MAIN TEXT
Individuals differ widely in their reward- and drug-craving behaviors.
One reason for these differences involves sleep. Sleep disturbances lead
to an increased risk of substance use disorders and relapse in some, but
not all, individuals. There is considerable individual variation in the
cognitive and emotional responses to sleep deprivation (SD) and how SD
alters the motivation for food or drug reward. The precise neural
circuits explaining this individual variation remain poorly understood.
While animal studies have examined the general impact of sleep on reward
circuitry, few have addressed the role of individual differences in the
effects of altered sleep. There does, however, exist a robust
preclinical rodent model of individual differences in reward-seeking
behavior. In this model, only some rats show heightened cue-induced
dopamine activity, resulting in hyper-sensitivity to the motivational
effects of cues. This subset of rats also shows many of the key
behavioral traits associated with addiction, including increased
impulsivity and poor attentional control. Other rats do not show these
addiction-related tendencies, making this an ideal model system in which
to study the relationship between altered sleep and individually
distinct reward-seeking behaviors. In this review, we support this
argument by describing how the limbic neural circuits responsible for
individual differences in incentive motivation closely overlap with
those involved in sleep-wake regulation. Consideration of these
individual differences in preclinical models would improve our
understanding of how sleep interacts with motivational systems, and why
sleep deprivation contributes to reward-seeking behavior and addiction
in only a select group of individuals.