Lateral prefrontal damage affects processing selection but not attention switching.

A challenge for cognitive neuroscience is to determine how the prefrontal cortex (PFC) contributes to the cognitive control operations that oversee thought and action. We studied the effects of damage to the lateral PFC in two types of attentional control. Subjects performed a choice reaction time task that required attention switching and processing selection. The performance of individuals with PFC or parietal cortex damage was compared with that of age-matched and young control subjects. Damage to the lateral PFC did not significantly impair the switch from attending to one color to attending to another. PFC damage did, however, significantly increase the effects of distractor stimuli, implicating the lateral PFC in processing selection. Individual subjects' performance suggested that the left inferior posterior PFC was the most critical for processing selection. Our data are consistent with the view that the lateral PFC contributes to the top-down control of the information flow along pathways from sensory input to motor output.