Purchase this article with an account.
Y. Kurimoto, M. Kondo, S. Ueno, T. Sakai, S. Machida, H. Terasaki; Asymmetry of Focal Macular Photopic Negative Responses (phnrs) in Monkeys. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2171.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The photopic negative response (PhNR) is a slow, negative-going wave of the photopic electroretinogram (ERG) that appears after the b-wave. The aim of this study was to determine whether there is any asymmetry in the amplitude of the PhNR elicited from the upper and lower macular areas, and between the nasal and temporal macular areas in rhesus monkeys.
Focal macular ERGs were recorded from five rhesus monkeys using a modified infrared fundus camera, in which a red stimulus spot on a blue background illumination were incorporated (Kondo, Kurimoto, et al. 2008). In this study, red hemi-circular stimuli were presented on a blue background. Focal macular PhNRs were also recorded before and after intravitreal injection of tetrodotoxin (TTX).
The PhNR from the upper macular area was significantly larger than that of the lower macular area, and the PhNR of the nasal macula was significantly larger than that of the temporal macula. These asymmetries were present in the focal PhNR elicited by both brief and long duration stimuli, and the asymmetries were completely eliminated by an intravitreal injection of tetrodotoxin (TTX).
These results suggest that the upper-lower and nasal-temporal asymmetries of PhNR in the primate retina are mainly caused by TTX-sensitive spiking activities of inner retinal neurons.
This PDF is available to Subscribers Only