Spatial Distribution of the Contingent Negative Variation (CNV) and the Relationship between CNV and Reaction Time

Multichannel recording of scalp CNV (Contingent Negative Variation) and RT (Reaction Time) was carried out on 12 normal adult Ss in a fixed foreperiod RT experiment. Single trial responses were stored on digital tape and averaged off‐line. Strict control over eye movement artifact was exerted through fixation techniques coupled with mechanical and electro‐oculographic monitoring of movement. Analysis of single‐trial data gave an intra‐individual picture of correlation apparently in conflict with the across picture gained from averages. A rationalization is attempted of these results and some evidence is offered that, in the individual S, a negative and probably nonlinear relationship holds between CNV amplitude and RT. Analysis of average data demonstrates the distribution of CNV across the scalp and shows a lack of correlation between CNV and RT in prefrontal areas, in contrast with that found in central‐parietal areas. It is suggested that the CNV is an index of functionally different processes in these areas.