Abstract
Recent advances in large scale electrophysiological and optical recording techniques have revealed that intrinsic fluctuations in cortical activity exhibit organized spatiotemporal structure, often in a form well characterized as traveling waves. While intrinsic traveling waves (iTWs) had often been studied during states of anesthesia, sleep, or low arousal, we find that iTWs occur during normal activity in the visual cortex of the alert non-human primate. iTWs occur multiple times per second and modulate the magnitude of sensory evoked activity in a phase-dependent manner. Further, we have shown that the state of iTWs impact visual perception in marmosets as they perform a challenging visual detection task. We have constructed a large-scale conductance-based topographic spiking network model that recapitulates the phenomenology of iTWs in vivo. The model shows that large-scale iTWs emerge from propagation delays in locally asynchronous spiking dynamics throughout cortical horizontal fiber networks. The model predicts that neuronal activity during iTWs is sparse, in the sense that only a small fraction of the neural population participates in any individual iTW. As a result, iTWs can occur without inducing correlated variability, which has been shown to impair sensory discrimination. The model also predicts that iTWs traverse feature domains through the horizontal fibers that connect similarly-tuned cortical columns and are coordinated across visual cortical areas via the retinotopically ordered interareal projections. We find preliminary evidence supporting these predictions from electrophysiological recordings in vivo. Taken together, these findings lead to the conclusion that feature-selective and retinotopically-ordered projection systems endow the visual system with the capacity to organize intrinsic spiking activity into iTWs to improve perception.