The effect of motion aftereffect on optomotor response in larva and adult zebrafish

Motion aftereffect (MAE) occurs after presenting a moving stimulus to fixed subjects, as an apparent MAE the subject moves in the opposite direction. This natural process provides an excellent tool to investigate visual motion perception. Zebrafish is an important animal model with an extensive molecular toolkit, but there is a lack of the comparative understanding of its perceptual processes. This study was designed to study the optomotor response (OMR), in which the fish swims in the same direction of a moving stimulus in both adult and larvae zebrafish. Simple square wave gratings moving in a specific horizontal direction (with a precise visual angle) were shown to a test group. After an adaptation phase, a static grating was shown for a short period during which the movement of the fish was recorded. In the control group, the same procedure was applied but the grating pattern was shown moving randomly back and forth followed by a static grating. Time spent swimming in either the same or the opposite direction of the adaptation grating was recorded as line index (LI) and non-line index (NI). The results indicate that NI was more than LI for the test group, while there was no significant difference between NI and LI in the control group. These results suggest that MAE occurs in zebrafish causing OMR.