Transient focal inactivation of the primary visual cortex abolishes saccadic inhibition

Abstract

Most organisms are perpetually engaged in an active-perception cycle: at any moment, planning, executing, or recovering from a given own movement. In the oculomotor system, such a cycle is under a powerful, reflexive, and short-latency interruptive influence by exogenous sensory stimulation, but the multitude of possible pathways eventually converging on the final oculomotor control gateway make it unknown how reflexive oculomotor inhibition takes place. Here we show that transient focal inactivation of the primary visual cortex abolishes visually-driven saccadic inhibition, suggesting an unequivocal dominance of the geniculostriate visual pathway over this robust behavioral reflex. Using chronic lesions, computational modeling, and fine-grained eye-movement analyses, we then show that latent visual signals bypassing the geniculostriate pathway are still present, but may not be as central as previously anticipated. These results recast classic views on visual-motor reflexes, and motivate functional and theoretical investigations of the multiplicity of parallel input-output loops in the brain.