Proximal Negative Response of the Inner Plexiform Layer

Abstract

Our knowledge of the inner plexiform layer has been greatly extended by recent electron microscopic studies (Dowling, 1968), which show that amacrine cells play an important role in its synaptic organisation. In the inner plexiform layer interactions between bipolar cells, amacrine cells and ganglion cells shape the final output from the retina to the brain. The electron microscopic studies suggest the generalisation that in those retinae where ganglion cells can be shown physiologically to have complex properties, such as movement sensitivity, amacrine cells act an interneurons between bipolar cells and ganglion cells. In this note an account is given of a newly identified component of the local electroretinogram which can be recorded extracellularly in the inner plexiform layer: this component is the proximal negative response (PNR).