![]() In the retina, rod and cone photoreceptors transduce light inputs into electrochemical signals. In both systems, sensory signals stimulate sensory receptor neurons, which facilitate information transfer through specific networks formed by interneurons and then project to the cerebral cortex by output neurons. Interestingly, the retina and the olfactory bulb utilize similar neural network architecture despite processing different signals. Consequently, we determined that dopamine plays a role in visual signal processing, which is similar to its role in signal decorrelation in the olfactory bulb.Ĭontinuous integration of our sensory perceptions gives rise to our daily experience of the world, and this experience is made possible by specialized neuronal “antennae,” such as the retina and the olfactory bulb. Taken together, we found that dopamine modulates the temporal tuning of a subset of retinal bipolar cells. SKF modulated HCN and LVA currents, suggesting that these channels are the target of D 1R signaling to modulate visual signaling in these bipolar cells. To examine the mechanism of dopaminergic modulation, we recorded voltage-gated currents, hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, and low-voltage activated (LVA) Ca 2+ channels. In contrast, a D 1R antagonist, SCH-23390, reversed the effects of SKF on these types of bipolar cells. Application of a D 1R agonist, SKF-38393, shifted the peak temporal responses toward higher frequencies in a subset of bipolar cells. We recorded excitatory postsynaptic potentials (EPSPs) evoked by various frequencies of sinusoidal light in the absence and presence of a dopamine receptor 1 (D 1R) agonist or antagonist. To elucidate dopaminergic effects on visual processing, we conducted patch-clamp recording from second-order retinal bipolar cells, which exhibit multiple types that can convey different temporal features of light. While dopamine is essential for signal discrimination in the olfactory system, it is not understood whether dopamine has similar roles in visual signal processing in the retina. In the olfactory system, dopamine mediates lateral inhibition between the glomeruli, resulting in odorant signal decorrelation and discrimination. ![]() In the retina, dopamine adjusts the retinal network for daylight conditions (“light adaptation”). Interestingly, dopamine modulates sensory signal transduction in both systems. These networks filter sensory signals based on their unique features and adjust their sensitivities by gain control systems. Sensory receptors receive signals that are transmitted to neural networks before projecting to primary cortices. ![]() The retina and the olfactory bulb are the gateways to the visual and olfactory systems, respectively, similarly using neural networks to initiate sensory signal processing.
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