Abstract
The hippocampus and prefrontal cortex are functionally and structurally connected; oscillatory communication between these two brain structures play a crucial role in memory-guided behaviors. Optogenetics is a technique that can be used to investigate the relationship between these regions by manipulating neural activity using light. Viral vectors can be used to incorporate a particular gene into a cell to produce light-gated ion channels or pumps. These pumps can lead to gain-of-function or loss-of-function for the cell, and depending on the promoter used, can result in an overall activation or inactivation of a cell population. In the following experiments, two different serotypes were compared (AAV9 vs AAV5) for the spread of expression in either the hippocampus or the prefrontal cortex. Both a gain-of-function (channelrhodopsin) and a loss-of-function (ArchT) opsins were tested using both serotypes. These experiments qualitatively validated the greater spread of expression for the AAV9 serotype compared to the AAV5 in the hippocampus. Future studies will focus on the use of AAV9 for wide-spread targeting of cell populations.