The role of ethanol and neuroanatomical regions in sensitivity to delay and sensitivity to magnitude of reward

Delay discounting—the preference for smaller, sooner rewards over larger, later ones—is increased by acute ethanol, but the underlying mechanisms remain unclear. This dissertation used two behavioral tasks in male Long Evans rats to separately assess sensitivity to delay and magnitude, and examined the effects of ethanol and temporary inactivation of the nucleus accumbens core (AcbC) and lateral orbitofrontal cortex (lOFC). Neither ethanol nor brain region inactivation altered sensitivity to delay or magnitude, but AcbC inactivation significantly reduced delay discounting, particularly in rats with low baseline discounting. Findings reveal task differences, a potential link between delay sensitivity and ethanol’s behavioral effects, and a novel role for AcbC in regulating impulsive choice.