Sound unmasks short-latency tectal visual signals that are independent of the primary visual cortex

Optimal behavior requires active coordination between exogenous sensory events and internal brain states. Understanding such coordination is rendered challenging given the massive parallelism, followed by equally massive convergence, of sensory signals, even within a single sensory modality, when conveying information to the motor periphery. Here, using audiovisual stimulation and saccadic orienting, we show how multisensory stimulation differentially recruits visual processing pathways bypassing the primary visual cortex (V1), which may otherwise appear dormant. We reversibly inactivated primate V1 and explored the influences on short-latency reflexive saccadic resetting. Having recently shown that such resetting is eliminated by V1 inactivation, randomly interleaving task-irrelevant simultaneous sounds not only recovered the phenomenon, but it was also associated with V1-independent neuronal modulations in both the superior (SC) and inferior (IC) colliculi. These results show that even when the geniculostriate pathway is dominant, like in primates, alternative visual pathways still alter behavior under the right sensory contingencies.