Report of Panel III: Preparatory Processes
|Panel chair:||W. Ritter|
|Panel members:|| S. Kelso|
Ritter: After a brief survey of ERP components such as the CNV and the readiness potential, I shall outline recent changes in thinking about these po tentials. Marta Kutas will then comment on the view that there are several subcomponents to the CNV. Then Scott Kelso will present an analysis of the process of movement control.
The CNV is usually studied while subjects are assigned a warned reactiontime task, in which two stimuli, S1 and S2, are presented and the interval between S1 and S2 is constant. The S1 is the "warning" stimulus, and S2 is a target or "imperative" stimulus to which the subject must somehow respond. Figure 8.1 illustrates the ERPs that are recorded in this situation (note that in my figures, negative is "down"). These data were reported by Simson, Vaughan, and Ritter ( 1977). The interval between S1 and S2 was 1 sec, and the interval between successive presentations of the pair (trials) was 8 sec. S1 was identical on all trials of a given condition and served only as a warning cue. On the other hand, one of two stimuli, chosen randomly, were presented as S2. The subject was instructed to respond to one of these stimuli and to ignore the other (this is often called a "Go-No-Go" task). The two ERPs in the left column of the figure were recorded in a condition in which S1 and S2 were auditory. The waveforms in the right column were elicited by a visual S1 and S2. All these ERPs are recorded at a vertex electrode. The S1 elicited an ERP with a sequence of components. It is clear that auditory and visual stimuli elicit