Slow brain potentials associated with motor preparation and stimulus anticipation

The study was undertaken to analyze the cognitive determinants of event-related potentials (ERPs) under two stimulus paradigm discrimination conditions. We were interested in how the processes of anticipation and preparation for motor action are associated with the ERPs and what is the interrelation between them. Subjects were presented in randomized order three pairs of tones: warning (S1) and imperative (S2) one with different information content. Two ERPs types were studied: (1) The acoustic evoked potentials elicited by warning and imperative stimulus. (2) The early-initial (iCNV) and late-terminal (tCNV) contingent negative variation. Our data suggested that the processing of S2 depends not only on its physical characteristics and information content but also on the prestimulus brain activity reflecting expectancy or motor preparation. The higher iCNV amplitude contralaterally to the movement side under the condition requiring motor action compared to the paradigms without movement preparation could be associated also with the response related processes.