Grant: Master's Award: Canada Graduate Scholarships

Based on the neural oscillation, muscle activity and movement of eyes, sleep is divided into two major components: rapid eye movement sleep (REM) and non-rapid eye movement (NREM). NREM is further divided into three distinct stages based on the frequency and amplitude of neural oscillation. In addition, there exist micro-events specific to each stage, which facilitates the detection of each stage. One of these micro-events is spindles. Two of the prominent features of NREM sleep are spindles and slow wave activity. A growing number of human neuroscience studies demonstrate that sleep spindles and slow wave activity play an essential role in different cognitive processes. On the other hand, it has been shown that the neural oscillation and electroencephalography (EEG) features of sleep remain unchanged within an individual from one night to the next. However, there is evidence that the amount of sleep spindle and slow wave activity differ between individuals. It is unclear what exactly causes these inter-individual differences. One recent study attempted to discover if macroscopic differences of the volume of grey matter in humans contribute to these inter-individual differences. However, the relationship of these EEG phasic traits of NREM sleep and other anatomical metrics of the brain, such as the volume of white matter fiber tracts projecting from the thalamus to the neocortex is yet to be investigated. Our study's aim is to utilize neuroimaging and EEG technique to investigate the relation of the volume of white matter fiber tracts projected from thalamus to the neocortex in human and examine whether it can explain the inter-individual differences of spindles and slow wave activity in NREM sleep.