The neural correlates of impaired consciousness in coma and unresponsive states

Over the last few years, functional neuroimaging studies have provided new insights into cerebral activity in subjects with severe brain damage leading to coma and other clinical states characterized by unresponsiveness. The present paper introduces the clinical picture of patients with impaired consciousness, and reviews the nosological criteria and functional neuroanatomical basis for brain death, coma, vegetative state, minimally conscious state, and the locked-in syndrome. Converging evidence suggests that disrupted activity in higher-order association areas, especially prefrontal and posteromedial parietal regions, plays a pivotal role within the neural correlates of impaired consciousness in the unresponsive patient.