Geyu Weng^1,2, Behrad Noudoost², Neda Nategh^2,3; ¹Department of Biomedical Engineering, University of Utah, ²Department of Ophthalmology and Visual Sciences, University of Utah, ³Department of Electrical and Computer Engineering, University of Utah

The brain generates a perception of visual space through processing and interpreting the location of stimuli projected onto the retina, yet how spatial information is represented and read out in neural responses remains unclear. To understand the brain’s spatial code, it is essential to investigate alterations in neural activity that accompany changes in visual perception. In this study, we measure location perception in rhesus macaque monkeys using combined behavioral and physiological experiments, linking perisaccadic modulations in extrastriate responses to their behavioral counterparts. We use array and single electrodes to simultaneously record spiking activity and local field potentials (LFPs) in area V4 and the Frontal Eye Field (FEF) from sites with overlapping receptive fields while the monkey’s eye movements are monitored. In each trial, the monkey makes a saccade from a fixation point to a peripheral saccade target. During fixation and saccade execution, a 50-ms visual probe stimulus is presented in one of nine possible locations in a 3×3 grid placed around the V4 neuron's receptive field. When the probe disappears, the monkey makes another saccade to the perceived stimulus location. We measure perisaccadic mislocalization, defined as the shift in the perceived location of a stimulus when presented around the time of the first saccade, compared to when it is presented during fixation. We correlated mislocalization magnitudes with spike rates in populations of FEF and V4 neurons and showed that trials associated with the smaller magnitudes of mislocalization corresponded to higher firing rates in these areas. We then analyzed FEF and V4 signals, recorded simultaneously during the same session, to extract the oscillatory components communicated between the two areas around the time of saccades. We show that behavioral mislocalization can be traced in FEF and V4 signals, demonstrating the possible role of prefrontal and extrastriate areas in location perception.