The visual system of the mouse offers the opportunity for the use of genetic approaches to an understanding of central nervous system development, function, and pathology. The mouse visual system has many features in common with that of the human and other higher mammals. The present proposal in response to RFA MH-99-006 is for the development, verification, and dissemination of procedures for a quantitative, rapid and reliable assessment of visual function in the mouse that would be sensitive to abnormalities from the level of the optic media and retina up to and including the level of the primary visual cortex. Swept visual evoked potentials recorded over the visual cortex will be used to define the visibility of grating stimuli of a range of contrasts and spatial frequencies. Signal-to-noise ratios in normal mice are sufficiently large to allow reliable measurement of vision through one eye in 240 sec of data collection, consistent with a goal of screening vision through both eyes at a rate of 4 mice/hour. This proposal represents a collaboration between a laboratory that has over the past several years delineated mechanisms of activity-dependent plasticity in the mouse primary visual cortex, along with genetic disturbances in those mechanisms, and one that perfected the swept VEP and distributed it widely for uses including the screening of visual development in human infants. These assays should permit the investigation of the genetic bases of visual system development and function at levels from the eye to the cortex.