Modulation of inhibitory communication coordinates looking and reaching

Looking and reaching are controlled by different brain regions and coordinated during natural behaviour1-3. Understanding how flexible, natural behaviours like coordinated looking-and-reaching are controlled depends on understanding how neurons in different regions of the brain communicate4. Excitatory multiregional communication recruits neural coherence in a gamma-frequency (40-90 Hz) band5. Inhibitory control mechanisms are also required to flexibly control behaviour6, but little is known about how neurons in one region transiently suppress individual neurons in another to support behaviour. How does neuronal firing in a sender-region transiently suppress firing in a receiver-region? Here, we study inhibitory communication during a flexible, natural behaviour, termed gaze-anchoring, in which saccades are transiently inhibited by coordinated reaches. During gaze-anchoring, we find that neurons in the reach region of the posterior parietal cortex can inhibit neuronal firing in the parietal saccade region to suppress eye movements and improve reach accuracy. Importantly, suppression is transient, only present around the coordinated reach, and greatest when reach neurons fire spikes at a particular phase of beta-frequency (15-25 Hz) activity, not gamma-frequency activity. Our work provides evidence in the activity of single neurons for a novel mechanism of inhibitory communication in which beta-frequency neural coherence transiently inhibits multiregional communication to flexibly coordinate our natural behaviour.