Afferent and efferent connections of the cortical accommodation area in the cat

Abstract

Accommodative responses were evoked by microstimulation of a circumscribed area in the lateral suprasylvian (LS) cortex of the cat. We studied anatomical connections of this area with WGA-HRP. We identified an accommodation-related area by systematic microstimulation of the LS cortex in each of nine cats. Accommodative and pupillary responses were monitored by an infrared optometer and a pupillometer, respectively. WGA-HRP was injected into the accommodation-related area where accommodative responses were elicited with low-intensity microstimulation, but pupillary responses were not evoked. Retrogradely labeled cells were found mainly in ipsilateral areas 17, 18 and 19, the pulvinar, the lateral posterior nucleus of the thalamus (LP) and the contralateral LS area. Fewer labeled cells were found in ipsilateral areas 20 and 21, the ventral lateral suprasylvian area (VLS), the splenial visual area (SVA) and the lateral geniculate nucleus (LGN). Anterogradely labeled terminals were located mainly in the ipsilateral LP, the rostral portion of the pontine nuclei and the superficial layers of the ipsilateral superior colliculus which corresponds to the representation of the central visual field. Less dense labeled terminals were also found in the ipsilateral nucleus of the optic tract (NOT) in two cats.