Afferents to the cortical larynx area in the monkey.

In 3 squirrel monkeys (Saimiri sciureus) horseradish peroxidase was injected into the cortical larynx area within the lower sensorimotor face cortex. Retrogradely labeled cells were found in a continuous band extending all along the upper bank of the Sylvian fissure from Broca's area rostrally to the parietal association cortex (area 7) caudally. In addition, labeled cells were found in the ventrolateral prefrontal cortex, orbital cortex, anterior cingulate gyrus, supplementary motor area, insula and inferior temporal gyrus. Subcortically, labeled neurons were situated in the substantia innominata, basolateral amygdaloid nucleus, lateral and posterior hypothalamus, the thalamic nuclei ventralis lateralis, ventralis posteromedialis, medialis dorsalis, centralis lateralis, centralis inferior, parafascicularis and pulvinaris, the periventricular gray, reticular formation, nucl. annularis, nucl. centralis superior (Bechterew) and locus coeruleus. Many of these structures are connected with the cortical larynx area reciprocally. The possible phonatory role of some of them is discussed.