the frontoparietal control network (FPCN). Because these networks contribute to internal and external cognition, abnormalities in the PCC might contribute to psychosis in some types of schizophrenia. Traumatic brain injury After traumatic brain injury (TBI), abnormalities have been shown in the PCC. Often, head injuries produce widespread axonal injury that disconnect brain regions and lead to cognitive impairment. This is also related to reduced metabolism within the PCC. Studies of performance on simple choice reaction time tasks after TBI show, in particular, that the pattern of functional connectivity from the PCC to the rest of the DMN can predict TBI impairments. They also found that greater damage to the cingulum bundle, that connects the PCC to the anterior DMN, was correlated with sustained attention impairment. In a subsequent study, it was found that TBIs are related to a difficulty in switching from automatic to controlled responses. Within selected tasks, patients with TBI showed impaired motor inhibition that was associated with failure to rapidly reactive the PCC. Collectively, this suggests that the failure to control the PCC/DMN activity can lead to attentional lapses in TBI patients. Anxiety disorders There is accumulating evidence for PCC dysfunction underlying many childhood/adolescent-onset mental disorders. Further, anxiety disorder patients show an association between increased extinction–related PCC activity and greater symptom severity. PCC dysfunction may also play a role in anxiety disorders during adolescence. See also Cingulate cortex Cingulum References External links For details regarding MRI definitions of the cingulate cortex based on the Desikan-Killiany Brain atlas, see: Medial surface of cerebral hemisphere Gyri