Feld G. DFG - Deutsche Forschungsgemeinschaft GZ: FE 1617/2-1: Advancing the treatment and prevention of addiction by understanding sleep’s basic role. 04/2019-04/2021.
Most people have a “bad habit” they would like to change. This could be smoking cigarettes, drinking alcohol, exercising too little, eating unhealthy or anything that they want to do, but that negatively impacts their wellbeing and induces regret. Wouldn’t it be great to change this unwanted behaviour during sleep? The main goal of this research project is to identify how sleep maintains addiction and to use this knowledge to change it. The brain’s reward centres can be viewed as the neurophysiological basis that emphasizes one behaviour over another. Recently, in healthy young participants, sleep has been shown to interact with these reward signals that strengthen rewarded information more strongly than unrewarded information. The present research aims to show that, during learning, mesolimbic reward signals are bound to hippocampal memory representations of events and actions that led to rewards and that, during subsequent sleep, replay specifically enhances such tagged representations over non-rewarded events and actions. Not all long-term goals can be reached by prioritizing only short-term goals, therefore, animals evolved more complex reinforcement processes that can enhance uncomfortable or even dangerous actions to gain an adaptive advantage in the future. In animals, this powerful force stabilizing instrumental behaviour mostly leads to beneficial pleasurable outcomes, such as increased probabilities of finding food or mates. In modern time humans, it can just as easily drive unhealthy habits and, more dangerously, this type of learning can become the basis of addictive behaviour such as drug abuse and gambling that the person no longer views as pleasurable but still cannot resist. The unconscious sleep phase opens a potential target for interventions that ameliorate or even erase this maladaptive wanting by replacing or redirecting the endogenous tags. Ultimately, the current project proposes linking sleep and addiction memory research in clinical settings to enhance the malleability of these hard to change behaviours.