Critical flicker frequency responses in visual cortex

Critical flicker frequency (CFF) threshold is defined as the frequency at w hich a flickering light is indistinguishable from a steady, non-flickering light. CFF is useful for assessing the temporal characteristics of the visu al system. While CFF responses are believed to reflect activity in the cent ral visual system, little is known about how these temporal frequencies are processed in the visual cortex. The current paper estimated the CFF thresh old for cells in the rat visual cortex by recording single unit responses t o flickering stimuli. Results showed that: (1) there was a broad range of t emporal tuning, (2) CFF threshold was lower in simple cells than in complex and hypercomplex cells, and (3) there was no significant difference in CFF threshold between areas 17 and 18.