Cerebral MRI During Sleep

Recent studies in animal models have suggested a critical role for cerebrospinal fluid (CSF) / Interstitial fluid (ISF) flux through cerebral parenchyma for removal of byproducts of cellular metabolism and hence in maintaining the health of the brain. It remains unknown to what extent these phenomena exist in the human brain. A key challenge in this work is to make non-invasive and reproducible measurements of the cerebral microenvironment in humans. For these studies, the investigators have implemented a suite of MRI measurements to track physiological changes in the brain during sleep. This exploratory work aims to establish the sensitivity and reproducibility of MRI as a non-invasive neuroimaging assessment of cerebral changes during natural sleep and sedation. The long term goal of this work is to use MRI as an imaging biomarker to assess the cerebral response to normal versus disordered sleep in patients.

Our specific aims will address the following questions:

Aim 1: How sensitive are MRI metrics for determining changes in the brain during sleep?

Aim 2: How reproducible are MRI metrics during sleep and during sedation?

The investigators will recruit 12 normal adult subjects for this study (consecutive respondees to recruitment adverts). The investigators will make regional MRI measurements during onset, maintenance and waking from stage N2 sleep. From these the investigators will characterize which MRI metrics are most sensitive to changes in the cerebral environment, and how these vary for different cerebral regions.