The enhancement in the ERS is opposite in direction to the reduction in P3b amplitude in LTAAs compared to NACs (or equivalently, to the reduction in evoked δ and θ power, which comprise the P3b waveform (Andrew and Fein, In Press)). The spatial localization of induced θ oscillations over fronto-central regions also differs to that of the evoked δ and θ power measures, which show spatial localization over the centro-parietal regions. Andrew and Fein (In Press) present a between-subjects analysis of P3b amplitude (and it’s reflection in evoked power) on the data of the current study, showing reduced P3b in LTAAs. The effect size was about half that of the findings on induced θ oscillations reported here. This strongly suggests that measures of the induced θ oscillations during target processing are more powerful discriminators of LTAAs and NACs than the P3b (whether examined in the time or time/frequency domain).
