The nucleus accumbens (NAcc) is a small but powerful structure in the brain’s basal forebrain. It acts as a hub for processing reward, motivation, and pleasure.
Think of it as the brain’s motivational switchboard—it helps us decide what feels good, what’s worth pursuing, and what behaviors to repeat.
Where Is It Located?
The nucleus accumbens is located deep in the brain, near the front, in a region called the ventral striatum.
Each hemisphere of the brain has its own nucleus accumbens. It sits where the caudate and putamen meet, close to the prefrontal cortex and the brain’s dopamine pathways.
This structure has two major parts:
- Core: Connects to areas involved in movement and action.
- Shell: Connects to emotional and limbic regions, processing feelings and motivation.
Together, these regions help transform motivation into action.
Functions
The nucleus accumbens plays a key role in:
- Reward and pleasure: It lights up when we experience something enjoyable—like tasty food, music, or praise.
- Reinforcement learning: It helps us learn which behaviors lead to rewards and encourages us to repeat them.
- Motivation and decision-making: It influences how strongly we pursue goals or avoid risks.
Much of this activity depends on dopamine, a neurotransmitter associated with motivation, novelty, and learning.
When dopamine is released from the ventral tegmental area (VTA), it floods the nucleus accumbens, encouraging us to seek more of whatever triggered the response.
Beyond Rewards: A Complex Role
While the nucleus accumbens is best known for processing rewards, it’s also involved in other functions:
- Responding to both positive and negative stimuli
- Impulsivity and risk-taking
- Locomotion and movement planning
- Sexual motivation and social bonding
- Linking memories and emotions to experiences
Its connections with the hippocampus and amygdala allow it to tag emotional and contextual meaning to rewards or threats.
How Does It Affect Mental Health?
Because the nucleus accumbens is central to pleasure and motivation, disruptions in its function are linked to several psychological and neurological conditions:
Addiction
Drugs like cocaine, heroin, and even nicotine or alcohol trigger strong dopamine surges in the NAcc.
Over time, this rewires the brain’s reward system, making people crave substances and lose interest in everyday rewards. This helps explain why addiction is so hard to break.
Depression and Mood Disorders
People with depression often show reduced NAcc activity (Heller et al., 2009). They may find it harder to enjoy life, feel motivated, or pursue rewarding activities.
Studies using deep brain stimulation targeting the NAcc have shown promising results in treatment-resistant depression (Bewernick et al., 2010).
Anxiety and OCD
The nucleus accumbens connects closely with the amygdala, a region involved in fear and anxiety.
Dysregulation here may contribute to anxiety disorders and obsessive-compulsive disorder (OCD). Deep brain stimulation of the NAcc has been used to reduce OCD symptoms (Denys et al., 2010).
Parkinson’s and Alzheimer’s Disease
Apathy in Parkinson’s disease and motivational issues in Alzheimer’s have been linked to atrophy or dopamine disruption in the NAcc (Carriere et al., 2014).
These findings point to its broader role in goal-directed behavior and cognitive processing.
FAQs
What happens if the nucleus accumbens is damaged?
Damage or dysfunction in the nucleus accumbens can lead to problems with motivation, reward processing, and mood regulation.
This may contribute to conditions like depression, apathy, addiction, or even chronic pain sensitivity.
Is the nucleus accumbens involved in learning or memory?
Yes. It helps form associations between experiences and their emotional or motivational value—essential for learning from rewards or punishments.
Is the nucleus accumbens part of the limbic system or basal ganglia?
It’s part of both. Anatomically, it’s located in the basal ganglia, but functionally it connects closely with the limbic system—linking emotion with action.
References
Berns, G. S., McClure, S. M., Pagnoni, G., & Montague, P. R. (2001). Predictability modulates human brain response to reward. Journal of neuroscience, 21(8), 2793-2798.
Bewernick, B. H., Hurlemann, R., Matusch, A., Kayser, S., Grubert, C., Hadrysiewicz, B., Axmacher, N., Lemke, M., Cooper-Mahkorn, D., Cohen, M. X., Brockmann, H., Lenartz, D., Sturm, V. & Schlaepfer, T. E. (2010). Nucleus accumbens deep brain stimulation decreases ratings of depression and anxiety in treatment-resistant depression. Biological psychiatry, 67(2), 110-116.
Carriere, N., Besson, P., Dujardin, K., Duhamel, A., Defebvre, L., Delmaire, C., & Devos, D. (2014). Apathy in Parkinson’s disease is associated with nucleus accumbens atrophy: a magnetic resonance imaging shape analysis. Movement disorders, 29(7), 897-903.
Denys, D., Mantione, M., Figee, M., Van Den Munckhof, P., Koerselman, F., Westenberg, H., Bosch, A. & Schuurman, R. (2010). Deep brain stimulation of the nucleus accumbens for treatment-refractory obsessive-compulsive disorder. Archives of general psychiatry, 67(10), 1061-1068.
Du, K., Lu, W., Sun, Y., Feng, J., & Wang, J. H. (2019). mRNA and miRNA profiles in the nucleus accumbens are related to fear memory and anxiety induced by physical or psychological stress. Journal of psychiatric research, 118, 44-65.
Heller, A. S., Johnstone, T., Shackman, A. J., Light, S. N., Peterson, M. J., Kolden, G. G., Kalin, N. H. & Davidson, R. J. (2009). Reduced capacity to sustain positive emotion in major depression reflects diminished maintenance of fronto-striatal brain activation. Proceedings of the National Academy of Sciences, 106(52), 22445-22450.
Knutson, B., Adams, C. M., Fong, G. W., & Hommer, D. (2001). Anticipation of increasing monetary reward selectively recruits nucleus accumbens. Journal of Neuroscience, 21(16), RC159-RC159.
Makary, M. M., Polosecki, P., Cecchi, G. A., DeAraujo, I. E., Barron, D. S., Constable, T. R., Whang, P. G., Thomas, D. A., Mowafi, H., Small, D. M. & Geha, P. (2020). Loss of nucleus accumbens low-frequency fluctuations is a signature of chronic pain. Proceedings of the National Academy of Sciences, 117(18), 10015-10023.
Mavridis, I. (2015). The role of the nucleus accumbens in psychiatric disorders. Psychiatrike= Psychiatriki, 25(4), 282-294.
Mogenson, G. J., Jones, D. L., & Yim, C. Y. (1980). From motivation to action: functional interface between the limbic system and the motor system. Progress in neurobiology, 14(2-3), 69-97.
Neuroscientifically Challenged. (2014, June 13). KNOW YOUR BRAIN: NUCLEUS ACCUMBENS. https://neuroscientificallychallenged.com/posts/know-your-brain-nucleus-accumbens
Nobili, A., Latagliata, E. C., Viscomi, M. T., Cavallucci, V., Cutuli, D., Giacovazzo, G., Krashia, P., Romana Rizzo, F., Marino, R., Federici, M., De Bartolo, P., Aversa, D., Concetta Dell’Acqua, M., Cordella, A., Sancandi, M., Keller, F., Petrosini, L., Puglisi-Allegra, S., Biagio Mercuri, N., Coccurello, R., Berretta, N. & D’Amelio, M. (2017). Dopamine neuronal loss contributes to memory and reward dysfunction in a model of Alzheimer’s disease. Nature communications, 8(1), 1-14.
Salgado, S., & Kaplitt, M. G. (2015). The nucleus accumbens: a comprehensive review. Stereotactic and functional neurosurgery, 93(2), 75-93.
Volman, S. F., Lammel, S., Margolis, E. B., Kim, Y., Richard, J. M., Roitman, M. F., & Lobo, M. K. (2013). New insights into the specificity and plasticity of reward and aversion encoding in the mesolimbic system. Journal of Neuroscience, 33(45), 17569-17576. https://doi.org/10.1523/JNEUROSCI.3250-13.2013
Wise, R. A. (1982). Neuroleptics and operant behavior: the anhedonia hypothesis. Behavioral and brain sciences, 5(1), 39-53.
Zabek, M., Sobstyl, M., Koziara, H., & Dzierzecki, S. (2008). Deep brain stimulation of the right nucleus accumbens in a patient with Tourette syndrome. Case report. Neurologia i neurochirurgia polska, 42(6), 554-559.
