Oh, The Place Cells You’ll Go!

I have been thinking about my project from one direction. As I am looking at a specific gene linked with autism, I know the process of how the gene is translated into mRNA then into a protein. After that the protein possibly stabilizes a cell adhesion molecule. The big picture goal would be to understand how this gene affects behavior. Knowing that when this gene is silenced, I could map the cellular processes which lead to behavioral abnormalities. Unfortunately, this thinking has not lead very far as we do not even know what cell adhesion molecule is stabilized by the protein. One of the many positive outcomes of listening to my talented peers present their chalk talks was it made me think about my project from a different direction. 

Alissa Kong’s research project is to analyze how visual manipulations affect spatial memory. When you move, your brain is aware of what you are doing. This cognitive ability is known as path integration. You also visually take in your surroundings; your brain is able to integrate this sensory stimuli into path integration. The Gong lab is focused on the role of place cells in this process. Place cells are hippocampal neurons which have been implicated in spatial memory. Alissa’s lab is using virtual reality to test the changes in how place cells fire in response to visual stimuli. 

In the hippocampus of mice, the Gong lab first injects a virus which transmits a protein into the place cells. The protein will bind to calcium and fluoresce, which allows for the mapping of when these cells fire. A 1-photon microscope attached to the mouse records the fluorescence data. These mice are then placed on a treadmill with a virtual reality display in front of them. The mice are divided into experimental and control groups. The control group mice see a normal track which they “virtually” run across. The experimental group runs across a track that has been altered in an unnatural way. This variable is designed to test how the brain uses visual information to correct path integration. During these tests, the 1-photon microscope records the fluorescence outputs from the path cells. Alissa has hypothesized that path cells will fire when the visual manipulation occurs indicating that these cells correct physical sensory information.

Alissa’s project is trying to understand one interesting ability of the brain by taking a video of the cells in a live mice. By imaging the firing of these cells, you can then begin to understand the mechanism that allows the cells to fire. The design of Alissa’s experiment made me think about the multitude of different angles to approach my research question and the very cool technologies that make these methods possible.

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