Pathological laughter. A review of the literature.
Normal laughter is a unique human behavior with characteristic facial and respiratory patterns elicited by a variety of stimulus conditions. The neuroanatomy remains poorly defined but three levels seem likely: a) a cortical level; b) a bulbar, or effector, level; and 3) a synkinetic, or integrative, level probably at or near the hypothalamus. Pathological laughter occurs when laughter is inappropriate, unrestrained (forced), uncontrollable, or dissociated from any stimulus. Pathological laughter is found in three main conditions: a) pseudobulbar palsy; b) gelastic epilepsy; and c) psychiatric illnesses. It is also found in other pathological conditions. What brings these together is their clinical similarity and probable disinhibition at higher brainstem levels.
D000339:Affect / Q000502:physiology; D000818:Animals; D001921:Brain / Q000502:physiology; D010244:Bulbar Palsy, Progressive / Q000523:psychology*; D004827:Epilepsy / Q000523:psychology*; D006801:Humans; D007046:Hysteria / Q000523:psychology; D007845:Laughter; D001523:Mental Disorders / Q000523:psychology*; D009434:Neural Pathways / Q000502:physiology; D009497:Neurotic Disorders / Q000523:psychology; D012565:Schizophrenic Psychology