Theta power during the resting eyes open condition did not differentiate the LTAAs and NACs. The pre-stimulus θ power in the task was larger than the resting θ power, thus showing an enhanced level of stimulus-independent θ synchronization for the task, consistent with higher levels of attention and motivation in the task compared to the resting condition. Furthermore, this enhancement of the task pre-stimulus θ power was larger for the NACs than the LTAAs, as the LTAAs showed significantly reduced pre-stimulus θ power compared to the NACs. After removing variance of the P3b amplitude, the pre-stimulus θ power still significantly discriminated the groups, but the effect size was reduced. This reduction is consistent with proposed oscillatory models of ERP generation where partial phase resetting of δ and θ oscillations contributes to the P300.
