Joint Representation of Translational and Rotational Components of Self-Motion in the Parietal Cortex

Navigating through the world involves processing complex visual inputs to extract information about self-motion relative to one\u27s surroundings. When translations (T) and rotations (R) are present together, the velocity patterns projected onto the retina (optic flow) are a combination of the two. Since navigational tasks can be extremely varied, such as deciphering heading or tracking moving prey or estimating one\u27s motion trajectory, it is imperative that the visual system represent both the T and R components. Despite the importance of such joint representations, most previous studies have only focused on the representation of translations. Moreover, these studies emphasized the role of extra-retinal cues (efference copies of self-generated rotations) rather than visual cues for decomposing the optic flow. We recorded single units in the macaque ventral intraparietal area (VIP) to understand the role of visual cues in decomposing optic flow and jointly representing both the T and R components. Through the following studies, we establish that the visual system can rely on purely visual cues to derive the translational and rotational components of self-motion. We also show for the first time, joint representation of T and R at the level of single neurons