Related Experiment Video
Updated: May 14, 2026
10:53
Optogenetic Stimulation of the Auditory Nerve
Published on: October 8, 2014
[Site of cochlear stimulation and its effect on electrically evoked compound action potentials using the Nucleus24
Ying Tian1, Wei Li, Zheng Wang
1Department of Otorhinolaryngology, the First Affiliated Hospital, China Medical University, Shenyang, 110001, China. ty31505@163.com
Summary
Neural response telemetry (NRT) software revealed that electrically evoked auditory nerve action potential (ECAP) properties vary based on cochlear region. Apical recordings showed higher amplitudes, lower thresholds, and steeper slopes, indicating significant regional differences.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Audiology
Context:
- Cochlear implants (CIs) are vital for hearing restoration.
- Understanding the neural response to CI stimulation is crucial for optimizing device performance.
- Electrically evoked compound action potentials (ECAPs) provide insights into neural activity.
Purpose:
- To investigate regional differences in ECAP properties within the cochlea using NRT software.
- To determine if ECAP amplitude, threshold, and slope are influenced by the stimulated and measured cochlear region.
Summary:
- ECAPs were recorded intraoperatively from 27 Nucleus CI24R (CA) users using NRT software.
- Electrodes spanning apical to basal regions were tested, measuring ECAP amplitude, threshold, and slope.
- Apical recordings demonstrated significantly higher ECAP amplitudes, lower thresholds, and steeper amplitude growth functions compared to other regions.
Impact:
- Findings highlight considerable variability in ECAPs based on cochlear location.
- This variability must be considered for accurate interpretation of ECAP measures.
- Results can inform programming strategies for cochlear implants to improve patient outcomes.
Related Concept Videos
01:13The Cochlea
The cochlea is a coiled structure in the inner ear that contains hair cells—the sensory receptors of the auditory system. Sound waves are transmitted to the cochlea by small bones attached to the eardrum called the ossicles, which vibrate the oval window that leads to the inner ear. This causes fluid in the chambers of the cochlea to move, vibrating the basilar membrane.
01:15Auditory Pathway
Auditory pathways constitute the complex neural circuits responsible for transmitting and interpreting auditory information from the peripheral auditory system to the brain. Sound waves are initially captured by the outer ear, funneled through the ear canal, and reach the tympanic membrane (eardrum). These vibrations are transmitted via the middle ear's ossicles to the inner ear's cochlea.
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
01:22Hair Cells
Hair cells are the sensory receptors of the auditory system—they transduce mechanical sound waves into electrical energy that the nervous system can understand. Hair cells are located in the organ of Corti within the cochlea of the inner ear, between the basilar and tectorial membranes. The actual sensory receptors are called inner hair cells. The outer hair cells serve other functions, such as sound amplification in the cochlea, and are not discussed in detail here.
01:28Action Potential: Phases of Stimulation
The action potential is a complex electrical event that occurs in excitable cells, such as neurons and muscle cells. It consists of several distinct phases, each with specific characteristics.
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...
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...
01:41Action Potentials
Overview
01:14Action Potential
Neurons communicate by firing action potentials—the electrochemical signal that is propagated along the axon. The signal results in the release of neurotransmitters at axon terminals, thereby transmitting information to the nervous system. An action potential is a specific "all-or-none" change in membrane potential that results in a rapid spike in voltage.
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...