Unit responses in the frog's caudal thalamus.

Single unit microelectrode recordings were made in the caudal thalamic region of the frog, Rana pipiens, from a sample of multimodal sensory units which included monocular, binocular, tactile, and spontaneous types, and which showed a wide variety of receptive field sizes, response rates, preferred stimulus sizes habituation rates, and velocity and tactile sensitivities. A number of special response properties were occasionally observed, including directional sensitivity, stationary object sensitivity, afterdischarges, and visual and tactile inhibitory fields. Computer analysis of spontaneously active units revealed four types: regular, exponential, bursting, and multimodal.