Stable 3D Head Direction Signals in the Primary Visual Cortex

The mammalian brain9s navigation system is informed in large part by visual signals. While the primary visual cortex (V1) is extensively interconnected with brain areas involved in computing head direction (HD) information, it is unknown to what extent navigation information is available in the population activity of visual cortex. To test whether information about head direction information is available in visual cortex, we recorded neuronal activity in V1 of freely behaving rats. We show that significant information about yaw, roll, and pitch of the head can be linearly decoded from V1 either in the presence or absence of visual cues. Individual V1 neurons were tuned to head direction, with a quarter of the neurons tuned to conjunctions of angles in all three planes. These results demonstrate the presence of a critical navigational signal in a primary cortical sensory area and support predictive coding theories of brain function.