Social Behavior Tied to Activity in Specific Brain Circuit

A team of Stanford University investigators has linked a particular brain circuit to mammals’ tendency to interact socially. Stimulating this one circuit instantly increases a mouse’s appetite for getting to know a strange mouse, while inhibiting it shuts down its drive to socialize with the stranger. The new findings, recently published in Cell, may throw light on psychiatric disorders marked by impaired social interaction, such as autism and social anxiety, said the study’s senior author, Karl Deisseroth, MD, PhD. The findings are also significant in that they highlight the specific components of brain circuits involved in a complex behavior. A combination of cutting-edge techniques permitted analysis of how brain activity controls behavior. Using a combination of optogenetics and fiber photometry, the researchers were able to both manipulate and monitor activity in specific nerve-cell clusters, and the fiber tracts connecting them, in mice’s brains in real time while the animals were exposed to either murine newcomers or inanimate objects in various laboratory environments. The mice’s behavioral responses were captured by video and compared with simultaneously recorded brain-circuit activity. The investigators were able to demonstrate that a particular tract projecting from the ventral tegmental area to the nucleus accumbens was the relevant conduit carrying the impetus to social interaction in the mice. To learn more about the study, click here.