SUBDURAL POTENTIALS AT ORBITOFRONTAL AND MESIAL PREFRONTAL AREAS ACCOMPANYING ANTICIPATION AND DECISION-MAKING IN HUMANS - A COMPARISON WITH BEREITSCHAFTSPOTENTIAL

Field potentials associated with the execution of a warned choice Go/N o-Go reaction task were recorded from prefrontal, supplementary (SMA) and primary motor cortex (MI) by using subdural electrodes in 5 epilep tic patients during presurgical evaluation. The choice was between a G o and a No-Go imperative stimulus (S2) in the S1-S2 paradigm. Orbitofr ontal and mesial prefrontal areas generated a slow preceding potential before S2 (most likely late CNV), and bilateral mesial prefrontal are as generated a transient potential, most likely related to decision ma king, upon S2 in both Go and No-Go conditions, In self-paced, repetiti ve movement, the Bereitschaftspotential was seen only at SMA and MI, b ut not in the prefrontal area. The present result, therefore, suggests that in humans orbitofrontal and mesial prefrontal areas play an impo rtant role in preparation for cognition and in decision making, wherea s SMA and MI do so in motor preparation.