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 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.

Effects of preparatory period on anticipatory postural control and contingent negative variation associated with rapid arm movement in standing posture

“…The effects of presentation timing of response stimulus on reaction time have previously been investigated using a paradigm of warning stimulus/response stimulus/motor response [11][12][13][14][15][16][17][18]. When the preparation period is constant across trials and only a single response to the response stimulus is required, reaction time reportedly increases with preparation period [19].…”

“…Brain activity during the preparation period in the abovementioned paradigm has been investigated in subjects in a sitting position using contingent negative variation (CNV), which is obtained by averaging EEGs during the period [11][12][13][14][15][16][17][18][21][22][23]. Sources of CNV reportedly include the supplementary motor area [21][22][23], premotor area [21,23] and prefrontal cortex [21,23].…”

Regional Cerebral Blood Flow during Voluntary Movements of the Hand

“…Donchin and Lindsley (1966) believe that reaction time speed can be related to the nonspecific arousal and alerting mechanism. On the other hand, it has been established that the amplitude of the contingent negative variation (CNV) is correlated with the speed and the strength of the reaction elicited when the imperative signal appears (Loveless, 1973;Rebert et al, 1967). In the first half of the reaction time experiment (until the 72nd trial), a variable activation of the nonspecific mediothalamic frontocortical projection system (described by Skinner and Lindsley, 1973) could explain the correlation between precentral flow and reaction time.…”

Event-related slow (DC) potentials in the human brain

“…In addition the potential magnitude was found to be directly proportional to be amount of anticipated force needed for a response (Rebert et al 1967;Low and McSherry 1968). Furthermore, amplitude changes proportional to the anticipated speed of movement in response to $2 were described by Griinewald et al (1979a).…”

“…In these cases higher CNV amplitudes have been found (Low et al 1967;Rebert et al 1967;Faidherbe et al 1969). The increased CNV may indicate a facilitation of sensory processing in these instances, but other factors such as motivation and activation or arousal may also be involved.…”