[2- 14C]deoxyglucose uptake in rat visual system during flashing-diffuse and flashing-pattern stimulation over a 6 log range of luminance.
The 2-deoxyglucose autoradiographic technique was used to assess the metabolic activity of cortical area 17, the dorsal and ventral lateral geniculate nuclei, the lateral posterior nucleus, and the superior colliculus, during 5-Hz flashing-pattern (montage of black and white square-wave gratings) and flashing-diffuse (eye covered with white mask) stimulation at three intensities over a 6 log range. In area 17 flashing-pattern was found to be equally effective at elevating uptake of the functional label over the photopic-scotopic range of luminance levels tested, whereas flashing-diffuse was ineffective. In subcortical nuclei, however, flashing-diffuse was no less effective than flashing-pattern and uptake of the label correlated positively with intensity level. The results suggest that the subcortical components of the visual system do play an important role in the processing of intensity information and that primary visual cortex does not.