Related Experiment Video
Updated: Jul 8, 2026
08:44
Dynamic Clamp Methods to Investigate Impaired Neuronal Excitability Associated with Autism
Published on: October 17, 2025
Space-clamp problems when voltage clamping neurons expressing voltage-gated conductances
Dan Bar-Yehuda1, Alon Korngreen
1Mina and Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
Journal of Neurophysiology
|January 11, 2008
Summary
Voltage-clamp studies on neurons are often distorted. Numerical simulations and experiments show that voltage-gated potassium (K+) and calcium (Ca2+) currents are significantly impacted in nonspherical cells.
Area of Science:
- Neuroscience
- Electrophysiology
- Computational Biology
Background:
- The voltage-clamp technique is crucial for studying ion channels.
- Its application to nonspherical cells like neurons is debated due to space-clamp limitations.
- Existing justifications rely on assumptions of minimal potential decay in dendritic structures.
Purpose of the Study:
- To investigate the validity of the voltage-clamp technique in nonspherical neuronal structures.
- To quantify distortions in voltage-gated currents in neurons.
- To assess the applicability of passive cable theory in justifying voltage-clamp experiments on neurons.
Main Methods:
- Numerical simulations of voltage-gated K+ and Ca2+ currents in neuronal models.
- Analysis of current distortions under varying dendritic lengths.
- Experimental validation using somatic and dendritic voltage-clamp recordings in rat neurons.
Main Results:
- Substantial distortions in voltage-gated K+ and Ca2+ currents were observed even in neurons with short dendrites.
- Passive cable theory is insufficient to justify voltage-clamp application due to shunting effects.
- Experimental data confirmed the simulation predictions of significant current distortions.
Conclusions:
- The voltage-clamp technique yields severely distorted measurements of voltage-gated currents in branching neurons.
- Assumptions underlying the use of voltage-clamp in neurons are often violated.
- Results challenge the widespread application of voltage-clamp in electrophysiological studies of neurons.
Related Concept Videos
01:18Patch Clamp
Many fundamental cell functions such as muscle contraction and nerve transmission rely on the electrical signals produced by the movement of positively and negatively charged ions across the cell membrane. One competent method to record current flowing across the whole cell or single ion channel is the patch-clamp technique.
In this method, a glass micropipette containing electrolyte solution is tightly sealed against a small portion of the cell membrane. As a result, a patch of the cell...
In this method, a glass micropipette containing electrolyte solution is tightly sealed against a small portion of the cell membrane. As a result, a patch of the cell...
01:26Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.