Characterisation of EEG Activity in Stimulation and Rest Periods by Analysis of Steady-State Visual Evoked Potentials

In this study, the brain response was investigated using steady-state visual evoked potentials (SSVEP) on recordings of electroencephalographic (EEG) activity during periods of stimulation and rest. The motivation for this work was to understand how the presence of an intermittent visual stimulus manifests itself in brain activity. The main objective was to quantitatively differentiate between stimulation and resting states by analysing the energy detected during stimulation pulses. An experimental protocol was employed in which subjects were exposed to a flashing light at 15 Hz for 7 s, followed by an interval of 4 s without stimulation, repeating this cycle for 10 min. By analysing the power spectrum of the EEG recordings using the spectrogram method, the average energy detected during the stimulation and rest periods was calculated. The results indicated that the energy detected during stimulation periods was significantly higher compared to rest periods. This suggests that SSVEPs represent a reliable response for distinguishing between stimulation and resting states in EEG recordings. These findings support the utility of SSVEP as biomarkers of brain activity during intermittent visual stimulation. In turn, a detailed characterisation of brain activity during periods of stimulation and rest has been achieved by analysing these potentials. These results contribute to the knowledge about the brain response to intermittent visual stimuli and may have multiple applications in the field of neuroscience and clinical research.