THE MODE OF IMPULSE CONDUCTION THROUGH THE SPINAL GANGLION
1959 Volume 9 Issue 1 Pages 33-42
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1959 Volume 9 Issue 1 Pages 33-42
1. The conduction of the impulse through toad spinal ganglion was studied by analysing the action potential obtained from the ganglion cells with an intracellular electrode and by recording the conducted spike potential from the peripheral nerve or from the dorsal root.
2. By making the cell hyperpolarised and refractory the site generating the M spike, the smallest component of the intracellular spikes, was confirmed to be nodes of Ranvier locating between the non-myelinated segment and the bifurcation and including the one at the bifurcation.
3. The conduction from the dorsal root to the bifurcation was blocked by a smaller hyperpolarisation than that from the peripheral nerve, and the least interval of the former was longer than that of the latter.
4. Urethane affected the centrifugal conduction through the spinal ganglion much more than the centripetal one, indicating that the conduction from the bifurcation to the dorsal root has a larger safety factor than that of the inverse direction.
5. Repetitive activation of the nerve affected the conduction from the bifurcation to the cell body more than that through the bifurcation from the peripheral nerve to the dorsal root. This was correlated with the development of the ganglion cell from a bipolar type in fishes to a monopolar one in higher vertebrates.
