CORTICAL CORRELATES OF SEMANTIC CLASSICAL-CONDITIONING

Event-related potentials to visually displayed pseudowords were regist ered from 13 individuals. In a differential conditioning paradigm, hal f of the pseudowords had previously been paired with a painful electri c shock (shock words) and the other half had been presented without sh ock (nonshock words). Participants were asked to decide if the words h ad been presented during the conditioning phase or not. Larger N100 am plitudes and a mere negative-going slow wave 400-800 ms after word pre sentation were found for shock as compared with nonshock words. This e ffect was stronger over the left than over the right hemisphere. This left-lateralized negativity might reflect the activation of a cell ass embly representing the memory of the learned word-shock contingency. F urthermore, the increased N100 amplitude elicited by shock as compared with nonshock words may be interpreted as an increased attentive faci litation for aversive pain-related information as a consequence of con ditioning.