Precision timing with α-β oscillatory coupling: stopwatch or motor control?

Abstract Precise timing is crucial for many behaviors ranging from street crossing, conversational speech, to athletic performance. The precision of motor timing has been suggested to result from the strength of phase-amplitude coupling (PAC) between the phase of alpha oscillations (α, 8-12 Hz) and the power of beta activity (β, 14-30 Hz), herein referred to as α-β PAC. The amplitude of β oscillations has been proposed to code for temporally relevant information, and the locking of β power to the phase of α oscillations to maintain timing precision. Motor timing precision has at least two sources of variability: variability of timekeeping mechanism and variability of motor control. There is ambiguity to with of these two factors α-β PAC could be ascribed to. Whether α-β PAC indexes precision of internal timekeeping mechanisms like a stopwatch, or α-β PAC indexes motor control precision is unclear. To disentangle these two hypotheses, we tested how oscillatory coupling at different stages of time reproduction related to temporal precision. Human participants perceived, and subsequently reproduced, a time interval while magnetoencephalography was recorded. The data show a robust α-β PAC during both the encoding and the reproduction of a temporal interval, a pattern which could not be predicted for by the motor control account. Specifically, we found that timing precision resulted from the tradeoff between the strength of α-β PAC during the encoding and during the reproduction of intervals. We interpret these results as supporting evidence for the hypothesis that α-β PAC codes for precision of temporal representations in the human brain. Highlights - Encoding and reproducing temporal intervals implicate α-β PAC. - α-β PAC does not represent solely motor control. - α-β PAC maintains the precision of temporal representations.