Left inferior frontal cortex is involved in probabilistic serial reaction time learning

Cerebral blood flow was estimated using positron emission tomography and H2 O15 infusions in 12 volunteers while they were trained on the probabilistic serial reaction time task developed by Jimenez, Mender, and Cleeremans (19 96). Participants' reaction rimes to predictable and nonpredictable stimuli showed increasing sensitivity to the: probabilistic constraints set by pre vious elements of the sequence. Analysis by statistical parametric mapping showed a significant interaction between participants' performance and time effect in the left inferior frontal cortex. Our results provide the first evidence of this cerebral area being involved in the processing of contextu al information in a probabilistic sequence learning task. (C) 1999 Academic Press.