Related Experiment Video
Updated: Jul 13, 2026

In Vivo Electrophysiological Measurement of the Rat Ulnar Nerve with Axonal Excitability Testing
Published on: February 6, 2018
Inflections in threshold electrotonus to depolarizing currents in sensory axons
David Burke1, James Howells, Louise Trevillion
1Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, University of Sydney, Sydney, NSW 2006, Australia. d.burke@med.usyd.edu.au
A notch in threshold electrotonus, a technique measuring axonal excitability, is common in human sensory nerves. This finding in threshold electrotonus may affect quantitative analysis of nerve function.
Area of Science:
- Neuroscience
- Electrophysiology
Background:
- Threshold electrotonus assesses axonal excitability using subthreshold currents.
- It provides in vivo insight into internodal conductance function in humans.
- A transient reversal (notch) in threshold change is observed during depolarizing currents.
Purpose of the Study:
- To investigate the occurrence and characteristics of the notch in threshold electrotonus in human sensory axons.
- To determine if the notch observed in motor axons also appears in sensory recordings.
Main Methods:
- Standard threshold electrotonus protocol applied to human subjects.
- Recordings from sensory axons.
- Analysis of the presence and magnitude of the notch phenomenon.
Main Results:
- A notch was frequently observed in sensory recordings (33/50 healthy subjects).
- The notch can be prominent and potentially distort subsequent electrotonus phases.
- This suggests low-threshold axon activation contributes to the notch in sensory nerves.
Conclusions:
- The notch in threshold electrotonus is a common feature in human sensory axons.
- Its presence may complicate quantitative measurements and modeling of axonal function.
- Further research is needed to understand its full implications for nerve excitability studies.
More Related Videos
11:45Postsynaptic Recordings at Afferent Dendrites Contacting Cochlear Inner Hair Cells: Monitoring Multivesicular Release at a Ribbon Synapse
Published on: February 10, 2011
10:28Open-Source Real-Time Closed-Loop Electrical Threshold Tracking for Translational Pain Research
Published on: April 21, 2023
Related Concept Videos
Action Potential: Phases of Stimulation
Resting Phase:
In this phase, the cell's membrane is at its resting potential, typically around -70 millivolts (mV) for neurons. Inside the cell, there is a higher concentration of potassium ions (K+) and a lower concentration of sodium ions (Na+). Voltage-gated sodium channels are closed, and...
Action Potentials
Electrochemical Gradient and Channel Proteins: An Overview
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...
Action Potential
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
Action Potential
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
The Role of Ion Channels in Neuronal Computation
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.