The inner plexiform layer is an area of the retina that is made up of a dense reticulum of fibrils formed by interlaced dendrites of retinal ganglion cells and cells of the inner nuclear layer. This is where amacrine and bipolar cells synapse at the dendrites of the ganglion cells. Within this reticulum a few branched spongioblasts are sometimes embedded. To isolate the ON and OFF signals bound for the brain, this layer has two sublaminae.
References
External links https://www.webvision.pitt.edu/book/part-ii-anatomy-and-physiology-of-the-retina/inner-plexiform-laye/