface in response to synthesized speech contrasts/ga/- da/ and /ba/-/wa/. From the caudomedial portion of the medial geniculate nucleus, /ba/-/wa/ elicited a strong mismatch response, whereas/ga/-/da/did not. Neither stimulus contrast elicited an MMN from the ventral,
more » ... r primary, portion of medial geniculate. Both stimulus contrasts elicited an MMN from the midline surface. Neither contrast elicited an MMN from the surface over the temporal lobe. Results indicate a hierarchy of processing of the spectrotemporal changes which characterize formant transitions. Also, results indicate that the nonprimary portions of the auditory pathway contribute substantially to the MMN. PACS numbers: 43.64.Sj
doi:10.1121/1.411282 pmid:7983281 fatcat:hfq42sjzwnepddsoseblvlfcuy