Neural Correlates of Audio-Vocal Behavior: Properties of Anterior Limbic Cortex and Related Areas

Abstract

Most reports concerned with the neural mechanism of sound production in mammals have pointed out that the involvement of cortical structures is restricted to primate species (for reviews e.g. see Jurgens, 1979; Muller-Preuss and Ploog, 1983; Sutton and Jurgens, in press). Furthermore, only in man has it been shown that several neocortical areas are engaged in the generation and control of speech (Penfield and Welch, 1959), whereas in nonhuman primates mostly mesocortical regions take part. These somewhat “older” cortical structures are located mainly around the knee of the corpus callosum, an area here comprehensively described as the anterior limbic cortex (ALC); in particular it is composed of structures such as the anterior cingulate gyrus (ACG), the gyrus subcallosus, the gyrus rectus and the region around the anterior cingulate sulcus, which seems to be a transitional zone between new and older parts of the cortex. The latter is bordered dorsally by medial parts of Brodmann areas 6 and 8, known as the supplementary motor area (SMA). The involvement of the SMA in sound production even in nonhuman primates has been suggested for the squirrel monkey (Kirzinger and Jurgens, 1982) and for macaques (Sutton et al., 1985). Type and extent of involvement in man and primates is still matter of discussion, also in this volume.