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D. J. Quinlan, J. C. Culham; Flicker motion aftereffect produces fMRI activation in MT. Journal of Vision 2001;1(3):241. doi: 10.1167/1.3.241.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Motion area MT+ shows enhanced activity during the perception of the motion aftereffect (MAE) when static test stimuli are used (static MAE; Tootell et al., 1995, Nature). MAEs can also be observed with flickering test stimuli (flicker MAE) and psychophysical evidence suggests potentially different neural substrates than the static MAE. We used functional magnetic resonance imaging (fMRI) to examine neural activity during the flicker MAE. Methods: Using a 4 Tesla fMRI, we first identified MT+ using a motion localizer and then measured MT+ activity during the flicker MAE. Six subjects viewed an adapting grating that either rotated continuously (MAE condition) or reversed direction every 2 sec (Control condition) for 24 sec. Subsequently, a radial counterphase flickering test grating was presented for 21 sec and the duration of the resulting aftereffect was measured. Following continuous motion adaptation, subjects perceived the flickering test pattern as moving in the opposite direction; whereas, following the control condition, no MAE was perceived. Results: When the test grating was presented, activity in MT+ remained elevated for a longer period in the MAE condition than the control condition. Conclusions: During the flicker MAE, like the static MAE, activity in MT+ is correlated with the illusory motion percept. Future research will address the contribution of attention.
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