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Stimulus-evoked modulation of sensorimotor pyramidal neuron EPSPs.
Adam Kohn1, Carol Metz, Mark A Tommerdahl
1Curriculum in Neurobiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA. adamk@cns.nyu.edu
Journal of Neurophysiology
|December 6, 2002
Summary
Repetitive stimulation of sensory cortex rapidly alters neuronal input efficacy, enhancing some inputs while weakening others. This dynamic change, possibly involving glial cells and extracellular potassium, modifies how neurons process information.
Area of Science:
- Neuroscience
- Cellular Electrophysiology
- Sensory Cortex Function
Background:
- Neuronal receptive fields change dynamically with sensory input.
- These receptive field dynamics suggest alterations in synaptic input efficacy.
- Investigating input efficacy changes in layer V pyramidal cells of the sensory cortex.
Purpose of the Study:
- To determine if brief repetitive stimulus drive alters corticocortical input efficacy to layer V pyramidal cells.
- To investigate the mechanisms underlying these input efficacy changes.
Main Methods:
- Whole-cell recordings from layer V pyramidal cells in vitro.
- Repetitive electrical stimulation at the layer VI/white matter border.
- Evoked synaptic responses via layer I or layer II/III stimulation and local glutamate application.
Main Results:
- Repetitive stimulation potentiated excitatory postsynaptic potentials (EPSPs) from layer II/III inputs by 97%.
- The same stimulation attenuated responses from layer I inputs.
- Stimulus-evoked glial depolarization and increased extracellular potassium correlated with EPSP potentiation.
Conclusions:
- Brief repetitive stimulus drive induces rapid, transient, and specific alterations in synaptic input efficacy.
- These changes involve postsynaptic mechanisms, potentially including voltage-dependent sodium channels.
- Glial cell activity and extracellular potassium dynamics may contribute to synaptic plasticity in the sensory cortex.