![cataplexy. cataplexy.](https://i.ytimg.com/vi/3KrdIPfCbsQ/maxresdefault.jpg)
Intriguingly, examination of the one patient experiencing the cataplectic attack showed dramatic reductions in hypothalamic activity. Results from the brain imaging analysis showed that although both groups activated regions associated with humor appreciation, the cataplexy group showed significantly more activity in the nucleus accumbens and hypothalamus as well as the right inferior frontal gyri when directly compared to the healthy control group. In summary, the narcolepsy-cataplexy patients rated the cartoons as being less humorous than the healthy control group. The analysis of a patient who experienced a prolonged cataplectic attack during scanning gave us the rare opportunity to examine both the non-cataplectic and cataplectic state. To test this prediction, we showed healthy subjects and cataplexy patients ( Table 1) humorous cartoons while they underwent functional magnetic resonance imaging (fMRI). We hypothesized that relative to healthy controls, narcolepsy-cataplexy individuals would show abnormal activity in brain regions associated with affect regulation and the hypocretin system - namely the hypothalamus. We sought to examine brain activation patterns in narcolepsy-cataplexy patients when shown humorous material. Hypocretin is expressed in a subset of neurons in the hypothalamus, a region associated with both emotion and sleep regulation. Interestingly, the key neurobiological marker of narcolepsy-cataplexy is the loss of hypocretin (otherwise known as orexin) which is highest (92.5%) in patients who are HLA-DQB1*0602 positive and report cataplectic attacks triggered by laughter. Together, these regions are thought to elicit the euphoric feeling associated with finding a joke humorous, –. These regions extend from the nucleus accumbens to other territories of the emotion network including the amygdala and hypothalamus. To date, several studies have shown that the neural systems associated with reward and emotion are engaged when subjects find cartoons humorous –. Although there seems to be a strong relationship between the brain regions associated with humor and cataplexy, it is not fully understood why humor causes debilitating muscle atonia in patients with narcolepsy-cataplexy. The symptoms of cataplexy can occasionally occur suddenly and without any obvious trigger, however, joking and humor-related laughter are considered the most common cause of cataplectic attacks.
![cataplexy. cataplexy.](https://i.pinimg.com/originals/7e/b9/79/7eb9791e36905b20029725e83aa67a4c.jpg)
antidepressant), the symptom is believed to be an equivalent of REM sleep atonia. Because it is associated with a loss of monosynaptic reflexes and is suppressed by drugs known to inhibit Rapid Eye Movement Sleep (REM) sleep (e.g. Symptoms of cataplexy can vary considerably, ranging from a mild sensation of flotation, day time sleepiness and abnormal rapid eye movement to complete muscle paralysis lasting up to several minutes. Cataplexy, a pathognomonic symptom of narcolepsy, has fascinated clinicians and researchers alike since its initial description in the late 1870s.