Intracellular recordings from a biplexiform ganglion cell in macaque retina, stained with horseradish peroxidase.

A biplexiform ganglion cell, which is characterized by dendritic contacts with rods, has been penetrated with an HRP-filled microelectrode in the retina of Macaca fascicularis. Its fine curvy axon could be traced to the optic disc. One of several dendritic processes ascended through all retinal layers and ended in the layer of rod spherules. Under all conditions of chromatic adaption, the cell produced depolarizing responses with a rapid onset and a slow decay. Besides a strong rod input the recordings indicate signals from at least two spectrally different cone mechanisms.