axon synapses in cone retinal bipolar cell type 1 cone bipolar cell (sensu Mus) An OFF-bipolar neuron found in the retina and having connections with cone photoreceptors cells and neurons in the outer half of the inner plexiform layer. The cell body of these cells is in the middle of the inner plexiform layer. The dendritic tree is stout and the axon terminates in sublamina 1. The axonal terminal is wide and has only a few varicosities. DB1 cone bipolar cell sublaminar layer S1