Opto-Avoidance-EPM Test

The Opto-Avoidance-Elevated Plus Maze test assesses the effect induced by photostimulation compared to a mouse's natural aversion to open areas. The elevated plus maze has the shape of a plus sign with four 35 cm arms. Two arms are open, and the other two arms are closed with 15cm high walls. The four arms intersect in the center to create a central platform. Mice naturally prefer the sheltered arms compared to the open arms. In the test, the presence of the animal in the closed arms is coupled with photostimulation (ON), while presence in the open arms/center area is coupled with NO photostimulation (OFF). If photostimulation is sufficiently aversive, it is expected to increase time in the open arms/center area.