Motion Detection Pathway Search: Colocalization Study of ON Bipolar Cell Subtypes and Starburst Amacrine Cells’ Connections in the Mouse Retina

Abstract

The retina is the principal structure in vision by sensing light, which allows us to perceive motion, texture, color, and design. The electrical signals formed by the stimulus – light – must travel through multiple transparent layers. This study specifically looked at the inner plexiform layer, which consists of bipolar cells’ (BC) axon terminals and starburst amacrine cells’ (SBAC) dendrites. BC – transmit information from photoreceptors to SBAC and direction-selective ganglion cells (DSGC) in the retina – are classified as ON or OFF depending on where the axon terminals stratify at the choline acetyltransferase bands (ChAT) – band of SBAC dendrites – and their response to neuroactive molecules. The objectives of this study were to determine via immunohistochemistry whether XBC, Type 6, and Type 7 bipolar cells (BC) in mice had processes occurring at the 2nd ChAT band and how much of the total output of the three BCs occurred at the ChAT band. Processes that occur at the 2nd ChAT band would suggest that the BCs may contribute to perceiving motion since the SBAC transmit information to DSGC, which ultimately send signals to register direction of motion in cortical visual regions.