Kendra K. Noneman^1,2, Emily Lopez^1,2, Matthew A. Smith¹, J. Patrick Mayo²; ¹Carnegie Mellon University, ²University of Pittsburgh

Natural visual behavior depends on transforming incoming visual information into coordinated eye movement commands. To track unpredictably moving objects, primates alternate between fast, discrete saccades and slower, continuous smooth pursuit—underscoring the tight coupling between these two sensorimotor systems to support seamless gaze control. However, these eye movement sub-types have largely been studied independently and are often thought to be driven by distinct regions of the frontal eye fields (FEF). FEF contains saccade-responsive neurons that respond to visual stimuli or the (saccadic) movement. The distinction between sensory and motor responses for pursuit-responsive neurons is less clear because pursuit depends on the rapid interaction of both to continuously track a moving visual target. In this study, we examined how saccades and pursuit are represented at the level of single neurons and neural populations in the macaque FEF by simultaneously recording activity from neurons with diverse response properties. We classified neurons according to their responsiveness along: 1) a saccade-pursuit continuum, and 2) a more conventional visual-motor (saccadic) continuum during a memory-guided saccade task. Most FEF neurons responded to both saccades and pursuit rather than exclusively to one type of eye movement. At the population level, correlated variability was higher for neuron pairs with similar saccade–pursuit or visual–motor selectivity compared with pairs that were more dissimilar. Our findings show that saccade and pursuit representations overlap more than previously thought, providing new insight into how FEF coordinates flexible visuomotor transformations.

Acknowledgements: Whitehall Foundation, R01EY035673, P30EY008098, T32EY017271