Abstract
The receptive field (RF) of single visual neurons undergoes progressive refinement during development. It remains largely unknown how the excitatory and inhibitory inputs on single developing neurons are refined in a coordinated manner to allow the formation of functionally correct circuits. Using whole-cell voltage-clamp recording from Xenopus tectal neurons, we found that RFs determined by excitatory and inhibitory inputs in more mature tectal neurons are spatially matched, with each spot stimulus evoking balanced synaptic excitation and inhibition. This emerges during development through a gradual reduction in the RF size and a transition from disparate to matched topography of excitatory and inhibitory inputs to the tectal neurons. Altering normal spiking activity of tectal neurons by either blocking or elevating GABA(A) receptor activity significantly impeded the developmental reduction and topographic matching of RFs. Thus, appropriate inhibitory activity is essential for the coordinated refinement of excitatory and inhibitory connections.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Action Potentials / drug effects
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Action Potentials / physiology
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Afferent Pathways / drug effects
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Afferent Pathways / growth & development
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Afferent Pathways / physiology*
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Animals
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Excitatory Postsynaptic Potentials / drug effects
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Excitatory Postsynaptic Potentials / physiology*
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GABA Agonists / pharmacology
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GABA Antagonists / pharmacology
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Glutamic Acid / metabolism
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Neural Inhibition / drug effects
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Neural Inhibition / physiology*
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Neuronal Plasticity / physiology
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Optic Nerve / physiology
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Patch-Clamp Techniques
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Receptors, GABA-A / drug effects
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Receptors, GABA-A / metabolism
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Retinal Ganglion Cells / physiology
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Superior Colliculi / drug effects
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Superior Colliculi / growth & development
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Superior Colliculi / physiology*
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology
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Visual Fields / drug effects
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Visual Fields / physiology*
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Xenopus laevis
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gamma-Aminobutyric Acid / metabolism
Substances
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GABA Agonists
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GABA Antagonists
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Receptors, GABA-A
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Glutamic Acid
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gamma-Aminobutyric Acid