Metacognitive and online error awareness deficits after prefrontal cortex lesions.

Awareness of deficits after brain injury represents a significant clinical and theoretical challenge, but relatively little is known about the neuroanatomical correlates of specific types of deficit awareness. We examined the awareness correlates of left versus right prefrontal cortex lesions in comparison to left and right posterior lesions including two types of awareness measures--metacognitive and online error monitoring. Frontal lobe frontal lesion patients exhibited impaired metacognitive awareness and also showed deficits in monitoring errors as they occurred. In addition, frontal lobe lesion patients also showed reduced autonomic response to aware errors. Online and metacognitive awareness were not, however, significantly correlated, suggesting that distinct neuroanatomical systems may underpin these two types of awareness deficit. We hypothesize that while metacognitive awareness depends on both left and right frontal regions, accurate moment-to-moment processing of errors depends more on the right than on the left prefrontal cortex.