Temporal and spatial frequency tuning of the flicker motion aftereffect

The motion aftereffect (MAE) was used to study the temporal and spatial frequency selectivity of the visual system at supra-threshold contrasts, Observers adapted to drifting sine-wave gratings of a range of spatial and temporal frequencies. The magnitude of the MAE induced by the adaptation was measured with counterphasing test gratings of a variety of spatial and temporal frequencies, Independently of the spatial or temporal frequency of the adapting grating, the largest MAE was found with slowly counterphasing test gratings (at approximately 0.125-0.25 Hz). The largest MAEs were also found when the test grating was of similar spatial frequency to that of the adapting grating, even at very low spatial frequencies (0.125 c/deg), These data suggest that MAEs are dominated by a single, low-pass temporal frequency mechanism and by a series of band-pass spatial frequency mechanisms, The band-pass spatial frequency tuning even at low spatial frequencies suggests that the ''lowest adaptable channel'' concept [Cameron et al. (1992). Vision Research, 32, 561-568) may be an artifact of disadvantaged low spatial frequencies using static test patterns. Copyright (C) 1996 Elsevier Science Ltd.