Premium
Serial and parallel processing in rhesus monkey auditory cortex
Author(s) -
Rauschecker Josef P.,
Tian Biao,
Pons Timothy,
Mishkin Mortimer
Publication year - 1997
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19970526)382:1<89::aid-cne6>3.0.co;2-g
Subject(s) - tonotopy , auditory cortex , cortex (anatomy) , neuroscience , medial geniculate body , biology , thalamus , anatomy , geniculate , temporal cortex , visual cortex , nucleus , inferior colliculus
Auditory cortex on the exposed supratemporal plane in four anesthetized rhesus monkeys was mapped electrophysiologically with both pure‐tone (PT) and broad‐band complex sounds. The mapping confirmed the existence of at least three tonotopic areas. Primary auditory cortex, AI, was then aspirated, and the remainder of the cortex on the supratemporal plane was remapped. PT‐responses in the caudomedial area, CM, were abolished in all animals but one, in which they were restricted to the high‐frequency range. Some CM sites were still responsive to complex stimuli. In contrast to the effects on CM, no significant changes were detectable in the rostral area, R. After mapping cortex in four additional monkeys, injections were made with different tracers into matched best‐frequency regions of AI, R, and CM. Injections in AI and R led to retrograde labeling of neurons in all three subdivisions of the medial geniculate (MG) nucleus (MGv, MGd, and MGm), as well as nuclei outside MG, whereas CM injections led to only sparse labeling of neurons in a restricted zone of the lateral MGd and, possibly, MGm, in addition to labeling in non‐MG sites. The combined results suggest that MGv sends direct projections in parallel to areas AI and R, which drive PT‐responses in both areas. PT‐responses in area CM, however, appear to be driven by input relayed serially from AI. The direct input to CM from MGd and other thalamic nuclei may thus be capable of mediating responses only to broad‐band sounds. J. Comp. Neurol. 382:89‐103, 1997. © 1997 Wiley‐Liss Inc.