Slow potential change in human brain related to level of motivation.

Abstract

Negative slow potential change (contingent negative variation or CNV) in human cortex which develops in the foreperiod of a reaction-time experiment was studied as a function of motivational variables. When the warning signal indicated that a difficult-to-detect auditory stimulus would follow, CNV was greater than when an easily detected stimulus was signaled. Instructing Ss [subjects] to press a key at the onset of the second stimulus resulted in development of larger anticipatory CNV than when no response was instructed. When muscular effort required to complete a response to the 2nd stimulus was varied, larger CNV accompanied greater effort. These findings extend those of other investigators and support the conclusion that CNV reflects cerebral mechanisms related to motivation.