The nucleus accumbens and learning and memory

Abstract

Recent research on the nucleus accumbens (NA) indicates that this brain region is involved in learning and memory processes in a way that is separable from its other well-known roles in behavior, such as motivation, reward, and locomotor activity. These findings have suggested that 1) the NA may be involved in declarative, or hippocampal formation-dependent learning and memory, and not in several other non-declarative forms of learning and memory, and 2) the NA may be selectively involved in certain stages of learning and memory. These characteristics suggest that the NA may be part of a larger striatal system which subserves acquisition and consolidation, but is not a site of long-term storage, of different forms of learning and memory.

Role of dopaminergic system in reactivity to spatial and non-spatial changes in mice

“…Consistently, it is worth noting that DA-depleting lesions in the striatum and hippocampus impair spatial learning (Whishaw and Dunnett 1985;Gasbarri et al 1996). Moreover, similar effects have been demonstrated after DA manipulation in the nucleus accumbens (Setlow 1997;Coccurello et al 1999). Our data also suggest that increased DA function strongly affects the emotional response to novelty by inducing neophobia, without affecting the cognitive performance required for spatial discrimination.…”

“…Systemic and focal administration of DA agonists in terminal areas, such as nucleus accumbens and striatum, enhances locomotor activity in laboratory animals, and these effects are blocked by selective lesion of these areas (Kelly et al 1975;Staton and Solomon 1984;Mele et al 1998). More recently, these areas have been related to cognitive functions, such as learning and memory (Taghzouti et al 1985;Annett et al 1989;Ploeger et al 1994;Floresco et al 1996Floresco et al , 1997Setlow 1997;Adriani et al 1998;Setlow and McGaugh 1998;Usiello et al 1998;Sargolini et al 1999). Manipulation of the DA system impairs performance in several tasks that involve the use of spatial information.…”

Co-activation of glutamate and dopamine receptors within the nucleus accumbens is required for spatial memory consolidation in mice

“…Recent findings suggest that the nucleus accumbens (Nac), a ventral extension of the basal ganglia, might play a relevant role in complex forms of learning that require a flexible use of sensory information (Schacter et al 1989;Maldonado-Irrizarry and Kelley 1995;Setlow 1997;Sargolini et al 1999Sargolini et al , 2003aRoullet et al 2001). In particular, it was demonstrated that manipulations of the nucleus accumbens induce deficits in the spatial version of the Morris water maze (Setlow and McGaugh 1998;Sargolini et al 2003a), in the radial maze (Gal et al 1997;Smith-Roe et al 1999), in a spatial version of the hole board (Maldonado-Irizarry and Kelley 1995), as well as in a task in which the animals are required to discriminate a spatial displacement of objects (Usiello et al 1998;Sargolini et al 1999;Roullet et al 2001).…”

Enhanced attention in rhesus monkeys as a common factor for the cognitive effects of drugs with abuse potential

“…Return projections from the nucleus accumbens via the thalamus to executive centers in the forebrain also complete a "cognitive" feedback loop in which components of memory, including long-term potentiation (which relates to issues of drug sensitization), are considered to be important for protracted elevated risk to renewed drugseeking behavior. Indeed, the cognitive aspects of drugs of abuse are of paramount importance in the understanding of reward systems and recidivism (Setlow 1997;Di Chiara et al 1999;Koob and Le Moal 2001). The significance of environmental associative processes in addiction are evidenced by recovered addicts' experience of cravings for the abused drug and even the return to drug use (recidivism) upon encountering drug-associated stimuli.…”