We are interested in understanding the synaptic interactions underlying visual information processing. The vertebrate retina is ideally suited for studying synaptic interactions. It is an accessible part of the central nervous system, which can be stimulated physiologically with light. The laboratory studies how synaptic signals mediated by subtypes of GABA and glutamate receptors are shaped in specific retinal circuits. A major interest is in how excitatory signals mediated by glutamate are affected by receptor properties and uptake mechanisms. Glutamate transporters and receptor desensitization may play a more significant role in signal shaping in the retina than in most other parts of the CNS, making the retina a model system for investigating these phenomena. We are also investigating how inhibitory signals mediated by GABAA and GABAC receptors affect visual information processing. GABAC receptors are remarkable in that they are abundant in the retina, but sparsely distributed in other parts of the CNS. Using pharmacological techniques and knockout mice, we found that these subtypes of GABA receptors have different functional properties and are differentially distributed on particular types of neurons, where each receptor may shape inhibitory signals in distinct ways. The roles of neurotransmitters in visual processing are studied by making whole-cell patch recordings from morphologically identified neurons in the retinal slice preparation. These studies will help define how the neurotransmitters glutamate and GABA function in specific neural circuits used to process different forms of visual information.
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- Ichinose T, Shields CR, Lukasiewicz PD. Sodium channels in transient retinal bipolar cells enhance visual responses in ganglion cells. J Neurosci. 2005 Feb 16;25(7):1856-65. PubMed PMID: 15716422.