Abstract
Cells in the superficial layers of primary visual cortex (area 17) are distinguished by feedforward input from thalamic-recipient layers and by massive recurrent excitatory connections between neighboring cells. The connections use glutamate as transmitter, and the postsynaptic cells contain both NMDA and AMPA receptors. The possible role of these receptor types in generating emergent responses of neurons in the superficial cortical layers is unknown. Here, we show that NMDA and AMPA receptors are both involved in the generation of direction-selective responses in layer 2/3 cells of area 17 in cats. NMDA receptors contribute prominently to responses in the preferred direction, and their contribution to responses in the nonpreferred direction is reduced significantly by GABAergic inhibition. AMPA receptors decrease spatial phase-selective simple cell responses and generate phase-invariant complex cell responses.
Publication types
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Research Support, Non-U.S. Gov't
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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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Animals
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Cats
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Electrodes, Implanted
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Excitatory Amino Acid Antagonists / administration & dosage
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Female
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GABA Antagonists / administration & dosage
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Iontophoresis
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Motion Perception / physiology
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Nerve Net / cytology
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Nerve Net / drug effects
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Nerve Net / metabolism
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Neural Inhibition / drug effects
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Neural Inhibition / physiology
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Neurons / drug effects
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Neurons / metabolism*
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Photic Stimulation
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Receptors, AMPA / antagonists & inhibitors
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Receptors, AMPA / metabolism*
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Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
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Receptors, N-Methyl-D-Aspartate / metabolism*
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Visual Cortex / cytology
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Visual Cortex / drug effects
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Visual Cortex / metabolism*
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gamma-Aminobutyric Acid / metabolism
Substances
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Excitatory Amino Acid Antagonists
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GABA Antagonists
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Receptors, AMPA
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Receptors, N-Methyl-D-Aspartate
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gamma-Aminobutyric Acid