NAcc

Nacc is commonly used to refer to the nucleus accumbens, a brain structure in the ventral striatum involved in reward and motivation. It is located in the basal forebrain, at the border between the caudate nucleus and putamen, rostral to the ventral pallidum. The nucleus accumbens comprises two major subregions, the core and the shell, which differ in inputs, outputs, and function.

Anatomy and microstructure: The nucleus accumbens is densely populated by GABAergic medium spiny neurons. It receives dopaminergic input from the ventral tegmental area and glutamatergic input from the prefrontal cortex, amygdala, and hippocampus. Efferent projections go to the ventral pallidum and other basal forebrain areas, forming part of the circuitry that links limbic information with motor output. The core and shell exhibit distinct connectivity patterns that contribute to differences in cue processing and motivational bias.

Function and roles: The nucleus accumbens participates in reward processing, reinforcement learning, and goal-directed motivation. It codes aspects of reward prediction error and incentive salience, influencing approach behavior. It is activated by natural rewards and drugs of abuse, and dysregulation of its activity is associated with addiction, mood disorders, and schizophrenia in various studies.

Clinical relevance: Altered NAcc signaling is a focus in addiction research and a target for neuromodulation strategies. Deep brain stimulation and other approaches targeting the nucleus accumbens have been explored for treatment-resistant obsessive-compulsive disorder and major depressive disorder, with mixed results. Pharmacological interventions often aim to modulate dopaminergic, GABAergic, or glutamatergic signaling within this region.

Alternative meaning: In biomedical research, NACC is the acronym for the National Alzheimer’s Coordinating Center, a program established to coordinate Alzheimer’s disease data collection across participating sites, including the Uniform Data Set and biospecimen resources.