Alpha-Theta Correlations during the Different States of the Brain for a Designed Cognitive Task

Abstract

Brain oscillations vary due to neurological activities that play an important role in designing a cognitive task. In the proposed study, 27 subjects experimented with different cognitive activities (rest, meditation, and arithmetic) and their alpha and theta bands of frequencies were analyzed. BIOPAC-MP-160 has performed the data acquisition and further processing of the acquired dataset was implemented in EEGLAB. The results illustrated that the cross-frequency correlation (alpha: theta: 1:2) between alpha and theta waves has been enhanced during effortful cognition (arithmetic state). The alpha-theta cross-frequencies were observed to be maximum in the arithmetic state, while it remains low in both the resting and meditation states. Maximum episodes of the cross-frequency correlations occurred when the alpha band of frequencies lies between 9-12 Hz. The study also reveals that maximum alpha-theta cross-frequency (40.74%) was found at the electrode positions Af3 and Af4. The comparisons based on event-related potentials (ERPs) and power spectral densities (PSDs) have shown that the meditation state is more sluggish than the arithmetic and rest states.