FIGURE 9-3 Levels of brain function in different disorders of consciousness. A. Brain death results in no brain function in the cortex, subcortex, or brainstem. B. Coma results in severely depressed function in the cortex, subcortex, and reticular activating system of the brainstem. C. Persistent vegetative state results in severely depressed cortical function, but variably depressed function in the subcortex and reticular activating system. D. Minimally conscious state results in variably depressed function in the cortex, subcortex, and reticular activating system.