Abstract
Purpose: :
Previous studies showed that retinal ganglion cells (RGCs) are responsive to light stimuli at around eye opening (postnatal day P10-11) in the rabbit, and some trigger features of RGCs (e.g., direction selectivity) are also present at this developmental stage. However, active dendritic remodeling of RGCs and fine tuning of their receptive fields persist after eye opening. Thus, it is important to investigate the physiological and morphological properties of RGCs throughout development, and correlate their functional maturation with the dendritic refinement.
Methods: :
Ganglion cells from isolated retina of New Zealnad White rabbits were studied at three different developmental stages. The spatiotemporal receptive field properties of RGCs were characterized using the white noise stimuli, and the corresponding spike triggered average (STA) response was derived by reverse correlation. After extracellular recording, cells were injected with Neurobiotin to identify the cell types, and to correlate their morphological pattern with the spatial STA results.
Results: :
We found that the temporal features in STA of RGCs were immature at around eye opening. RGCs had longer stimulus integration time at P10-14 than in adult, and the correlation strength between RGCs’ response and the white noise stimuli was also significantly lower at P10-14. After P20-23, the STA pattern was adult-like. In addition, among different types of RGCs, developmental changes of STA characters in ON and OFF cells were similar, but the difference was greater in direction selective cells. Furthermore, the results of spatial STA showed less correlation with their dendritic fields at P10-14 compared to the adult RGCs.
Conclusions: :
Our results indicate that physiological and morphological properties of RGCs are still developing after eye-opening, and ribbon-synaptogenesis responsible for temporal aspects of RGCs’ receptive fields may be susceptible to visual experience.
Keywords: development • ganglion cells • receptive fields