By Mariam Malik ‘22

The cerebellum, a five-centimeter wide part of the hindbrain, was initially thought of as having one major function: coordinating motor functions and balance. But new research on mice from the Albert Einstein College of Medicine in New York City shows that the remarkable cerebellar cortex may play a part in our social interactions as well.

Kamran Khodakhah and colleagues were aware that the cerebellum played an integral part in mental and social disorders, such as autism and schizophrenia, but did not know exactly how its possible connection with other regions of the brain played a role in the disorders. Khodakhah’s team predicted that, via a direct connection to the ventral tegmental area (VTA), the cerebellum is involved in motivated behavior. The VTA is a structure that functions in the understanding of reward and control of social conduct. To see if the two regions interacted in any way during a social situation, Khodakhah and his team saw that neurons originating in the cerebellum sent axons containing messages to cells in the VTA. The researchers were able to see this with unique molecular tools that sparked fluorescent proteins to light up specific cells. Furthermore, to understand the implications this connection between the two regions has on mice, the research team used optogenetics, or the use of light to control live cells in tissue, and in this case, to control the activity between the cerebellar neurons and the VTA. The mice felt good when these cells were activated, and researchers also found that the cells were activated when the mice socially communicated with each other, stimulating a feel-good response.

These new revelations of the connections between the cerebellum and social behavior may also explain some connections to autism. Pediatric neurologist and developmental biologist from Boston Children’s Hospital, Mustafa Sahin, has found some weaknesses in the cerebellar cells of patients with a distinct type of autism. The connection between the VTA and the cerebellum may certainly help researchers understand how social and reward behavior works.

References

1. Carta, et. al., Cerebellar modulation of the reward circuitry and social behavior. Science 363, (2019). doi: 10.1126/science.aav0581  
2. Image retrieved from: https://commons.wikimedia.org/wiki/File:1613_Major_Regions_of_the_Cerebellum-02.jpg