Visual receptive-field characteristics of posterior thalamic and pretectal neurons in the rabbit

Abstract

Receptive fields were determined for 309 cells recorded from the posterior thalamus of 42 Dutch belted rabbits. The responses of the cells to visual stimulation were classified according to receptive field configuration and trigger features as being one of several types: (1) oriented direction-selective, (2) oriented, (3) concentric, (4) direction-selective, (5) movement-sensitive, (6) uniform, (7) diffuse, or (8) no response. Neurons located within nuclei or portions of nuclei which receive a direct projection from the retina (lateral geniculate, dorsal layers of the superior colliculus, dorsal portion of the posterior thalamic nucleus, and dorsal portion of the pretectal nucleus) had highly specific receptive field characteristics, i.e. , the first 5 types. Neurons located within areas which do not receive direct retinal projections, but do not receive visual projections from the superior colliculus and visual cortex (ventral layers of the superior colliculus, ventral portion of the posterior thalamic nucleus, ventral portion of the pretectal nucleus, lateral posterior nucleus, and dorsal medial geniculate nucleus) had much less selective receptive fields, i.e. , the last 3 types. Neurons in regions receiving only indirect visual projections showed rapid adaptation or habituation to repeated sensory stimulation, while those located in the direct retinal pathway did not. Responses to auditory or somatosensory stimulation were recorded from cells in the indirect visual areas only.