Comparing retinal reflectance changes elicited by transcorneal electrical retinal stimulation with those of optic chiasma stimulation in cats.
Summary of "Comparing retinal reflectance changes elicited by transcorneal electrical retinal stimulation with those of optic chiasma stimulation in cats."
To compare retinal reflectance changes (RCs) elicited by transcorneal electrical stimulation (TES) to those elicited by electrical stimulation of the optic chiasma (OX).
Two eyes of two cats were studied under general anesthesia. Biphasic electrical pulses at 20 Hz were applied for 5 ms in TES, and monophasic pulses were applied for 50 μs at 100 Hz in OX stimulation. Fundus images observed with near-infrared light (800-880 nm) were recorded every 25 ms for 26 s, beginning 2 s before and ending 20 s after the electrical stimulation. To improve the signal-to-noise ratio, the images of ten consecutive recordings were averaged. Two-dimensional topographic maps of the RCs were constructed by subtracting images before the stimulation from those after the stimulation. The electrically evoked potentials (EEPs) were recorded at the OX. The effect of an intravitreal injection of tetrodotoxin (TTX) on the RCs elicited by electrical stimulation was also determined.
After electrical stimulation, RCs were observed at the optic disc, retinal arteries, and retinal veins. The two-dimensional maps of the RCs elicited by both TES and OX stimulation were similar. The latency of the RCs ranged from 2.0 to 4.0 s, and the peak occurred 6 to 9 s after the onset of the ES. The intensity of the RCs was correlated with the amplitude of EEP elicited by TES stimulation. The RCs disappeared after the TTX injection in both TES and OX stimulation.
TES activates principally the retinal ganglion cells, and a change in the blood flow is initiated thereafter.
Topcon Research Institute, Itabashi, Japan.
This article was published in the following journal.
Name: Japanese journal of ophthalmology
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21331693
- DOI: http://dx.doi.org/10.1007/s10384-010-0906-x
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Medical and Biotech [MESH] Definitions
A group of rare, idiopathic, congenital retinal vascular anomalies affecting the retinal capillaries. It is characterized by dilation and tortuosity of retinal vessels and formation of multiple aneurysms, with different degrees of leakage and exudates emanating from the blood vessels.
Congenital, often bilateral, retinal abnormality characterized by the arrangement of outer nuclear retinal cells in a palisading or radiating pattern surrounding a central ocular space. This disorder is sometimes hereditary.
A metalloflavoprotein enzyme involved the metabolism of VITAMIN A, this enzyme catalyzes the oxidation of RETINAL to RETINOIC ACID, using both NAD+ and FAD coenzymes. It also acts on both the 11-trans- and 13-cis-forms of RETINAL.
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