Abstract
Purpose :
Visual information is transmitted from the eye to the brain in the spiking activity of population of retinal ganglion cells (RGCs). RGCs exhibit frequently correlated firing that is a tendency for two or more cells to fire nearly simultaneously more often than expected by chance. Although correlated firing among RGCs is widespread in most mammalian species, comparisons of correlated firing pattern between species need to be explored. Therefore, here, we compared the correlated firing in mouse and monkey retina and tried to understand its functional role on visual information processing.
Methods :
Retinas from mouse; wild-type (WT, C57BL/6J strains, postnatal week 8) and rd1 (C3H/HeJ strains, PNW 10) and WT marmoset monkeys; postnatal day 1 (PND1) and postnatal years 3 (PNY3) were used. Retinal ganglion cell (RGC) spikes without applying visual or electric stimulus were recorded in isolated whole-mount retina using 8 × 8 multi-electrode array (MEA). The pattern of interaction between two RGCs was studied by the cross-correlation analysis. Correlation index according to distance of two RGCs was calculated.
Results :
In WT mouse retina, RGCs hardly showed correlated firing, while in rd1 mouse, RGC spikes showed broad correlation (synchronized firing within 100 msec). In marmoset monkey retinas, two RGC spikes showed narrow correlation (synchronized firing within 2 msec). Correlation indexes according to distance of two RGCs were decreased in all retinas irrespective of species. However, there were significant differences of correlation indexes among species. Each index at distance of 200 μm was 10.7 ± 0.03 (WT mouse), 15.1 ± 0.04 (rd1 mouse), 12.0 ± 0.04 (PND1 monkey) and 37.4 ± 0.18 (PNY3 monkey). RGCs of PNY3 monkey retina showed strong correlation compared with other groups. Although some RGCs of PND1 monkey retina showed strong correlation, most RGCs were rarely correlated.
Conclusions :
These results suggest that monkey retina has distinct visual information processing, which is very different with mouse retina. Correlated firing of neonatal monkey retina (PND1) seems to be partial compared with adult monkey retina (PNY3) maybe due to immature formation of retinal circuit. In future study, we would like to focus on information processing of primate retina, which eventually leads us to better understanding of visual information encoding of human being.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.