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Real-time Electrophysiology: Using Closed-loop Protocols to Probe Neuronal Dynamics and Beyond
Published on: June 24, 2015
Cholinergic neuromodulation changes phase response curve shape and type in cortical pyramidal neurons
Klaus M Stiefel1, Boris S Gutkin, Terrence J Sejnowski
1Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California, United States of America.
Plos One
|December 17, 2008
Summary
Cholinergic neuromodulation switches cortical neuron firing dynamics by altering phase response curves (PRCs) from type II to type I. This reveals a fundamental change in how neurons generate action potentials.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Cellular Electrophysiology
Background:
- Spike generation in cortical neurons relies on intrinsic conductances.
- Phase response curves (PRCs) characterize neuronal firing responses to perturbations.
- PRC types (I and II) correlate with distinct firing mechanisms (saddle-node vs. Hopf bifurcations).
Purpose of the Study:
- To investigate the effect of cholinergic modulation on neuronal phase response curves.
- To determine if cholinergic action can alter the fundamental mechanism of spike generation.
Main Methods:
- In vitro electrophysiological recordings from layer 2/3 pyramidal neurons.
- Analysis of phase response curves (PRCs) under control and cholinergic stimulation.
- Investigating the role of potassium currents, specifically the M-current.
Main Results:
- Cholinergic action shifted the PRC from type II to type I in cortical neurons.
- This switch was associated with the down-regulation of slow voltage-dependent potassium currents, like the M-current.
- This represents the first demonstration of cholinergic neuromodulation qualitatively altering PRC type.
Conclusions:
- Cholinergic neuromodulation can fundamentally change the dynamical mechanism of spike generation in cortical neurons.
- The observed switch from type II to type I PRC suggests a transition from Hopf to saddle-node bifurcation dynamics.
- These findings highlight the plasticity of neuronal firing mechanisms under neuromodulatory control.
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