BIOELECTRIC SENSITIVITY TO IRRADIATION OF THE RETINA AND VISUAL PATHWAYS. UCRL-11005.

Abstract

A study was made of the acute effects of ionizing radiation on the visual pathways of the cat, as revealed by electrophysiological techniques. Irradiation sources were: 910-Mev alpha particles from a 184-in. cyclotron, 40- Mev alpha particles from a heavy ion linear accelerator, and 250-kv x rays. Rotational procedures restricted irradiation to the eye, optic tract, or optic chiasma. The b-wave amplitude of the electroretinogram served as an index of the functional sensitivity of retinal cells to unilateral irradiation. Photically evolved responses from chronically implanted bipolar electrodes in the optic tract provided a quantitative means of evaluating the influence of unilateral optictract irradiation. Midline irradiation of the optic chiasma was performed, and blockage of interocular transfer was used as a measure of the effectiveness of irradiation. Ophthalmoscopic examinations were performed on irradiated cats. Tests using 40-Mev and 910-Mev alpha particles, were carried out, to determine whether ionizing radiation affects the functional state of excitable Systems in a manner analogous to electrical stimulation. Efforts were made to evoke with ionizing-radiation action potentials from frog sciatic nerve and internodal Nitella cells. Attempts were made to induce pupillodilation in the nucleus perifornicalis of the hypothalamus of cats, by means of focused ionizing radiation.more » (auth)« less