Pattern adaptation is one of the fundamental sensory processes in the visual system. In this study, we compared pattern adaptation induced by two types of sinu-soidal drifting grating in dLGN cells of cat. The two types of grating have the same parameters (e.g. spatial frequency, temporal frequency and contrast) except their pattern shapes, one of which is normal grating and the other annular grating. The results suggested that the annular grating elic-ited stronger response and stronger pattern adaptation than the normal grating. This is consistent with the adaptation and aftereffect to the two types of drifting gratings seen in psychology and may reflect the subcortical neural mecha-nism underlying these psychological phenomena.
