Related Experiment Video
Updated: Jul 6, 2026
06:29
Electrophysiological Measurement of Noxious-evoked Brain Activity in Neonates Using a Flat-tip Probe Coupled to Electroencephalography
Published on: November 29, 2017
Pre-stimulus alpha power affects vertex N2-P2 potentials evoked by noxious stimuli
Claudio Babiloni1, Claudio Del Percio, Alfredo Brancucci
1Dipartimento di Fisiologia Umana e Farmacologia, Università La Sapienza, Piazzale Aldo Moro 5, Rome, Italy.
Brain Research Bulletin
|March 22, 2008
Summary
Pre-stimulus alpha brain waves influence pain perception. Lower alpha-3 power before a stimulus amplifies laser-evoked potentials, suggesting a link between brain rhythms and pain processing variability.
Area of Science:
- Neuroscience
- Pain Perception
- Electrophysiology
Background:
- Pre-stimulus alpha rhythms modulate responses to non-painful stimuli.
- The influence of alpha rhythms on pain processing, specifically laser-evoked potentials (LEPs), remains less understood.
- Understanding this relationship has clinical implications for pain assessment.
Purpose of the Study:
- To investigate whether pre-stimulus alpha rhythms affect the amplitude of vertex N2-P2 potentials evoked by noxious laser stimuli.
- To explore the relationship between pre-stimulus alpha power and the variability of laser-evoked potentials.
Main Methods:
- Electroencephalography (EEG) was recorded from 30 electrodes in 10 subjects during noxious laser stimulation.
- Surface Laplacian transformation was used to enhance the vertex N2-P2 complex.
- Pre-stimulus alpha power was analyzed in three sub-bands (alpha 1, 2, and 3) based on individual alpha frequency peaks. Trials were divided into high and low pre-stimulus alpha power groups.
Main Results:
- No significant effect of pre-stimulus alpha power was observed for the alpha 1 and alpha 2 sub-bands.
- Significantly higher amplitude of vertex N2-P2 potentials was found in the weak-alpha 3 sub-group (low pre-stimulus alpha power) compared to the strong-alpha 3 sub-group (high pre-stimulus alpha power) (p<0.05).
- This suggests a specific role for the alpha 3 sub-band in modulating pain-related evoked potentials.
Conclusions:
- Pre-stimulus alpha 3 rhythms are intrinsically related to the generation of laser-evoked potentials, extending this principle to later pain processing phases.
- Fluctuations in pre-stimulus alpha rhythms, particularly in the alpha 3 band, may act as neural 'noise' influencing trial-by-trial variability in laser-evoked potentials and pain perception.
- These findings contribute to understanding the neural mechanisms underlying pain variability and have potential clinical relevance.
Related Concept Videos
01:24Local Anesthetics: Differential Sensitivity of Nerve Fibers
Local anesthetics (LAs) block the sodium channels of nerve trunks, sensory nerve endings, and neuromuscular junctions. Although LAs can block all kinds of nerves, the sensitivity of nerve fibers differs according to nerve types and structures. LAs are known to block myelinated fibers faster than unmyelinated ones. Also, they block pain or sensory neurons at low concentrations without affecting the motor neurons involved in muscle contractions. This helps relieve labor pain without affecting the...
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...
01:44Nociception
Nociception—the ability to feel pain—is essential for an organism’s survival and overall well-being. Noxious stimuli such as piercing pain from a sharp object, heat from an open flame, or contact with corrosive chemicals are first detected by sensory receptors, called nociceptors, located on nerve endings. Nociceptors express ion channels that convert noxious stimuli into electrical signals. When these signals reach the brain via sensory neurons, they are perceived as pain. Thus, pain helps the...
01:32Postsynaptic Potential (PSP)
Postsynaptic potential (PSP) refers to a change in the electrical potential of a neuron when neurotransmitters released by presynaptic neurons bind to postsynaptic receptors. This potential can either be excitatory, leading to depolarization and ultimately action potential generation, or inhibitory, leading to hyperpolarization and suppression of the postsynaptic neuron.
There are two types of receptors: ionotropic and metabotropic.
The ionotropic receptor is the membrane protein that has an...
There are two types of receptors: ionotropic and metabotropic.
The ionotropic receptor is the membrane protein that has an...