Results presented earlier showed that the task reference θ power did not differ across stimulus types. Therefore, use of the average reference θ power across the three stimulus types as representative of the pre-stimulus θ power throughout the task is justified. The top row of Figure 3 shows group comparisons of the grand average power spectra at electrode site FCz for the task (left plot of top row) and the resting condition (right plot of top row). The reference θ power (left plot of top row) across the selected θ band (4 Hz – 6 Hz) shows that, on average, the reference θ power is larger in the NACs compared to the LTAA, as presented in section (iii) of the results. The grand average resting power spectra (right plot of top row) also show that, on average, the power across the selected θ band is larger in the NACs compared to the LTAAs.
