Researchers at Stony Brook University have identified a previously unknown brain circuit potentially involved in obsessive-compulsive disorder (OCD), which may lead to more targeted treatments for the condition. OCD, known for its distressing thoughts and repetitive behaviors, is typically treated through psychotherapy and medication.

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The study, led by Joshua L. Plotkin, PhD, and published in the journal Neuron on September 28, 2026, utilized a murine model to investigate brain activity. While mouse brains differ from human brains, they share similar structures and organizational principles.

The research focused on the amygdala, responsible for processing emotions like fear and anxiety, and the dorsolateral striatum (DLS), crucial for habitual behaviors. The team discovered a direct connection between the amygdala and the DLS, previously unrecognized in earlier studies.

Using advanced imaging techniques, the researchers were able to map this connection at the synapse level. First author Zachary Hobel found that this connection, though small, significantly influences the DLS and enhances synaptic plasticity related to sensory behaviors. The study demonstrated that stimulating the amygdala's connection to the DLS amplified sensory-induced actions in mice, affecting their responses long after the stimulation ceased.

For instance, when water was dropped on a mouse's nose, it would groom itself, but stimulation during this action led to prolonged grooming behavior, even after the stimulation stopped.

The findings showed that in a mouse model of OCD, the amygdala-DLS circuit was overly active and poorly regulated. Chronic inhibition of the amygdala prevented OCD-like behaviors, indicating a clear mechanism linking emotional experiences to compulsive behaviors.

Dr. Plotkin emphasized that while the findings provide significant insights into OCD's underlying mechanisms, the precise neuronal connections affected by current treatments remain unclear. However, this research offers new avenues for identifying specific targets for OCD therapies.

The study included collaboration with experts from the National Institutes of Health and the University of Iowa, with funding from multiple federal agencies, including the National Institute of Neurological Disorders and Stroke and the National Institute of Mental Health.