Effects of dopamine on response properties of ON-OFF RGCs in encoding stimulus durations

Abstract

Single retinal ganglion cell's (RGCs) response properties, such as spike count and response latency, are known to encode some features of visual stimuli. On the other hand, neuronal response can be modulated by dopamine (DA), an important endogenous neuromodulator in the retina. In the present study, we investigated the effects of DA on the spike count and the response latency of bullfrog ON-OFF RGCs during exposure to different stimulus durations. We found that neuronal spike count and response latency were both changed with stimulus durations, and exogenous DA (10 μM) obviously attenuated the stimulus-duration-dependent response latency change. Information analysis showed that the information about light ON duration was mainly carried by the OFF response and vice versa, and the stimulation information was carried by both spike count and response latency. However, during DA application, the information carried by the response latency was greatly decreased, which suggests that dopaminergic pathway is involved in modulating the role of response latency in encoding the information about stimulus durations.

Coding Properties of Mouse Retinal Ganglion Cells with Dual-Peak Patterns with Respect to Stimulus Intervals

“…The response latencies of the first and second peak were shortened significantly when light-OFF interval was increased (Figure 3E , paired t -test, p < 0.05), while spike counts of both peaks tended to be increased significantly (Figure 3F , paired t -test, p < 0.05). This was consistent with previous findings in bullfrog retina (Xiao et al, 2014a , b ).…”

“…This might be due to that the changes of latency and firing rate were correlated, i.e., an increased latency was normally accompanied by a decreased firing rate, and vice versa. Negative correlation between latency and firing rate was also a common observation throughout the visual system, which was reported to be related to the strength of stimuli (Maunsell et al, 1999 ; Reich et al, 2001 ; Risner et al, 2010 ; Xiao et al, 2014a , b ). Thus it is presumable that there might be some common mechanism contributing to the changes of latency and firing rate (Cleland and Enroth-Cugell, 1970 ; Lennie, 1981 ).…”

Clinical Significance and Pathogenesis of Visual Impairment in Parkinson’s Disease

“…The most prominent interaction between CS disturbance and retinal dopamine has been revealed in patients with motor fluctuations during the «on» and «off» periods. Our evidence of improved CS during the «on» period and reduced CS during the «off» period is agreement with data published by authors from other countries and demonstrates that CS can vary due to the effect of levodopa drugs [20][21][22]. However, what defines the variability of CS fluctuation in different patients is still unknown.…”

Editorial: What can simple brains teach us about how vision works

“…Finally, one research article uses the retina of an amphibian, the bullfrog, to study the effect of dopamine on the processing of visual information (Xiao et al, 2014 ). Dopamine is synthesized and released by interplexiform and amacrine cells in the bullfrog retina and is known to exert a number of important modulatory effects on retinal responses.…”