O012 The Impact of Sleep Restriction on Reward learning in Healthy Adults

Sleep disruption can lead to enhanced reactivity towards pleasurable stimuli and impaired discrimination between rewarding and punishing cues. Thus, sleep may play a mechanistic role in the development and exacerbation of pathological reward-related behaviours (e.g., gambling, substance use, etc.). The study aimed to explore the impact of sleep restriction on reward processing. Involving a 7-night at-home sleep monitoring protocol, participants were randomly assigned an experimental condition: sleep restriction (5-hr time in bed/night; SR) or well-rested (9-hr/night; WR). Adherence to the prescribed sleep schedules was assessed daily. On the eighth day participants completed a battery of reward- learning tasks, 2-hrs post-habitual wake. Participants were healthy adults (n = 45, mean age = 25.4 yrs, 64% female). Total sleep time for the SR group (n = 18) was 297.4 mins, whilst the WR was 485.8 mins (n = 27). For the probabilistic reward task, response bias (RB) did not significantly differ between the SR and WR groups during the overall task (p = 0.28), or during blocks one (p = 0.26) or two (p = 0.90). However, at block three, the SR group showed higher RB as compared to the WR group (p = 0.03), indicating SR participants exhibited a systematic preference for the frequently rewarded cues, relative to the WR group. These preliminary results suggest initial reward responsiveness is not impacted by SR, but over time SR may produce heightened sensitivity to rewarding cues. This may indicate a role for sleep disruption in the maintenance of maladaptive appetitive behaviours.