Role of the frontal lobes on an attention task: a signal detection analysis.

Sensitivity and criterion were studied on an attention task requiring detection of new stimuli for a group of 20 patients with unilateral hemispheric damage restricted to the anterior or posterior areas. Patients performed a simple attention task, in which the presence of a novel stimulus had to be detected against the repetition of the same stimulus repeated. Only the site of the lesion (anterior vs posterior damage) influenced the performance of the task. In fact, frontal patients had both lower capacity to discriminate between signals and nonsignals and lower confidence in their responses.