Journal of Neurology, Neurosurgery, and Psychiatry, 1972, 35, 108-113 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.35.1.108 on 1 February 1972. Downloaded from

Released involuntary laughter after temporal lobe infarction

MICHAEL SWASH From the Department of Neurology, Section of Neurological Sciences, The London Hospital, London

SUMMARY A case of sustained involuntary laughter is described, with accompanying alteration ot mood, due to infarction of the inferior and lateral aspects of the left temporal lobe. The lesion was localized by the clinical findings, by electroencephalography, by a radioisotope scan, and by angiography. The problem of the neurology of emotional behaviour is discussed in the context of the localization of the lesion in this case.

Changes in emotional state are common in that she seemed to be continuously muttering and neurological disease but involuntary laughter laughing to herself. In this state loud laughterguest. Protected by copyright. occurring either as an epileptic event (gelastic occurred in response to any environmental stimulus. ) or as a released phenomenon in destruc- Any attempt at conversation, or even the noise of a and door slamming, induced a burst of loud, natural- tive lesions is very rare. Gumpert, Hansotia, sounding laughter which often continued for five or Upton (1970) have recently described one further 10 minutes. She seemed to understand what was case of gelastic epilepsy and have reviewed some said to her but her own speech was jumbled and of the previously reported instances of patho- incomprehensible, and when asked to write down logical laughter. They were unable to draw any what she wanted she wrote nonsense. During the firm conclusions about the nature of the under- night she was quiet, although her husband had lying mechanisms responsible for the production difficulty in preparing her for sleep because of her oflaughter in their patient, although they thought noisy laughter. The next morning she woke at that a hypothalamic lesion was the most likely the usual time, but immediately began to laugh cause. uncontrollably and with apparent , and was brought to the hospital, still laughing and It is the purpose of this paper to present a case giggling. of sustained involuntary laughter, with accom- There was no history of previous physical or panying alteration of mood, due to left temporal psychiatric illness and there was no family history of lobe infarction. vascular disease. Menstruation had ceased seven

years previously. http://jnnp.bmj.com/ On examination she was an obese woman lying on CASE REPORT her right side in a generally flexed posture chuckling Mrs. D.E.G. (LH 31891/57), aged 45 years, was and laughing to herself in a natural but wholly admitted to the London Hospital as an emergency. inappropriate manner. Frequent noisy yawns inter- She had been well until the evening before admission rupted her otherwise almost continual and often when she suddenly began to laugh. Her laughter was noisy laughter. She responded to simple questions by loud and continuous and although it was obviously nodding or shaking her head and with louder and inappropriate it seemed, in itself, to be like her usual more prolonged laughter. Sometimes she muttered on September 26, 2021 by laughter, so that her husband thought, at first, that inaudibly. If left alone she became drowsy and something had amused her. However, she continued drifted into a light sleep from which she could easily laughing and was unable to stand unaided or use her be awakened by calling her name. Her laughter was right arm to support herself. During the first hour so natural and so apparently enjoyable that it pro- her right arm flung wildly about in the air. She voked amusement and laughter among the physi- laughed almost continuously for the first three cians, nurses, and other patients who saw her, hours, with pauses only to draw breath, but then her although it was plain to them that her laughter was laughter gradually subsided and was replaced by both involuntary and pathological. Even her husband frequent giggles, low laughs, grimaces, and smiles so found it difficult not to laugh with her. She did not 108 Released involuntary laughter after temporal lobe infarction 109 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.35.1.108 on 1 February 1972. Downloaded from make puns or and there was no word associa- Writing of remembered material-for example, her tion or flight of ideas. address-and of copied sentences showed similar She moved all limbs voluntarily and to command, errors. There was no gross limb apraxia or agnosia. but the right arm was consistently moved less than A right upper quadrantic visual field defect per- the left and the stretch reflexes were exaggerated in sisted and she often neglected right-sided visual and this limb. The right plantar response was extensor auditory stimuli. There was a mild right hemi- and the left flexor. There was a right facial weakness paresis, most marked in face and shoulder, and the of supranuclear type which was less obvious during right-sided stretch reflexes were brisk. The right the almost continuous mimetic facial movement plantar response was extensor. There was impair- than during voluntary movement. She responded less ment to all sensory modalities in the right limbs but well to painful stimuli in the right arm than elsewhere. perseveration and aphasia made detailed examina- The visual acuity was normal but there was a right tion impossible. upper quadrantic field defect to confrontation with The skull and chest radiographs and routine bilateral, simultaneously presented, stimuli. The haematological and urine tests were normal. An pupils were normal. The general examination was electroencephalogram showed poorly organized within normal limits and the blood pressure was background activity bilaterally and a focus of theta 115/75 mm Hg. and delta activity in the left fronto-temporal region. By the third day she was improved and could sit The brain scan (Tc99m) showed increased uptake of out in a chair. However, even at rest she still smiled radioisotope in the deep and inferior aspects of the and chuckled to herself without apparent cause and left temporal region (Figure) but an echoencephalo- when her attention was attracted by auditory or gram showed no shift of the midline echoes from the visual stimuli she burst into prolonged and hearty acoustical midline. A left carotid angiogram, per- laughter. Each laugh seemed to precipitate another, formed by left common carotid puncture, showed guest. Protected by copyright. so that louder and longer peals of laughter succeeded deformation of the stream of contrast medium by each other, speech was impossible, and her whole atheroma at the carotid bifurcation and reduction of body seemed to be taken up with laughter and the flow of contrast in the territory of an insular and respiration. It was possible, however, to modify the an anterior temporal branch of the left middle degree of her mirth. Even a faint from the cerebral artery (Dr. Leon Morris). Only the origin examiner provoked instant violent laughter but and proximal part of the anterior temporal vessel these outbursts could be slowly and partially sup- could be seen and filling of its terminal branches pressed by a serious or factual question or by an occurred retrogradely through leptomeningeal anas- emotionless expression on the part of the examiner. tomotic vessels. The CSF was clear and colourless She could not voluntarily suppress her laughter as and contained 30 mg protein/100 ml. The WR was when requested to 'stop laughing'. Such commands negative in both blood and CSF. The serum uric only increased the laughter. Her laughter was always acid and an oral glucose tolerance test were normal. accompanied by reddening of the face, an alteration offacial expression, by hand and arm movement, and PROGRESS Improvement continued during the next sometimes by tear formation appropriate to the month, although throughout this time prolonged degree of mirth. During these episodes of laughter bursts of loud, inappropriate laughter could be she would sometimes say 'funny, funny'. Inappro- elicited by sympathetic smiles or by slightly - priate crying, fear, or were not observed at ous stimuli presented either visually or verbally. She this or any other time in her illness. continued to smile and chuckle to herself without http://jnnp.bmj.com/ She was unable to describe the events of her illness apparent cause but this phenomenon gradually or to talk about her home and although she responded became less evident. On questioning she admitted to simple commands she failed to perform two-stage that her laughter was abnormal but could not requests. Perseveration, both of speech and of explain what it was that she found amusing or why gesture, was very marked and normal prosody was she laughed so easily. She was adamant that she was lost. She often spoke spontaneously, but in a soft actually amused during the act of laughing. She was mumbling voice, and her speech contained frequent rarely downcast and was never seen to be

depressed, on September 26, 2021 by neologisms and repeated meaningless phrases. She or to cry, or weep, although she clearly understood could not repeat simple phrases either verbally or in that she had had a stroke. writing. There was a severe naming defect both to Six weeks after the onset ofher illness she returned visual and tactile tests, although it was clear that she from convalescence. She remembered and described knew the use of the objects presented. There was no the period of continuous laughter in detail and with echolalia. Calculations were performed inaccurately, amusement, although she realized that it was ab- but not out of proportion to the degree of aphasia, normal. She still laughed suddenly and too easily but and there was no significant left-right disorientation. was able to control these outbursts by a conscious During reading aloud neologisms and perseveration effort. She had had no visual or auditory hallucina- were prominent and comprehension was very poor. tions. She was aware that her speech was still not 110 Michael Swash J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.35.1.108 on 1 February 1972. Downloaded from

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FIGURE Left lateral and AP radioisotope brain scan, showing an area of increased uptake of isotope in the lateral, anterior, and inferior aspects of the left temporal region. normal. On examination she was euphoric and matter, extending into the hemisphere as far as

humourous and speech was frequently interrupted the genu of the internal capsule. The significanceguest. Protected by copyright. by sudden and often unexpected bursts of laughter of the flinging movements of the right arm at the which were quickly and voluntarily inhibited. She onset of the illness is uncertain. There was no was still easily distracted by random events in her environment and she was unable to attend to any evidence, from the clinical information, of any task for more than a minute or so. The resultant other lesion in the nervous system. Her laughter sudden changes of attention were particularly likely was neither epileptic nor part of an epileptic to be accompanied by a burst of laughter. There was aura. There was no history of cyclic variations in a mild residual aphasia and the right upper quad- mood and the clinical features of her laughter rantic visual field defect and the mild right-sided were unlike those found in psychiatric disease. signs persisted. In our patient the lesion was left sided. Poeck The electroencephalogram was improved but and Pilleri (1963) found a left-sided lesion in six showed similar abnormalities to the previous patients and a right-sided lesion in four patients recording. A repeat left carotid angiogram again with pathological laughing and crying who were showed a paucity of vessels in the left anterior shown, at necropsy, to have single lesions in the temporal region, but collateral and anastomotic nervous system. In all their cases the lesion was vessels were more extensive. The radioisotope brain scan still showed increased uptake of isotope in the subcortical, extending into the anterior limb of left inferior temporal region but a third scan per- the internal capsule together, in three cases, with formed four months after the first showed less up- the adjacent caudate nucleus, in four with the http://jnnp.bmj.com/ take in this region, and this seemed compatible with left putamen, in four with the left claustrum and the diagnosis of cerebral infarction. the external and extreme capsules, and in three At home she was at first unable to do much house- with insular cortex. The and work and was embarrassed by her tendency to laugh brain-stem were spared in all their cases. Poeck at inappropriate moments, but a year later she had (1969) has not observed pathological laughter or taken part time employment as a packer on an crying with a single circumscribed cortical lesion assembly line. At this time she still had some and this experience is in accord with the clinical difficulty performing fine coordinated tasks with evidence of infarction extending from temporal on September 26, 2021 by her right hand and her friends still noticed that she cortex to internal capsule in our patient. The laughed too easily. relative sparing of right facial movement during smiling and laughing may have an anatomical DISCUSSION explanation, since the lesion must have spared the central fibres subserving this emotional The clinical evidence strongly supports a diagno- movement. These fibres are thought to travel sis ofinfarction of the lateral and inferior aspects through the thalamus (Monrad-Krohn, 1924), of the left temporal lobe and its underlying white and not through the internal capsule, and there- Released involuntary laughter after temporal lobe infarction III J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.35.1.108 on 1 February 1972. Downloaded from

fore this finding may be further evidence that the alteration of emotional state without weeping or thalamus was not involved in the lesion. crying for the remainder of the patient's life, and Involuntary laughter may occur as a released she remained incontinent and demented with a phenomenon with destructive lesions or as part double hemiplegia until her death some months of an epileptic discharge (gelastic epilepsy). Thus later. Post mortem examination was not per- it is commonly released in pseudobulbar states formed but it is clear from the clinical description and very rarely as a prodrome of cerebral that this patient had multiple, bilateral cerebral haemorrhage or infarction. It is extremely rare infarcts and, although Ironside regarded the for it to occur as a released phenomenon with case as an example of 'le fou rire prodromique' single cerebral lesions, as in our patient. Laughter (Fere, 1903), it is difficult to exclude a pseudo- may also be released after prefrontal lobotomy bulbar cause for the laughter. Our patient, how- (Kramer, 1954), and in psychiatric disorder when ever, is an example of the extremely rare pheno- it is part of a more generalized disturbance of menon of released laughter occurring as a sequel function. These various categories of involun- to a single cerebral lesion. tary laughter will be discussed briefly. Gelastic epilepsy is a rare phenomenon and its Released involuntary laughter, usually accom- pathophysiology is not understood. Some of the panied by involuntary weeping and crying, is a reported cases have been associated with tem- common finding in patients with diffuse or poral lobe tumours (Daly and Mulder, 1958) or multifocal lesions in cerebral hemispheres or with temporal EEG discharges both in the resting brain-stem. It is usually taken to indicate bi- record and actually during the attacks oflaughter lateral lesions. The laughing and weeping may (Weil, Nosik, and Demmy, Roger, Lob,

1958; guest. Protected by copyright. occur spontaneously or as an exaggerated re- Waltregny, and Gastaut, 1967), but suppression sponse to a minor stimulus and it is usually of paroxysmal EEG activity during the attacks obvious from the quality, intensity, and duration has also been observed (Druckman and Chao, of the response that it is pathological, so that it 1955; Gumpert et al., 1970). In patients with only rarely stimulates similar emotions in temporal lobe epilepsy ictal laughter is very rare experienced observers. (Daly, 1958; Weil, 1959) but sensations of ictal Released involuntary laughter may occur as a pleasure, without laughter, occur more fre- prodrome ofcerebral haemorrhage or infarction. quently, and feelings of fear or anger are quite Fere's (1903) patient was a 64 year old man who common (Williams, 1956; Currie, Heathfield, laughed suddenly and loudly for several minutes Henson, and Scott, 1971). Penfield and Jasper without cause on several occasions and after one (1954) never observed laughter during their such attack had a left hemiplegia. During the experiments with electrical stimulation of the remaining 18 months of life he had no further human , but Sem-Jacobsen and attacks of laughter. Badt (1927) and Andersen Torkildsen (1960) reported smiling accompanied (1936) have described similar instances of patho- by a feeling of joy, and, in one case, laughter, logical laughter occurring with fatal haemorrhage when stimulating a temporal lobe. into both thalami and both internal capsules. Other clinical reports ofepileptic laughter have Martin (1950) described a patient with a large described lesions in the basal ganglia, in the http://jnnp.bmj.com/ aneurysm of the basilar artery which deformed hypothalamic region and in the walls of the third the upper brain-stem and the posterior part of ventricle. These reports have been discussed in the third ventricle whose death from rupture of some detail by Ironside (1956) and more recently the aneurysm was preceded by an attack of pro- by Gumpert et al. (1970) and by Gascon and longed laughter. Lombroso (1971). Many of the reports of Involuntary laughter may also occur as a laughter occurring with hypothalamic disorders released phenomenon after a single cerebral cited by these authors, and a case of laughter on September 26, 2021 by infarct, but this is extremely rare (Poeck and caused by surgical manipulation of the walls of Pilleri, 1969). Ironside (1956) described a patient the third ventricle (Foerster and Gagel, 1933), with cerebral vascular disease whose third stroke have described states of excitement, depression, was heralded by a sudden feeling of dizziness fear, and anger as well as outbursts of laughter. after which she laughed continuously for three These symptoms are, perhaps, more closely hours. She was then found to have a right hemi- related to pseudobulbar laughing and crying paresis with aphasia. The tendency to laughter than to gelastic epilepsy. persisted as an immoderately easily induced Released laughter occurring after prefrontal 112 Michael Swash J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.35.1.108 on 1 February 1972. Downloaded from lobotomy (Kramer, 1954) is pathological in the laughter there was no accompanying change of sense that it is abnormal but is not involuntary emotional feeling (Martin, 1950; Wood et al., since it is always the result of stimulation, either 1958) our patient always experienced an appro- internal or from the environment. It is always priate alteration of mood during her involuntary accompanied by a sense of amusement. Laughter laughter, smiling and chuckling. In pseudo- as a symptom of psychiatric disorder is similar to bulbar disorders some patients with involuntary that occurring after prefrontal lobotomy and can laughter experience an accompanying change in be distinguished from involuntary laughter due emotional feeling but others do not (Ironside, to neurological disease by the presence ofthought 1956). In temporal lobe epilepsy ictal changes in disorder or flight of ideas and by the character- emotional expression, with accompanying chan- istic accompanying disorder of affect and be- ges in affect, occur relatively frequently and Sem- haviour. Focal neurological signs are not present Jacobsen and Torkildsen (1960) have recorded in such cases. feelings of joy accompanying the smiling and The localization of lesions responsible for both laughter induced by electrical stimulation of the released and epileptic involuntary laughter has human temporal lobe. In destructive cerebral excited considerable interest. While hypothalamic lesions the association of a sense of amusement lesions may release involuntary laughter, as the or joy with involuntary laughter, or the lack of review of Gumpert et al. (1970) confirms, it, is likely to be dependent on the location of the Ironside (1956), who himself thought that the lesion or lesions responsible. Such an association role of the hypothalamus in emotional disorders seems more likely to occur if functional temporal had been underestimated, was careful to point connections with deeper structures are main- out that such disorders could be released or tained and in our case, for example, there is evi-guest. Protected by copyright. could occur as epileptic phenomena with lesions dence that the thalamus was not involved in the both at lower and higher levels in the nervous lesion. It is clear from the cases of involuntary system. Alpers (1940) commented similarly that laughter cited from the literature that patients the hypothalamus is only one of a series of with lesions in thalamus, hypothalamus, or stations concerned with the control of emotional brain-stem do not usually experience an accom- feeling and behaviour. Nonetheless the hypo- panying sense of amusement or joy, but when thalamus has come to be regarded as of special involuntary laughter occurs with lesions in the importance in this regard (Masserman, 1941). temporal lobe, as in temporal lobe epilepsy, a The evidence for this view rests largely upon feeling of amusement is more likely to accom- descriptions of cases of released or ictal laughter pany it. associated with tumours or haemorrhages in this Kliver and Bucy (1939) noticed that the region. Caution must, however, be exercised normal emotional reactions of fear and anger when interpreting the localization of disorders of were absent in the monkey after bilateral tem- function in such cases, since it is not usually poral lobe excision, although they, and others possible to state with certainty that the disordered (Horenstein and Conomy, 1969), have not function was released as a consequence of de- observed such changes after unilateral temporal struction of tissue by the tumour itself, or be- lobectomy. In man bilateral temporal lobectomyhttp://jnnp.bmj.com/ cause of surrounding oedema, infiltration, or has produced a similar psychological disorder to displacement of nearby structures by the tumour. that observed in the monkey (Terzian and Ore, The cases of hypothalamic tumour with ictal 1969). Infarction of the inferior surface of both laughter and precocious puberty described by temporal lobes and of the underlying white Dott (1938) and List, Dowman, Bagchi, and matter in man gives rise to a state of agitated Bebin (1956) cited by Ironside (1956) and by delirium with visual agnosia, compulsive oral

Gumpert et al. (1970) are open to this criticism tendencies, and reduced emotional responses, on September 26, 2021 by and the point is further exemplified by the case of although pseudobulbar laughing and crying Wood, Svien, and Daly (1958). In this latter occurred when the lesions were more extensive patient gelastic epilepsy occurred in association (Horenstein, Chamberlin, and Conomy, 1967). with a neurofibroma of the trigeminal nerve This syndrome must clearly be related to the which had deformed the inferomedial aspect of Kluver-Bucy syndrome as observed in monkeys. the left temporal lobe, the hypothalamus and Papez (1937) and MacLean (1955) have dis- other basal structures. cussed the role of the temporal lobe, and of the Although in other cases of involuntary of which it is a part, in the control Released involuntary laughter after teniporal lobe infarction 113 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.35.1.108 on 1 February 1972. Downloaded from of emotional feeling and behaviour. In their Gascon. G. G., and Lombroso, C. T. (1971). Epileptic (gelastic) laughter. Epilepsia, 12, 63-76. scheme the temporal lobes act as higher integra- Gumpert, J., Hansotia, P., and Upton, A. (1970). Gelastic ting cortex within the limbic apparatus and are epilepsy. Journal of Neurology, Neurosurgery, atid Psy- closely connected through this system with the chiatry, 33, 479-483. Horenstein, S., Chamberlin, W., and Conomy, J. P. (1967). hypothalamic, cingulate, and brain-stem path- Infarction of the fusiform and calcarine regions: agitated ways which have themselves been the site of delirium and hemianopia. Transactions of the Amtiericatn lesions in the cases of involuntary laughter dis- Neutrological Association, 92, 85-89. Horenstein, S., and Conomy, J. P. (1969). Oral prehension cussed above and in the reviews of Ironside and impaired visual discrimination after basal temporal (1956), Gumpert et al. (1970), and Gascon and lobectomy. Transactions of the American Neutrological Lombroso (1971). Smythies (1970) has recently Association, 94, 279-282. Ironside, R. (1956). Disorders of laughter due to brain reviewed the anatomical and physiological lesions. Brain, 79, 589-609. evidence for this role of the limbic system in the Kramer, H. C. (1954). Laughing spells in patients, after lobotomy. Joutrnal of Nervouts and Mental Diseases, 119, control ofemotional and other behaviour in man. 517-522. The precise localization of lesions causing Kliuver, H., and Bucy, P. C. (1939). Preliminary analysis of released laughter without accompanying crying, functions of the temporal lobes in monkeys. Archives of Neurology and Psychiatry, 42, 979-1000. fear, or anger is uncertain, but there is some List, C. F., Dowman, C. E., Bagchi, B. K., and Bebin, J. evidence (see Smythies, 1970) that lesions in the (1958). Posterior hypothalamic hamartomas and ganglio- most medial part of the inferior aspect of tem- gliomas causing precocious puberty. Neuirology, 8, 164-174. MacLean, P. D. (1955). The limbic system ('visceral brain') poral lobe are more likely to produce this and emotional behavior. Archives of Neutrology and isolated functional disorder. The clinical in- Psychiatry, 73, 130-134. Martin, J. P. (1950). Fits of laughter (sham mirth) in organic

formation in our case is not sufficient to allow guest. Protected by copyright. cerebral disease. Brain, 73, 453-464. such precise localization, although the role of the Masserman, J. H. (1941). Is the hypothalamus a center of temporal lobe is clearly demonstrated. emotion? Psychosomatic Medicine, 3, 3-25. Monrad-Krohn, G. H. (1924). On the dissociation of volun- tary and emotional innervation in facial paresis of central I would like to thank Dr. R. A. Henson for allowing origin. Brain, 47, 22-35. me to report this patient, who was under his care, Papez, J. W. (1937). A proposed mechanism of emotion. and Dr. D. F. Scott for critically reviewing the Archives of Neurology and Psychiatry, 38, 725-743. manuscript. Penfield, W., and Jasper, H. H. (1954). Epilepsy and the Functional Anatomy of the Hutman Brain, pp. 141, 447-451. Little, Brown: Boston. REFERENCES Poeck, K. (1969). Pathophysiology of emotional disorders associated with brain damage. Handbook of Clinical Alpers, B. J. (1940). Personality and emotional disorders Neurology, vol. 3, pp. 343-367. Edited by P. J. Vinken associated with hypothalamic lesions. In The Hypo- and G. W. Bruyn. North-Holland: Amsterdam. thalamuis. Proceedings of the Association for Research in Poeck, K., and Pilleri, G. (1963). Pathologisches Lachen und Nervouts and Mental Diseases, 20, 725-752. Weinen. Schweizer Archiv ffir Nelurologie und Psi'chiatrie, Andersen, Ch. (1936). Crise de rire spasmodique avant deces: 92, 323-370. hemorragie thalamique double. Jouirnal Belge de Neiurologie Roger, J., Lob, H., Waltregny, A., and Gastaut, H. (1967). et de Psychiatrie, 36, 223-227. Attacks of epileptic laughter: on S cases. Electroeticephalo- Badt, B. (1927). Lachen als erstes Symptom eines apoplek- graphyv and Clinical , 22, 279 (abstract). tischen Insultes. Zeitschrift fiur die gesamte Neitrologie lund Psychiatrie, 110, 297-300. Sem-Jacobsen, C. W., and Torkildesen, A. (1960). Depth Currie, S., Heathfield, K. W. G., Henson, R. A., and Scott, recording and electrical stimulation in the human brain. D_ F. (1971). Clinical course and prognosis of temporal In Electrical Stutdies on the Unanesthetized Brain, pp. 275- http://jnnp.bmj.com/ lobe epilepsy. A survey of 666 patients. Brain, 94, 173-190. 290. Edited by E. R. Ramey and D. S. O'Doherty. Hoeber: Daly, D. D. (1958). Uncinate fits. Neurology, 8, 250-260. New York. Daly, D. D., and Mulder, D. W. (1957). Gelastic epilepsy. Smythies, J. R. (1970). Brain Mechanisms and Behaviouir. 2nd Neutrology, 7, 189-192. Ed. Blackwell: Oxford. Davison, C., and Kelman, H. (1939). Pathologic laughing Terzian, H., and Ore. G. Dalle (1955). Syndrome of Kluver and crying. Archives of Neurology and Psychiatry, 42, 595- and Bucy reproduced in man by bilateral removal of the 643. temporal lobes. Neutrology, 5, 373-380. Dott, N. M. (1938). Surgical aspects of the hypothalamus. Weil, A. A. (1959). Ictal emotions occurring in temporal lobe In The Hypothalamuis, Morphological, Functional, Clinical dysfunction. Archives of Neurology, 1, 87-97. and Surgical Aspects, pp. 179-181. Edited by W. E. Clark, Weil, A. A., Nosik, W. A., and Demmy, N. (1958). Electro- on September 26, 2021 by Beattie, J., Le Gros, G. Riddoch, and N. M. Dott. encephalographic correlation of laughing fits. Amizericani Oliver and Boyd: Edinburgh. Jolurnal of Medical Science, 235, 301-308. Druckman, R., and Chao, D. (1957). Laughter in epilepsy. Williams, D. (1956). The structure of emotions reflected in Neuirology, 7, 26-36. epileptic experiences. Brain, 79, 29-67. Fere, Ch. (1903). Le fou rire prodromique. Revtue Neltrolo- Wood, M. W., Svien, H. J., and Daly, D. (1958). Involuntary gique, 11, 353-358. laughter. Proceedings of the Mayo Clinic, 33, 266-275.