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Stable 3D Head Direction Signals in the Primary Visual Cortex

Visual signals influence the brain’s computation of spatial position and orientation. Accordingly, the primary visual cortex (V1) is extensively interconnected with areas involved in computing head direction (HD) information. Predictive coding theories posit that higher cortical areas send sensory or motor predictions to lower areas, but whether this includes cognitive variables like the HD signal—and whether HD information is present in V1—is unknown. Here we show that V1 encodes the yaw, roll, and pitch of the head in freely behaving rats, either in the presence or absence of visual cues. HD tuning was modulated by lighting and movement state, but was stable on a population level for over a week. These results demonstrate the presence of a critical spatial orientation signal in a primary cortical sensory area and support predictive coding theories of brain function.