Functional and Anatomical Properties of Cck Cells in the Medial Habenula

(In-Person) Poster Presentation 

Previous research has shown that the medial habenula (MHb) is involved in many behaviors, such as stress, depression, addiction, and reward-guided behavior, but the organization of neurons driving these behaviors is unclear. MHb neurons have traditionally been divided into two groups based on expression of ChAT and Tac1 and studies have demonstrated that Tac1 cells are involved in rewardguided behavior. More recent work has suggested that the MHb contains additional cell types and Cck has been identified as a potential marker for a subset of Tac1 cells. In this project, I aim to confirm that Cck cells are a subset of Tac1 cells, as well as examine functional and anatomical differences between these two cell types. To examine RNA expression overlap between Cck and Tac1, I am conducting RNA in situ hybridization experiments. To examine Cck cell function, I am recording neural activity of Cck cells in mice during reward-guided behavior. To examine Cck anatomical projections, I am imaging fluorescently-labeled Cck axon projections. Preliminary results from experiments thus far suggest that Cck cells respond to withheld reward (similar to Tac1 cells) and appear to project through the interpeduncular nucleus, rather than stopping there like most Tac1 projections. Results from these experiments will inform future work in the MHb as researchers continue to study the cell types of the habenula, especially as potential targets for treatment of conditions like addiction or depression.