Tweaking dreams: non-invasive modulation of the level and content of mental activity during sleep

ongoing

Sleep and wakefulness have traditionally been regarded as two mutually exclusive states characterized by differences in consciousness and responsiveness to the environment. However, the last two decades of research have demonstrated that sleep is actually a locally regulated phenomenon and that cortical islands of sleep- and wake-like activity can often coexist across distinct brain areas. Intriguingly, this mosaic of activity is also directly related to the presence and content of mental activity during sleep. In line with this, many sleep disorders, including insomnia and arousal disorders, are associated with significant local alterations in the balance between wake- and sleep-like activity. In spite of these considerations, the classical view of sleep as a uniform global state is still dominant in both basic and clinical research. Moreover, it remains unclear whether the occurrence of local wake-like activity is related to specific physiological functions of sleep. The objective of this project is to progress towards a deep understanding of the mechanisms that regulate sleep at a local level through the exploitation of known properties of the thalamocortical system. At the core of the proposal is the idea that particular sensory-stimulation protocols may allow to directly modulate sleep intensity in a local, region-specific manner. Such approaches could be used to non-invasively perturbate regional sleep-related brain activity, thus allowing to investigate the causal consequences on sleep mentation, subjective sleep quality and sleep-related functions, including learning and memory. Of note, the same approaches could also find application in counteracting alterations of local sleep regulation in pathological conditions. Knowledge gathered within the project could yield potential breakthroughs in numerous key applications of tremendous clinical, social and economic interest including treatment of sleep disorders and prevention of sleepiness-related accidents.