Behavioral states affect eye position tuning in the parietal cortex of macaques

Posterior parietal neural populations compute flexible yet stable representations of spatial locations using eye position information, and plan effector movements across various goal-directed contexts. How space is represented during internally driven non-goal-directed behaviors and whether these spatial representations are affected by the different behavioral contexts and the underlying brain states remain understudied. We compared eye position signals in single neurons in macaque parietal cortex (area V6A) during constrained fixations toward visual targets with gaze activity during self-paced fixations in darkness. While the firing rates of V6A neurons were comparable in the two conditions, the spatial tuning of gaze activity was stronger during the spontaneous fixations than during task-constrained fixations. Moreover, neural responses were more variable in constrained fixation. Our results confirm the flexibility of spatial representations in parietal cortex and indicate that eye position signals provide spatial information in a wider range of behavioral contexts beyond visual and visuomotor processing.