| Klüver-Bucy syndrome | |
|---|---|
| Specialty | Psychiatry,neurology,urology  |
Klüver–Bucy syndrome is asyndrome resulting fromlesions of themedial temporal lobe, particularlyBrodmann area 38,[1] causingcompulsive eating,hypersexuality, a compulsive need to insert inappropriate objects in the mouth (hyperorality),visual agnosia, anddocility. Klüver–Bucy syndrome is more commonly found inrhesus monkeys, where the condition was first documented, than in humans.[2] The underlying pathology of the syndrome is still controversial, withMuller theory and a theory by Norman Geschwind offering different explanations for the condition.[2] Treatment for Klüver–Bucy syndrome is usually with mood stabilizers, anti-psychotics, and anti-depressants.[3]
The list of symptoms generally include the following:
While this cluster of five syndromes is considered to be required by these three sources,[4][5][6] further symptoms are included or omitted in the diagnostic criteria depending on the authority. These include:
There are a few theories that attempt to explain the processes behind Klüver–Bucy syndrome and its symptoms. This topic still remains controversial, in part because complete Klüver–Bucy syndrome is rare in humans, particularly compared to monkeys.[2] Klüver–Bucy syndrome is thought to occur from damage to temporal sections of the limbic networks, which connect to other structures that regulate emotional behavior.[2]
Norman Geschwind's theory states that Klüver–Bucy syndrome is caused by disconnect syndrome (a condition of the brain where the two hemispheres develop separately, or at different rates), and that the initial contributor for this is blockage of visual input to the limbic circuit.[2]
Another theory, called Muller theory, attributes Klüver–Bucy syndrome to the disconnection of pathways used for emotional regulation and memory, such as those connecting the dorsomedial thalamus to the prefrontal cortex.[2] The medial temporal sections of the limbic system can be associated with more primitive functions, such as reproduction, food, and defense.[2] This can be seen in the symptoms of increased hypersexuality, hyperorality, and general aggression.[2]
As part of an investigation byHeinrich Klüver in the 1930s into the brain areas affected bymescaline, Klüver arranged to have the temporal lobes of a number ofrhesus monkeys bilaterally removed byPaul Bucy, a neurosurgeon.[7] Klüver did not find the expected impact in response to mescaline, but did observe a series of changes in the subject animals. The six points of difference that Klüver recorded werevisual agnosia, an increased tendency to explore items by mouth,hypermetamorphosis, dampening of emotional expression, altered sexual behavior, and differences in diet.[7] Klüver later discovered similar observations bySanger Brown andEdward Albert Sharpey-Schafer that had been published in 1881, and drew on these to substantiate his own observations.[7]
Monkeys in the Klüver-Bucy experiment evidently had normal vision and motor skills, but exhibited "psychic blindness" – what Rusiko Bourtchouladze described in 2004 as an inability to recognize "the emotional importance of events".[8] They did not display fear for items that would ordinarily frighten members of their species, they displayed an appetite for improper foods such as rocks or live rats, and they sought intercourse with unusual partners, including members of other species.[8] They became extremely interested in exploring items in their environment, and becameplacid when approached.[9]
Klüver–Bucy syndrome was first documented among certain humans who had experienced temporallobectomy in 1955 by H. Terzian and G.D. Ore.[10] It was first noted in a human withmeningoencephalitis in 1975 by Marlowe et al.[4][6] Klüver–Bucy syndrome can manifest after either of these (lobectomies can be medically required by such reasons as accidents ortumors), but may also appear in humans with acuteherpes simplex encephalitis or following astroke.[11] Underlying conditions contributing to the diagnosis of Klüver–Bucy syndrome includePick's disease,Alzheimer's disease,ischemia,anoxia, progressive subcorticalgliosis,Rett syndrome,porphyria, andcarbon monoxide poisoning, among others.[4]
It is rare for humans to manifest all of the identified symptoms of the syndrome; three or more are required for diagnosis.[4] Among humans, the most common symptoms include placidity, hyperorality, and dietary changes.[4] They may also present with aninability to recognize objects, or aninability to recognize faces, or othermemory disorders. Social neuroscience research shows that changes in the temporal lobe are commonly identified as a cause for hypersexuality, and other aberrant sexual behaviors.[12]
Klüver–Bucy syndrome has been shown to occur more in adults than in children.[13] In children, certain conditions such as herpes simplex encephalitis have the potential to manifest the syndrome.[13] Children exhibit many of the same symptoms as adults with Klüver–Bucy syndrome, but they display these symptoms in different ways than adults.[13] In children, hypersexuality as a symptom of Klüver–Bucy syndrome in is characterized by "frequent touching of genitals, intermittent pelvic thrusting movements, and rubbing of genitals on the bed while lying prone".[13] Observations of hypersexuality in children have been recorded primarily in children under the age of 4.[13] It is thought that since these behaviors have yet to be learned by children, that they display themselves in more ambiguous ways.[13] Depending on which underlying conditions lead to Klüver–Bucy syndrome, the pattern of symptoms observed can vary.[13]
Treatment for Klüver–Bucy syndrome focuses on controlling symptoms, as no current intervention can cure the condition.[14] Medications used to treat these symptoms includecarbamazepines, andleuprolide, which help reduce sexual behavior associated with Klüver–Bucy syndrome.[14] Carbamazepines have been shown to have the greatest effect when treating traumatic brain injury–derived Klüver–Bucy syndrome.[14] Other medications commonly utilized aremood stabilizers,antidepressants, and variousantipsychotic drugs.[14]
Klüver–Bucy syndrome was featured in the lead story of theRadiolab episode "Blame". The show looked into a man who developed Klüver–Bucy syndrome after his second neurosurgery for epilepsy.[15] The story was revisited byRadiolab in June 2017, augmented with further discussion with neuroscientist Dr.Robert Sapolsky, who addressed the syndrome and the associated legal significance of neurological defenses.[16]
In fiction, the Klüver–Bucy syndrome has been featured in theBlack Box episode "The Fear", the "Whistleblowers" episode ofBlue Bloods, the "Comfort's Overrated" episode ofRoyal Pains, and theCriminal Minds episode "Taboo".[citation needed]
Klüver-Bucy syndrome.
Klüver-Bucy syndrome.
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