Table 1.

Functional neuroanatomy for the intensivist

	Anatomic structures	Function
Gray matter	Nuclei of cranial nerves	Brainstem reflexes
	Nuclei of ascending reticular activating system (ARAS)	Arousal, sleep/wake cycles, and alertness
	Nuclei of the extrapyramidal system	Automatic movements
	Nuclei of the central autonomic system	Vital function regulation and homeostasis
White matter	Axons of ascending pathways: Posterior column-medial lemniscus pathway Spinothalamic tract and lateral lemniscus pathway	Sensory information: Fine touch, vibration, two-point discrimination, and proprioception Pain and temperature
	Axons of descending pathways: Pyramidal corticospinal and corticobulbar tracts Extrapyramidal tract (rubrospinal, pontine and medullary reticulospinal tract, lateral vestibulospinal and tectospinal tracts)	Voluntary motor control Reflexes, locomotion, complex movements, and postural control