Sleep, Memory & Addiction

In order to permanently store memories, we need to consolidate them after acquiring them. In the past decades, sleep has received more and more attention as a state where such consolidation processes take place (Diekelmann & Born, 2011). Memory traces encoded during wake are replayed during sleep, that is, neurons that were active when a specific memory was made fire again (Wilson & McNaughton, 1994). However, not all the memories we make enter long-term memory – some are more important than others. During sleep, relevant memories are preferentially consolidated, e.g. emotional ones (Wagner et al., 2001; but see Lipinska et al., 2019), those associated with reward (Fischer & Born, 2009; Igloi et al., 2015) or memories that we expect to need in the future (van Dongen et al., 2012; Wilhelm et al., 2011; but see Wamsley et al., 2016).

Dopaminergic neuromodulation plays an important rule in determining which memories enter long-term memory and which memories are replayed during sleep (Feld & Born, 2019; Lisman & Grace, 2005; Perogamvros & Schwartz, 2012). This is why we hypothesise that when the dopaminergic reward system is altered, such as in alcohol use disorder (Blum et al., 2000; Everitt & Robbins, 2013; Hyman, Malenka & Nestler, 2006), sleep could contribute to the formation or maintenance of the addiction. To test this, we compare sleep-dependent reward consolidation between alcohol use disorder patients and healthy controls. If we identify any differences, this will tell us more about the reward system’s role in memory consolidation during sleep. Importantly, this would enable us to use sleep-based interventions to aid the treatment of substance abuse disorders.

Open Science

Already before starting my PhD, I became interested in the open science movement. I am happy that the group I work in is implementing practices that make our work more reproducible, more accessible and less prone to errors. We work with large sample sizes and our projects are currently being prepared for submission as registered reports, so the methods and hypotheses can be reviewed before any data is collected. We prepare our manuscripts in R Markdown and use GitHub for version control and to code collaboratively and in an organised manner.