Autumn School in Cognitive Neuroscience, University of Oxford (27–30 September 2004; Oxford, UK).

Delayed reinforcement is of interest from two perspectives. Firstly, when an animal works for a reinforcer, there is frequently a delay between its actions and their outcomes. How do animals succeed in bridging delays to reinforcement? Secondly, individuals vary in their ability to choose delayed rewards. Impulsive choice, one aspect of impulsivity, is characterized by an abnormally high preference for small, immediate rewards over larger delayed rewards, and can be a feature of attention-deficit/hyperactivity disorder (ADHD), addiction, and other neuropsychiatric disorders. Past neurochemical studies of impulsivity and impulsive choice will be discussed, together with recent neuroanatomical studies examining the effects of lesions to discrete limbic structures (including the nucleus accumbens core, medial prefrontal cortex, anterior cingulate cortex, basolateral amygdala, and orbitofrontal cortex) on behavioural tests requiring subjects to choose between two reinforcers when the larger one is delayed, or to learn on the basis of delayed reinforcement.