Research Bursary Program

Supervisor Project Proposal (Summer 2014)

Supervisor Last Name: Boivin / Supervisor First Name: Diane B
McGill Dept/School: Psychiatry
Faculty Professor (Full, Associate or Assistant): Full
Email: / Phone No. (optional): 514-761-6131 ext 2397
Research Field: Human chronobiology / Proposal No. (1 or 2): 2
Research Location (McGill or affiliated institution): Douglas Mental Health University Institute
Ethics approval will be required for proposed project (Yes/No): No
Proposed project will involve chart reviews (Yes/No): Yes

Project Title(maximum 1 line):

Circadian variation of sleep and alertness in non-24-hour sleep-wake disorder

Hypothesis/Question to be Addressed(maximum 4 lines):

The non-24 hour sleep-wake (or hypernychthemeral) syndrome is the most severe circadian rhythm disorder, characterized by a lack of entrainment of the endogenous circadian pacemaker to the 24-hour day. While frequently seen in blind patients, this condition is rather uncommon in sighted subjects and we hypothesize that it is linked to a disrupted control by the endogenous circadian system of sleep propensity.

Specific Aims(maximum 10 lines):

It is well established that most physiological, hormonal, and behavioral rhythms have an endogenous circadian component that is regulated by an endogenous circadian pacemaker, located in the suprachiasmatic nucleus (SCN) of the hypothalamus. This so called “circadian clock” and the rhythms it controls are entrained to their environment by the cyclic exposure to synchronizers, the most powerful of which is the light-dark cycle. When the process of circadian entrainment to the environment is impaired, the endogenous circadian clock free-runs according to its own internal day length which results in an abnormal sleep schedule and a tendency to delay bedtime from one day to the other. There is evidence suggesting that individuals who suffer from delayed sleep phase disorder (which are extreme evening types) and hypernychthemeral syndrome, have an abnormal regulation of sleep propensity. As the hypernychthemeral syndrome is a relatively uncommon disorder in sighted patients, it is proposed to plan in-depth exploration of identified cases in highly controlled laboratory conditions.

Role of Student(maximum 15 lines):

This project represents an excellent opportunity for an independent and responsible student to enroll in a research project and to study at the forefront of our current knowledge of the human circadian physiology. The student will receive a comprehensive training in the laboratory techniques associated with the study of human sleep and circadian rhythms. This includes administration of tests, care of samples, data collection and follow-up of subjects. To gain hands-on experience, the student will participate actively to on-going laboratory experiments with different subjects studied in our time isolation laboratory. Following the review of the relevant literature, s/he will participate, in collaboration with a postdoctoral fellow, to the analysis and interpretation of data collected. This will involve the analysis of the clinical research file of neurological patients who underwent a circadian investigation, as well as the analysis of wrist-actigraphy recordings, sleep-wake log, subjective alertness, subjective mood, psychomotor vigilance, sleep recordings and the circadian rhythm of melatonin and cortisol secretion. Patients and healthy controls will spend 4-5 days in one of our time-isolation rooms. During this period, after remaining on their habitual schedule on the first day, the participants will go under a 48-h specific ultradian sleep-wake cycle which will end with an ad libitum sleep episode. Various physiological, hormonal, and behavioral data will be collected, analyzed and compared between the patients and healthy controls. These studies have clinical implications for patients suffering from a variety of sleep and circadian rhythm disorders.