Comparison of tripolar and traditional EEG recording of the visual evoked potential.

Scalp-recorded electroencephalography (EEG) is an effective method to quantify brain activity because it is noninvasive and has high temporal resolution. Even so, EEG is highly susceptible to physiological and non-physiological noise. Tripolar concentric ring electrodes (TCREs) provide an EEG measure (tEEG) designed to be robust to extraneous sources of noise. Previous studies have demonstrated this benefit in settings of high physiological noise such as muscle-related potentials and seizure detection. However, less has been done to study the efficacy of this technology in visual neuroscience. This study compares the noise profiles of traditional EEG and tEEG as well as the morphology of the pattern-reversal visual evoked potential recorded simultaneously using tEEG and emulated traditional EEG techniques. Our results indicate the two approaches have qualitatively similar noise profiles with the tEEG being significantly more robust to line noise (i.e. 60 Hz and its harmonics). In addition, while the overall morphology of the evoked potentials are similar, systematic differences in the latencies of the primary peaks of the waveforms indicate the two approaches do not detect exactly the same signal. Arising from the distinct electrode configuration of the TCRE, we hypothesize that the observed differences reflect the spatiotemporal geometry of the underlying neural responses to the pattern-reversing stimulus. Taken together, the results of this study suggest that tEEG is well suited to the study of human visual processing and offers both increased robustness to non-physiological sources of noise and a new opportunity to study the spatiotemporal dynamics of visual processing in the human brain.