Temporal Modulation of Steady-State Visual Evoked Potentials

• Published in: International journal of neural systems Vol. 29; no. 3; p. 1850050
• Main Authors: Labecki, Maciej, Nowicka, Maria Malgorzata, Suffczynski, Piotr
• Format: Journal Article
• Language: English
• Published: Singapore 01.04.2019
• Subjects: time evolution; SSVEP; harmonics; flicker stimulation; habituation
• ISSN: 1793-6462
• DOI: 10.1142/S0129065718500508

Electroencephalographic responses to periodic stimulation are termed steady-state visual evoked potentials (SSVEP). Their characteristics in terms of amplitude, frequency and phase are commonly assumed to be stationary. In this work, we tested this assumption in 30 healthy participants submitted to 50 trials of 60 s flicker stimulation at 15 Hz frequency. We showed that the amplitude of the first and second harmonic frequency components of SSVEP signals were in general not stable over time. The power (squared amplitude) of the fundamental component was stationary only in 30% the subjects, while the power at the second harmonic frequency was stationary in 66.7% of the group. The phases of both SSVEP frequency components were more stable over time, but could exhibit small drifts. The observed temporal changes were heterogeneous across the subjects, implying that averaging results over participants should be performed carefully. These results may contribute to improved design and analysis of experiments employing prolonged visual stimulation. Our findings offer a novel characterization of the temporal changes of SSVEP that may help to identify their physiological basis.