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Proceedings Paper

Dynamics of VEPs in the guinea pig visual cortex under laser-light irradiation of the retina
Author(s): Galina G. Bondar
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Paper Abstract

Influence of laser irradiation (wavelength 632.8 nM) of the retina on visual evoked potentials (VEPs) in response to flashes of diffuse light have been studied. VEPs were recorded by tungsten-in-glass semimicroelectrode blocks at 700 (mu) M below cortical surface. It was revealed that VEPs were modified at all used doses of laser irradiation (power at cornea from 0.5 to 17 mW, exposure from 0.1 to 1000 s). During the initial 5 - 70 s of laser irradiation VEPs completely disappeared. After this silent period there appeared VEPs splitting into 2 - 4 distinct components and strong suppression or disappearance of VEPs first negative wave was observed. When laser irradiation was switched off VEPs negative waves were restored while the amplitude of splitting components was diminished. Restoration (frequently incomplete) of VEPs passed through a phase of increased negative wave amplitude. After the dose of laser irradiation was increased, this phase was followed by periodic changes in the amplitude of all VEPs components. Besides, the cortical zone that displayed the disturbances of the VEPs, became more extended. Long-lasting disturbances of VEPs occurred at irradiation doses close to those described in literature for ophthalmologically detected injuries. It is supposed that reversible (functional) disturbances may be identified by means of the above-mentioned phenomena. The discovered phenomena suit well the scheme which supposes disbalance and disinhibition of lateral connections between the irradiated retinal loci and the surrounding site.

Paper Details

Date Published: 22 May 1995
PDF: 8 pages
Proc. SPIE 2393, Ophthalmic Technologies V, (22 May 1995); doi: 10.1117/12.209842
Show Author Affiliations
Galina G. Bondar, Rostov State Univ. (Russia)

Published in SPIE Proceedings Vol. 2393:
Ophthalmic Technologies V
Jean-Marie Parel; Qiushi Ren; Karen Margaret Joos, Editor(s)

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