CYTOCHROME-OXIDASE, ACETYLCHOLINESTERASE, AND NADPH-DIAPHORASE STAINING IN HUMAN SUPRATEMPORAL AND INSULAR CORTEX - EVIDENCE FOR MULTIPLE AUDITORY AREAS

The pattern of cytochrome oxidase, acetylcholinesterase, and NADPH-dia phorase activity was studied in the supratemporal plane, the posterior part of the superior temporal gyrus, and the insula of normal human b rains. Five dark cytochrome oxidase regions were found: (i) on Heschl' s gyrus (area TC of von Economo and Koskinas); (ii) on the planum pola re (area TC/TG); (iii) posterior to Heschl's gyrus (within area TA); ( iv) on the posterior convexity of the superior temporal gyrus (within area TA); and (v) on the posterosuperior insula (area IB). More lightl y stained cortex separated these regions (areas IA, TD, and part of TB ). The laminar distribution of cytochrome oxidase activity varied in d ifferent areas. Acetylcholinesterase positive fibers predominated in a rea TC and pyramidal neurons in areas TA and IA and in parts of TB; a mixture of fiber and neuronal staining was found in TC/TG, TD, and IB. NADPH-diaphorase positive profiles included large darkly stained nonp yramidal neurons, mostly in infragranular layers and in subcortical wh ite matter, small faintly stained cells, and a dense array of fibers. The NADPH-diaphorase staining pattern did not vary between areas. The present results suggest that the supratemporal plane, the posterior pa rt of the superior temporal gyrus, and the insula contain at least eig ht putative cortical areas. Comparison with activation studies by othe rs suggest that, apart from the primary auditory area, six other putat ive areas may be auditory whereas one putative area, on posterior insu la, may be vestibular. (C) 1997 Academic Press.