Delphine Oudiette

Sleep disturbances are a core symptom of numerous societal health issues such as depression, Parkinson’s disease or Alzheimer’s disease. This suggests that sleep has a crucial role in our global cognitive functioning, but its exact functions and underlying mechanisms are still poorly understood. Our overarching goals are to unravel why we sleep and dream as well as to elucidate the neural mechanisms underlying the cognitive functions of sleep and how they are altered in neurological disorders.

These questions are challenging for researchers because they have no access to the mental and cognitive processes happening during sleep and no experimental control over them. For example, it is difficult to tease apart one specific sleep-related cognitive process by solely linking cognitive performance during wake with brain activity measured during an entire sleep period. Similarly, subjective experiences occurring during sleep (i.e. dreams) are typically studied indirectly, through reports of dream memories collected when people wake up, yielding numerous biases (e.g. forgetting, description difficulty).
In our past research, we have looked for ways to ‘see through the invisible’ to unravel why humans sleep and dream. To do so we are studying hybrid states between wake and sleep (e.g. sleepwalking, lucid dreaming, sleep onset period), the presence of wake features in these global states of sleep opening a portal into the sleeper’s mind. We are investigating these states by combining several approaches: i) neurophysiological recordings (video-polysomnography), ii) analysis of behaviors during sleep (either spontaneous or in reaction to stimuli), iii) experience sampling (e.g. dream reports), iv) cognitive tasks probing various functions (i.e. creativity, memory, attention), and v) innovative approaches in cognitive sciences (gesture recognition algorithm, graph theory for semantic networks, targeted memory reactivation).