The compositional encoding of hand-eye coordinated movements for single neurons in the posterior parietal cortex.

Seventy-nine percent of posterior parietal cortex (PPC) neurons in a single human participant show additively separable hand- and eye-movement tuning during a center-out hand-eye task.

• Why it matters: The neural mechanism for hand-eye coordination is unclear, especially whether PPC represents hand and eye signals independently or as tightly coupled codes.
• What they did: Across 11 sessions, 412 single neurons were recorded from motor cortex (MC; n = 251) and PPC (n = 161) while the participant performed a center-out H-E coordinated task.
• The result: Compositional decoders trained on single-effector movements matched coordinated decoders in PPC (hand: 66% vs. 69%; eye: 34% vs. 36%), while MC neurons showed negligible eye modulation.