Modulation of Neuronal Activity and Saccades at Theta Rhythm During Visual Search in Non-human Primates
Jin Xie1,2 • Ting Yan1 • Jie Zhang1,2,3 • Zhengyu Ma3 • Huihui Zhou1,31 The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain ScienceShenzhen Fundamental Research Institutions, Shenzhen 518055, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 The Research Center for Artificial Intelligence, Peng Cheng Laboratory, Shenzhen 518000, China
Abstract
Active exploratory behaviors have often been associated with theta oscillations in rodents, while theta oscillations during active exploration in non-human primates are still not well understood. We recorded neural activities in the frontal eye field (FEF) and V4 simultaneously when monkeys performed a free-gaze visual search task. Saccades were strongly phase-locked to theta oscillations of V4 and FEF local field potentials, and the phase-locking was dependent on saccade direction. The spiking probability of V4 and FEF units was significantly modulated by the theta phase in addition to the time-locked modulation associated with the evoked response. V4 and FEF units showed significantly stronger responses following saccades initiated at their preferred phases. Granger causality and ridge regression analysis showed modulatory effects of theta oscillations on saccade timing. Together, our study suggests phase-locking of saccades to the theta modulation of neural activity in visual and oculomotor cortical areas, in addition to the theta phase locking caused by saccade-triggered responses.
Keywords
Visual search; Saccade; Theta rhythm; FEF; V4; Non-human primate
