Exposure to uncontrollable stress and the postimperative negative variation (PINV): prior control matters.

The main goal of this study was to assess cortical functioning as indexed by the postimperative negative variation (PINV) induced by uncontrollable stress. Sixty-six persons were randomly assigned to three groups who underwent different sequences of stressor controllability. Within an S1-S2 paradigm, one group had initial control over aversive stimulation followed by loss of control and restitution of control.