Stimulus-preceding negativity induced by fear: a manifestation of affective anticipation.

The Stimulus-Preceding Negativity (SPN), a slow cortical potential, has been studied in relation to anticipatory attention. A review of the literature suggests that most instances of SPN are observed in anticipation of motivational stimuli, such as aversive stimuli and stimuli that provide Knowledge of Results. In the present study, SPN was recorded in 12 subjects in a threat-of-shock experiment. This manipulation induced fear, as shown by subjective ratings and potentiation of the eyeblink startle. The fear-induced SPN showed a frontocentral maximum and coarse source analysis suggested that it was generated in midline frontal areas, possibly by the anterior cingulate cortex. It is concluded that the fear-induced SPN is a manifestation of affective anticipation. Possible thalamocortical and amygdalocortical contributions to its generation are discussed.