Joint representation of translational and rotational components of optic flow in parietal cortex

Significance As we navigate through the world, we experience both translations (changes in position) and rotations (changes in orientation). Although several studies have examined how the visual system represents the translational component of self-motion, few have evaluated the neural representation of rotations, especially when translations and rotations occur simultaneously. We measured responses of neurons in parietal cortex to visually simulated combinations of translations and rotations. We find that many parietal neurons jointly encode the translational and rotational components of self-motion in a multiplicatively separable fashion, which simplifies perceptual estimation of both components. These results suggest that the brain performs sophisticated processing of visual motion to extract both translation direction and rotation velocity, such that we may perform complex navigational tasks.