NMDA receptor-dependent plasticity in the nucleus accumbens connects reward-predictive cues to approach responses.

Learning associations between environmental cues and rewards is a fundamental adaptive function. Via such learning, reward-predictive cues come to activate approach to locations where reward is available. The nucleus accumbens (NAc) is essential for cued approach behavior in trained subjects, and cue-evoked excitations in NAc neurons are critical for the expression of this behavior.

The role of the nucleus accumbens in learned approach behavior diminishes with training.

Nucleus accumbens dopamine plays a key role in reward-directed approach. Past findings suggest that dopamine's role in the expression of learned behavior diminishes with extended training. However, little is known about the central substrates that mediate the shift to dopamine-independent reward approach.

Expanding the role of striatal cholinergic interneurons and the midbrain dopamine system in appetitive instrumental conditioning.

The basal ganglia are a collection of subcortical nuclei thought to underlie a wide variety of vertebrate behavior. Although a great deal is known about the functional and physiological properties of the basal ganglia, relatively few models have been formally developed that have been tested against both behavioral and physiological data. Our previous work (Ashby FG, Crossley MJ.

Effects of varying reinforcement probability on pavlovian approach behavior and ultrasonic vocalizations in rats.

Long Evans rats (n=32) were trained for 2 weeks to respond to an auditory conditioned stimulus (CS) which signaled the delivery of a 20% sucrose unconditioned stimulus (US) with varying probabilities. Animals were randomly assigned to 1 of 4 groups. In the control groups, the CS signaled sucrose delivery with equal probabilities across two weeks, at 100% (Group 100-100) and 25% (Group 25-25) respectively.