'Error' potentials in limbic cortex (anterior cingulate area 24) of monkeys during motor learning.

Two monkeys were trained to lift a lever with wrist extension in response to a visual cue. The animals were chronically implanted with electrodes for recording transcortical field potentials. Unique 'error' potentials were observed in the anterior cingulate cortical area 24 during a transitional learning-stage when the animals were uncertain about fulfilling the required task appropriately. At that stage (III) about 40-60% of the movements were made appropriately within the required cue-time. Error potentials followed inappropriate lever lifts made with wrist movements that were self-paced and hence non-rewarded, but such potentials did not follow appropriately made, i.e. visually initiated, and rewarded lifts.