New Findings Reveal Surprising Role of the Cerebellum in Reward, Social Behaviors

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A new study in rodents has shown that the brain’s cerebellum—known to play a role in motor coordination—also helps control the brain’s reward circuitry. Researchers found a direct neural connection from the cerebellum to the ventral tegmental area (VTA) of the brain, which is an area long known to be involved in reward processing and encoding. These findings, published in Science, demonstrate for the first time that the brain’s cerebellum plays a role in controlling reward and social preference behavior and sheds new light on the brain circuits critical to the affective and social dysfunction seen across multiple psychiatric disorders. The research was funded by NIMH.

“This type of research is fundamental to deepening our understanding of how brain circuit activity relates to mental illnesses,” said NIMH director Dr. Joshua Gordon. “Findings like the ones described in this paper help us learn more about how the brain works, a key first step on the path towards developing new treatments.”

The cerebellum plays a well-recognized role in the coordination and regulation of motor activity. However, research has also suggested that this brain area contributes to a host of non-motor functions. For example, abnormalities in the cerebellum have been linked to autism, schizophrenia and substance use disorders and brain activation in the cerebellum has been linked to motivation, social and emotional behaviors and reward learning, each of which can be disrupted in psychiatric disorders. 

These earlier findings led Dr. Kamran Khodakhah of Albert Einstein College of Medicine and colleagues to wonder if there was a direct connection between the cerebellum and the VTA—a brain structure involved in controlling reward and motivational behaviors. To examine this, the researchers used a technique called optogenetics, in which the neurons of animals are genetically modified, so they can be controlled using pulses of light. The researchers used this technique in mice, activating neurons in the cerebellum that connected to the VTA. The researchers found that activating the cerebellar neurons led to increased activation in the VTA of mice, indicating a working connection between these two brain structures.