III-67. A recurrent neural network that produces EMG from rhythmic dynamics

from a macaque during free viewing of natural images. To measure the neurons’ tuning to features of the stimulus in this context, we used Gabor-filter ‘energy’ models, modified such that the degree of stimulus tuning (‘response gain’) was a function of time since fixation onset. We also fit similar models to the LFP power in different frequency bands to describe the stimulus-evoked network activity. We found that, in addition to evoking a large, transient response in the spiking activity and LFP, saccades entrained ~10 Hz alpha oscillations in the LFP that persisted throughout the subsequent fixation. By transforming to time coordinates of alpha cycles, we found that these alpha oscillations modulated the response gain of V1 neurons, resulting in a temporal windowing of the stimulus processing following saccades. The stimulus tuning of gamma (35-60 Hz) power was similarly modulated by the alpha rhythm, and the gamma oscillations provided further temporal structure to the spiking activity through spike-phase coupling. These results show that during free viewing, alpha oscillations following saccades create a temporal windowing of V1 activity during fixations, and more generally suggest that stimulus-driven network dynamics may play an important role in shaping feedforward stimulus processing.