Each half of the brain has one nucleus accumbens. It is located where the head of the caudate and the anterior portion of the putamen meet just lateral to the septum pellucidum. The nucleus accumbens and the olfactory tubercle collectively form the ventral striatum, which is part of the basal ganglia.
The nucleus accumbens can be divided into two structures -- the nucleus accumbens core and the nucleus accumbens shell. These structures have different morphology and function.
Dopaminergic input from the VTA is thought to modulate the activity of neurons within the nucleus accumbens. These terminals are also the site of action of highly-addictive drugs such as cocaine and amphetamine, which cause a manifold increase in dopamine levels in the nucleus accumbens. In addition to cocaine and amphetamine, almost every recreational drug has been shown to increase dopamine levels in the nucleus accumbens.
Although the nucleus accumbens has traditionally been studied for its role in addiction, it plays an equal role in processing many rewards such as food and sex. A recent study found that it is involved in the regulation of emotions induced by music , perhaps consequent to its role in mediating dopamine release. It also has roles in timing, and has long been considered to be the limbic-motor interface (Mogensen).
Additionally, in July 2007, researcher Jon-Kar Zubieta published findings that the nucleus accumbus is central to the machinery of the placebo effect. He and his colleagues found that people who showed greater activation of the NAcc during a reward-expectation task also showed a greater anticipation of effectiveness of a placebo.
Neural Mechanisms of Spatial Working Memory: Contributions of the Dorsolateral Prefrontal Cortex and the Thalamic Mediodorsal Nucleus
Dec 01, 2004; The dorsolateral prefrontal cortex (DLPFC) has been known to play an important role in working memory. Neurophysiological studies...