The full form of NAc is Nucleus Accumbens. It’s used on Medical ,Anatomy & Physiology in Worldwide

The nucleus accumbens (nucleus accumbens septi) is located in the rostral and ventral forebrain, where the head of the caudate nucleus and the putamen are continuous (see Fig. 26.4). These cells receive input from the amygdaloid complex (primarily via the ventral amygdalofugal pathway), from the hippocampal formation (through the precommissural fornix), and from cells of the bed nucleus of the stria terminalis (Fig. 31.9B). The ventral tegmental area also gives rise to ascending fibers that enter the nucleus accumbens via the medial forebrain bundle. In addition, amygdalofugal fibers traversing the stria terminalis also enter the nucleus accumbens.

Cells within the nucleus accumbens have receptors for a variety of neurotransmitters, including endogenous opiates. The nucleus accumbens may play an important role in behaviors related to addiction and chronic pain. Recent observations in addicted humans likewise reinforce the concept that the nucleus accumbens is a gratification site. These patients show marked binding of substances to cells in nucleus accumbens.

Efferent projections of the nucleus accumbens include fibers to the hypothalamus, nuclei of the brainstem, and the globus pallidus (Fig. 31.9B). Nucleus accumbens fibers to the last target represent an important route through which the limbic system may access the motor system.