- If one accepts the notion of an internal clock, then one must further presume that time production is attuned with the rate of functioning of the clock's pacemaker. We look at the individual's online EEG recording while performing a time-production task, placing one focus of interest on the individual's peak alpha frequency (PAF), and a s econd on alpha power and its topography. The participants completed a time- production task with online EEG recording, twice during a single session in the lab, in a pre-post design. We present data concerned with the topography of post-pre differences in a lpha power, both during time production and during rest, as a function of an intervening period of either restful wakefulness or motor activity. Our major finding is that left PAF and right PAF mutually suppress each other in predicting produced duration, and that given the size and sign of their regression weights, it is a left-right asymmetry in PAF that plays a pivotal role here. On computing a left-right asymmetry index for PAF, we found that this index had a significant correlation with the mean log- transformed produced duration ( r = .364, p < .01), and that the relationship is stronger among females (r = .500, p < .005).