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).