Abstract
Purpose :
Detection and recognition of visual temporal pattern is essential for visual prediction and error detection. However, the basic mechanism of retinal responses to distinct temporal patterns is still largely unclear. Specifically, how retinal ganglion cells (RGCs) encode the visual information of temporal ramping pattern in which the feature of temporal sequence is constantly increasing or decreasing has not been systematically studied. Here we explored how the firing pattern of RGCs conveys the information of temporal ramping signal.
Methods :
Retinas from 6-8 weeks of wild type mice were used in the present study. The blue light LED was used to provide visual stimulation to the retina and the multi-electrode array (MEA) was used to record the spiking activity of RGCs. Two temporal ramping patterns were generated in this experiment, including (1) contrast polarity and (2) temporal frequency increasing or decreasing constantly in magnitude. In the contrast polarity changing scheme, the temporal sequence of flash whose duty cycle of light and dark period was constantly increasing or decreasing. In the frequency changing scheme, the inter-pulse interval of flash was constantly increasing or decreasing, resulting in temporal frequency ramping.
Results :
In both experiments, based on the temporal pattern of RGCs spiking response, we found that the retina can distinguish between the periodic and ramping stimuli, and it can also discriminate the increased ramping sequence from the decreased ramping one. Furthermore, ON and OFF RGCs showed distinctly different responses to these temporal ramping patterns. In addition, the spike timing of RGCs was found to correlate with the changing rate of temporal frequency ramping. This suggests that the retina can also distinguish different ramping slopes of the temporal sequence.
Conclusions :
The present study shows that the retina is capable of encoding the information of temporal ramping stimulus and its changing rate by distinct firing patterns of different RGC types. This finding supports that the retina can extract the regularity of temporal sequence and responds to it adaptively.
This is a 2020 ARVO Annual Meeting abstract.