We studied the responses to sensory stimulation in two diencephalic areas, the central posterior nucleus of the dorsal thalamus (CP) and the anterior tuberal nucleus of the hypothalamus (TA). In both the CP and the TA, units sensitive to acoustic (500-Hz sound), hydrodynamic (25-Hz dipole stimulus), and visual (640-nm light flash) stimuli were found. In the CP, most units were unimodal and responded exclusively to visual stimulation. In contrast, in the TA, most units responded to more than one modality. The data suggest that the CP is primarily involved in the unimodal processing of sensory information, whereas the TA may be involved in multisensory integration.