Dynamics of the alpha peak frequency during flicker stimulation

Repetitive visual stimulation elicits specific brain responses known as steady state visual evoked potentials (SSVEP). The SSVEP manifests as oscillatory components at the stimulation frequency or harmonics in brain signals such as the electroencephalogram(EEG) or magnetoencephalogram. Analysis of the dynamics of the SSVEP permits to characterize the neurophysiological basis of visual processing. Classical SSVEP analysis is restricted to the study of the EEG power at the stimulation frequency. In this paper, we focus on the dynamics of the alpha peak frequency under flicker stimulation. The alpha peak frequency is person specific and plays an important role on mental load. High resolution time-frequency methods are necessary to precisely identify the alpha peak frequency. We utilize therefore matching pursuit methods using stochastic dictionaries. We show that the alpha peak frequency decreases during flicker stimulation. We argue that this phenomenon can partially explain the relative fast habituation of the SSVEP, i.e. the strength of the SSVEP decreases after few seconds of continuous flicker stimulation.