Why sensory neurons are tuned to multiple stimulus features

Many sensory neurons encode information about more than one stimulus feature. Multidimensional tuning increases ambiguity in stimulus-response relationships, but we find that it also offers an unexpected computational advantage, allowing the brain to better reconstruct sensory stimuli. From the responses of sensory neurons, populations, and sensory-driven movement behavior, more information can be recovered about a stimulus vector than about its individual components. We term this coding advantage "stimulus synergy" and show that it is distinct from other coding synergies, arising from inseparability of the response-conditioned stimulus distribution along individual stimulus dimensions. From extracellular recordings in motion sensitive cortex and measurements of pursuit eye movements, we demonstrate that stimulus synergy in cortical populations is preserved downstream in the precision of pursuit, and that a common decoding model predicts the level of synergy in pursuit behavior. This suggests that the brain exploits the information advantage afforded by multidimensional sensory tuning.