CFF task and peak alpha frequency
We found no correlation between thresholds obtained with the CFF task and peak alpha frequency from eyes-closed EEG recording. This result illustrates how the choice of behavioural task may influence the results obtained in brain rhythmicity studies. As already touched upon by Buergers & Noppeney (2022), the effect alpha frequency may have on temporal perception may be very small and brittle, and may only be apparent for very specific stimulus parameters. A lack of correlation between the CFF task and peak alpha frequency may also be due to the continuous nature of the task stimulus, which may force alpha oscillations out of their natural rhythms; a phenomenon that is often intentionally induced in Steady State Visually Evoked Potential (SSVEP) research (Regan, 1966; Norcia et al., 2015). Alpha power is also expected to reduce greatly during perception of a continuous stimulus, which in turn might affect alpha frequency as well, as the two are found to be intrinsically linked (Nelli et al., 2017). Additionally, previous literature has suggested that peak alpha frequency may only be indicative of perceptual sensitivity when the stimulus last for less than one alpha cycle (Keitel et al., 2022, Michail et al., 2022).