Journal of Neurophysiology, Vol 60, Issue 5 1568-1583, Copyright © 1988 by APS
Dissection of the neuron network in the catfish inner retina. II. Interactions between ganglion cells
H. M. Sakai and K. Naka
National Institute for Basic Biology, Okazaki, Japan.
1. To characterize signal interactions between ganglion cells, extrinsic
current, either sinusoidally or white-noise modulated, was injected into a
ganglion cell and the resulting extracellular spike discharges were
recorded from a neighboring ganglion cell. 2. Current injected into an
ON-ganglion (GA) cell modulated the spike discharges of a neighboring
ON-ganglion cell (GA). Similarly, a current injected into an OFF-ganglion
(GB) cell modulated the spike discharges of a neighboring OFF-ganglion (GB)
cell. The signal transmission between ganglion cells of the same response
polarity was fast and sign-noninverting. The transfer function was lowpass
with a cutoff frequency of 30 Hz. The efficacy of the transmission was
comparable to that from bipolar or amacrine to ganglion cells of the same
polarity. 3. Current injected into an ON-ganglion (GA) cell modulated the
spike discharges of a neighboring OFF-ganglion (GB) cell; the signal
transmission was slow and sign-noninverting. Correspondingly, current
injected into an OFF-ganglion (GB) cell modulated the spike discharges of a
neighboring ON-ganglion (GA) cell; transmission was slow and
sign-inverting. 4. A brief electrical stimulation of the optic nerve
activated a single antidromic ganglion cell spike at threshold. With
suprathreshold stimulation, multiple spikes appeared, which probably were
activated orthodromically. Changes in membrane potential of ganglion and
amacrine cells induced by optic nerve stimulation usually lasted 50-80 ms,
with an initial depolarization followed by hyperpolarization. We interpret
such long-lasting responses to be mediated by reciprocal circuits that
include amacrine, bipolar, and ganglion cells. 5. Together with the
observations made by Sakai and Naka, we conclude that virtually almost all
amacrine, bipolar, and ganglion cells are functionally interconnected;
direct and fast connections are established among ON-cells and similarly
among OFF-cells, and complex, indirect connections are established between
ON- and OFF-cells.
