Abstract
A prominent feature of sensory processing is the ability to distinguish whether the activation of the sensory periphery is caused by changes in the external world or by the animal’s own actions1. Saccades, rapid eye movements executed by animals across phyla2–4, cause the visual scene to momentarily shift on the retina. The mechanisms by which visual systems differentiate between motion of the visual scene induced by saccades from motion due to changes in the external world are not fully understood. Here, we discovered that in mouse primary visual cortex (V1), the two types of motion evoke distinct patterns of activity across the population of neurons. As a result, a decoder of motion direction trained on the response to motion in the external world fails to generalize when tested on the response to saccades that induce similar motion on the retina. This is because during saccades, V1 combines the visual input with a strong non-visual input arriving from the pulvinar nucleus of the thalamus. This non-visual input is an efference copy – a copy of the oculomotor command that differs depending on the direction of the saccades. Silencing the pulvinar prevented the non-visual input from reaching V1, such that the pattern of activity in V1 was now similar no matter whether the motion was generated in the external world or by saccades. Thus, the pulvinar input to V1 ensures differential responses to the external and self-generated motion and may prevent downstream areas from extracting motion information about visual stimulus shifts generated by saccades. Changing the pattern of evoked activity through an efference copy may be a general mechanism that enables sensory cortices in mammals to distinguish between external and self-generated stimuli.
Competing Interest Statement
The authors have declared no competing interest.
