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Updated: Jun 21, 2026
08:02
Generation of Local CA1 γ Oscillations by Tetanic Stimulation
Published on: August 14, 2015
Subthreshold oscillations generated by TTX-sensitive sodium currents in dorsal cochlear nucleus pyramidal cells
Paul B Manis1, Scott C Molitor, Huijie Wu
1Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7070, USA. pmanis@med.unc.edu
Experimental Brain Research
|September 26, 2003
Summary
Subthreshold voltage oscillations in dorsal cochlear nucleus pyramidal cells are crucial for controlling action potential timing. These oscillations depend on voltage-gated sodium channels and influence neuronal firing patterns near spike threshold.
Area of Science:
- Neuroscience
- Cellular Electrophysiology
Background:
- Dorsal cochlear nucleus (DCN) pyramidal cells (PCs) display varied firing patterns based on initial membrane potential.
- These patterns include 'pauser' and 'buildup' responses with distinct silent intervals preceding action potentials.
Purpose of the Study:
- To investigate the nature and underlying mechanisms of subthreshold voltage oscillations observed in DCN PCs.
- To determine the role of these oscillations in controlling neuronal excitability and spike timing.
Main Methods:
- Whole-cell recordings from DCN PCs in rat pup brainstem slices (P10-14).
- Application of depolarizing current injections and pharmacological agents (neurotransmitter antagonists, tetrodotoxin, phenytoin, Cd2+).
Main Results:
- Subthreshold voltage oscillations (40-100 Hz) were observed during slow depolarization towards spike threshold.
- Oscillations were independent of neurotransmitter actions but significantly suppressed by tetrodotoxin, indicating a role for voltage-gated sodium channels.
- Oscillation amplitude increased as membrane potential approached spike threshold.
Conclusions:
- Voltage-gated sodium channels are essential for generating subthreshold membrane oscillations in DCN PCs.
- These oscillations likely play a critical role in regulating spike timing, particularly when the membrane potential is near the firing threshold.
Related Concept Videos
01:41Action Potentials
Overview
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.
01:13The 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.
01:19The 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.
01:23Propagation of Action Potentials
The propagation of an action potential refers to the process by which a nerve impulse, or "action potential," travels along a neuron.
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...
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...