Disturbances of consciousness and sleep-wake functions in patients following brainstem lesions

Abstract: Sleep-wake and circadian rhythmicity including several vital functions are regulation by complex interplay between basic structures in the brain: brain stem, thalamus, hypothalamus and basic forebrain. Discrete but interconnected clusters of cells located within the brainstem and hypothalamus comprise the circuits that generate wakefulness, non-rapid eye movement (non-REM) sleep, and REM sleep. The hypocretin system plays a function for wake and REM/NREM regulation including reticular activating system (RAS) projects to brain regions via complex projections via thalamus and forebrain. The circadian system involves suprachiasmatic nucleus (SCN) in the hypothalamic region with projections to several system, including a complex cervical parthway to the pineal gland secreting melatonin. As such several lesions may cause disturbances in these regulatory functions. Examples includes specific lesion in inferior hypothalamic region which may involve SCN (circadian disturbances), the ventrolateral preoptic nucleus or its projections (loss of sleep regulation), bi-thalamic lesions (somnolence), to pontine region (REM regulation disturbances), sublaterodorsal nucleus (REM sleep Behavior Disorder), to the hypocretinergic system (narcolepsy with cataplexy), cervical lesion or pineal gland (abolished melatonin secretion). Such lesions may include neurodegeneration (alpha-synucleinopathies, tauopathies), stroke, tumors, inflammations including autoimmune involvement. Disclosure: Nothing to disclose.