In the current study, the researchers obtained their data on both hypocretin and MCH directly from the brains of eight patients who were being treated at Ronald Reagan UCLA Medical Center for intractable epilepsy. The patients had been implanted with intracranial depth electrodes by Dr. Itzhak Fried, a UCLA professor of neurosurgery and psychiatry and a co-author of the study, to identify seizure foci for potential surgical treatment. The location of electrodes was based solely on clinical criteria. The researchers, with the patients' consent, used these same electrodes to "piggyback" their research. A membrane similar to that used for kidney dialysis and a very sensitive radioimmunoassay procedure were used to measure the release of hypocretin and MCH.
The patients were recorded while they watched television; engaged in social interactions such as talking to physicians, nursing staff or family; ate; underwent various clinical manipulations; and experienced sleepwake transitions. Notes of activities were made throughout the study every 15 minutes in synchrony with a 15-minute microdialysis sample collection by a researcher in the patients' rooms.
The subjects rated their moods and attitudes on a questionnaire, which was administered every hour during waking.
The researchers found that hypocretin levels were not linked to arousal in general but were maximized during positive emotions, anger, social interactions and awakening. In contras
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University of California - Los Angeles