On the other hand, and more importantly, task-difficulty effects arose only later in the preparation phase, as reflected by an interaction effect in the late CNV component. Specifically, CNV differences following cues predicting high-difficulty versus low-difficulty targets were more apparent in reward trials compared to no-reward trials, but only in the late part of the CNV. As a consequence, the most negative going wave was observed for high-difficulty reward trials. Importantly, this difference in task preparation indeed affected subsequent target-discrimination performance, indicated by the fact that participants with a larger difference in late CNV amplitude between high-difficulty and low-difficulty cues in the reward condition also showed faster responses for high-difficulty reward targets compared to low-difficulty reward ones. Such correlations between CNV amplitude and behavioral performance have been shown before (Birbaumer et al., 1990; Fan et al., 2007; Haagh and Brunia, 1985; Wascher et al., 1996) and correspond to the notion that the CNV reflects both motor preparation and attention or stimulus anticipation (Connor and Lang, 1969; Rohrbaugh et al., 1976; Tecce, 1972; van Boxtel and Brunia, 1994). It has to
