THE SELF-REGULATION OF SLOW POTENTIAL SHIFTS AND EVOKED-POTENTIALS - INTERRELATIONSHIPS IN RESPONSE TO SOMATOSENSORY STIMULATION

Research on the effects of the self-regulation of event-related potent ials (ERP) has failed to investigate the possible interactions and con tributions of slower cortical events such as contingent negative varia tions (CNV) and slower DC level changes. The present study attempted t o investigate such interactions by independently conditioning the ERP 200 ms poststimulus (P200) and the CNV while recording both potentials simultaneously; DC level measures were also recorded. 30 subjects att empted to increase (uptraining) or decrease (downtraining) either P200 or CNV in response to sub-painful somatosensory stimulation in a biof eedback paradigm. Following the training sessions, P200 downtrainees r eported a significant decrease in their detection thresholds for the s omatosensory stimuli (i.e., increased sensitivity). These results agre e with some prior findings that decreased ERP amplitude in individuals is indicative of greater sensitivity in subjective pain reports. Alth ough uptraining resulted in larger P200 amplitudes than downtraining, the difference in amplitudes between groups was not significant. CNV u ptrainees achieved a higher level of pain tolerance following training . The increased CNV negativity may be associated with increased specif ic attentional processes that facilitate the subjects' control of, or response to, pain. CNV trainers showed a significant interaction of tr aining over blocks of trials. Generally, there was a significant inver se correlation of P200 and CNV; as CNV amplitude became more negative, the P200 amplitude increased. DC negativity level increased over bloc ks for all conditions. Results indicate a complex relationship between P200, CNV and pain sensitivity. Both P200 and CNV processes are invol ved in pain perception, but in apparently different ways, i.e., P200 w ith sensitivity and CNV with tolerance.