CAN THE LEVEL OF PREFRONTAL ACTIVITY PROVIDE AN INDEX OF PERFORMANCE IN HUMANS

The experiment reported here was aimed at determining whether the leve r of brain activity can be used as an index of subjects' performance o n a temporal task. The discrimination of durations constituted the tas k. An array of four A's appeared on a screen, and subjects had to deci de whether the letters remained on the screen for a short or a long du ration as learned in a practice phase. This task allowed us to compare the level of brain activity obtained in correct and incorrect respons es. The current density measures recorded over prefrontal areas showed that the level of activity obtained with correct responses was lower than those obtained with incorrect responses. This suggests that a goo d performance could be the result of an economic, but efficient, infor mation-processing mechanism in the brain.