The relationship between the visual evoked potential and the gamma band investigated by blind and semi-blind methods.
Bottom Line: FSS was performed with both temporal and spectral constraints to identify specifically the generators of the main peak of the VEP (P100) and of the GBA.Analysis of the VEP extracted using the different methods demonstrated very similar morphology and localisation of the generators.The results suggest that the VEP and GBA may be generated by the same neuronal populations, and implicate this relationship as a potential mediator of the correlation between the VEP and the Blood Oxygenation Level Dependent (BOLD) effect measured with fMRI.
Affiliation: Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle upon Tyne, UK. firstname.lastname@example.orgShow MeSH
Related in: MedlinePlus
Mentions: To emphasize these effects, Fig. 7 shows the upper and lower quartiles of the data presented in columns 2 and 3 of Fig. 6 for the regressed data (i.e., the 25% of trials with the highest VEP/P100 area, and the 25% of trials with the lowest VEP/P100 area). In Fig. 7, when the evoked component was regressed out, higher power in alpha, beta and low/high gamma band can be seen for the fourth quartile with respect to the first quartile when we ordered by the VEP (Fig. 7 upper half), with respect to the P100 (Fig. 7 lower half). Fig. 7 also demonstrates more clearly that these effects were more evident when ordering by the VEP area than by the P100 area, suggesting a link specifically between VEP area and spectral power in the alpha, beta and gamma bands. Note that as the data in Fig. 7 were baseline corrected in the interval − 100 ms to 0 ms, the positive and negative deviations are variations about the mean. In particular for the alpha band, there is a prolonged desynchronisation that is evident throughout the stimulus period (see Figs. 3 and 4) which then becomes the baseline for the single trial analysis of Fig. 7. Superimposed on these sustained effects are transient peaks associated with the checkerboard reversal. These reversal-related alterations in the frequency content of the EEG can most clearly be seen in Fig. 4, and are present for all of the frequency bands examined. Fig. 7 therefore suggests that trials with a low VEP amplitude have proportionately more alpha desynchronisation than trials with a high VEP.
Affiliation: Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle upon Tyne, UK. email@example.com