Slow Cortical Potentials in Subjects With High or Low Scores on a Questionnaire Measuring Physical Anhedonia and Body Image Distortion.

Slow cortical potentials, response speed, and peripheral physiological responses were investigated in two experiments with four groups of male subjects. Experiment 1 examined constant foreperiod reaction time in a sound light button press sequence with an interstimulus interval of 2 sec. Experiment 2 investigated constant foreperiod reaction time conditions with a sudden change from controllable to uncontrollable offset of an aversive imperative stimulus. There were two visual warning stimuli of 6-sec duration followed by an aversive or neutral imperative stimulus to be terminated by button press within I sec. Forty trials of this contingency were followed by 40 trials with 5-sec duration of imperative stimuli irrespective of response speed. Subjects were selected by high or low scores on two questionnaire scales measuring physical anhedonia (PA) and body image distortion (BI). In the first paradigm subjects with high PA scores as compared to low-scoring subjects showed less resolution of left precentral CNV after S2, i.e., a more pronounced post-imperative negative component. In the second paradigm a postimperative negative variation (PINV) developed in all groups, but was more pronounced in frontal recordings and in subjects with high PA and BI scores. Results are discussed in the context of electrocortical phenomena observed in psychopathological groups. [ABSTRACT FROM AUTHOR]