Auditory Cortical Areas in Primates

Our knowledge of auditory areas of cerebral cortex in the primate begins with the published work of David Ferrier (4, 5). Following the experiments of Fritsch and Hitzig on the frontal lobe of the dog, Ferrier found that electrical stimulation of a limited region of the temporal lobe in the monkey resulted in orienting behavior reminiscent of that seen when the animal encounters a sudden novel sound. On the basis of a large series of experiments in monkeys and other mammals, in which he explored electrically much of the exposed surface of the cerebral hemispheres, Ferrier concluded that these movements evoked by stimulation of a restricted region of the superior temporal gyrus (his area 14), or its presumed homolog in nonprimate species, are outward manifestations of the arousal of subjective auditory sensations and that this responsive area is, indeed, a center of auditory sensibility. From more recent studies in the macaque monkey, it would appear that Ferrier’s electrodes did not contact the primary auditory field (A I) directly, but were within one or more of the fields that are contiguous with it on the exposed gyral surface. From these and other studies like them, Ferrier clearly recognized that sensory and motor functions are localized in cerebral cortex and that there are multiple spatial sensory and motor representations within the nervous system. He further concluded that these various cortical regions are intimately tied to one another anatomically and functionally.