Title: Neural activation of auditory cortices during rhythmic behavior in macaques

Abstract: Sensory-guided rhythmic behaviors require to compare movement-related signals with the ongoing sensory flow from moment to moment. Here, we aim to understand the activation dynamics of the auditory cortex during sensorimotor synchronization in the scale of the hundreds of milliseconds (550-850 ms). To do this, we trained two rhesus macaques to perceive and then synchronize their hand movements to auditory metronomes that vary in their inter-sound interval on a trial-by-trial basis. Extracellular activity was recorded in the core and belt auditory areas using silicon linear probes. First, macaques were able to predictively entrain to the auditory metronomes performing anticipatory movements to the ongoing sensory events. Second, we observed segregable activation profiles in both auditory cortical regions during sensation, perception and behaving conditions. The temporal structure of the metronomes was represented as phasic and short-duration power enhancements across frequency bands (0.5-140 Hz) during the passive listening and mainly in the supra- and granular layers. This feedforward sensory-driven activation profile switched to bursts of power enhancement and suppression in the delta, theta and betta bands during the synchronization but not perception phase. These frequency bands exhibited an oscillatory and buildup enhancement mainly in the infragranular layers. Second, segregable groups of neurons exhibited shorter latencies and less variable activation to sensory or motor events in both core and belt areas. Remarkably, we identified auditory cortical neurons that were active only during the synchronization phase with a buildup activation profile across the serial order of the metronome. Finally, the unexpected omission of sounds within the metronome elicited a change in both directions, i.e., increase and decrease in the firing activity of different set of neurons. The results reveal strong feedback behavior-related signals dynamically and differentially change LFP oscillations, set of neurons and layers as the animals entrain their movements to the regularity of the auditory sequences. Our study contributes to probe sensorimotor neural circuits that support closed-loop and continuous behaviors.