Two oddball tasks, one visual, the other auditory, which have been used in the COGA neurophysiology battery from the inception of the project (Cohen et al., 1994; Alexander et al., 1994) were used for this study. In each task, subjects were verbally instructed to suppress their eye blinks and to sit as still as possible. They were asked to respond to the target with a button press as quickly as possible, but not at the expense of accuracy, and not to respond to other stimuli.
