Abstract
Purpose:
During retinal degeneration, retinal ganglion cells (RGCs) develop rhythmic bursting activity. To correlate abnormal activity with morphological classes of retinal ganglion cells affected by retinal degeneration, we compared electrophysiological recordings to structural features using cluster analysis.
Methods:
Excitatory and inhibitory postsynaptic currents were recorded from ~300 RGCs from rd1 mouse whole mount retinas. Cells were infused with sulforhodamine for visualization using a Nikon C1 confocal microscope. Anatomical and physiological parameters were used in a cluster analysis, and were also compared using a general linear model. Fourier analysis was used to determine the dominant frequency component and strength of rhythmic physiological activity. Monostratified and bistratified RGCs were analyzed separately.
Results:
All analyzed RGCs exhibited spontaneous oscillatory activity characteristic of rd mutants. This activity correlated to the level of stratification of monostratified RGCs within the inner plexiform layer. Oscillatory currents in bistratified RGCs have a stronger inhibitory component overall. Larger dendritic field size and density are associated with more robust oscillations, varying with stratification level.
Conclusions:
The correlation of aberrant activity to stratification suggests that ON and OFF pathways may be differently affected by degeneration. However, differences in dendritic fields within broad classes also contribute to variations in oscillatory activity.
Keywords: 494 degenerations/dystrophies •
508 electrophysiology: non-clinical •
531 ganglion cells