behavioral and autonomic variables can be monitored. It is still unclear whether the operantly modified brain responses and behavioral/autonomic con­ comitants are directly, causally linked together; the possibility of motor and visceral mediation of the conditioned brain responses remains to be clarified. However, the contributions to this volume clearly demonstrate a rather specific relationship between different conditioned responses from various parts of the brain and some unique behavioral consequences. Operant conditioning of the sensorimotor rhythm in the postcentral area "produces" motor quiescence (see Sterman, Chapter 7 and Lubar, Chapter 8); first results suggest that the conditioning of left postcentral negative slow potential shifts are closely related to the contralateral sensoric task performance (as described by Rockstroh, Elbert, Lutzenberger, & Birbaumer, Chapter 15).