Related Experiment Video
Updated: Jun 12, 2026
04:59
Spinal Cord Electrophysiology
Published on: January 18, 2010
Spinal interneuron circuits reduce approximately 10-Hz movement discontinuities by phase cancellation
Elizabeth R Williams1, Demetris S Soteropoulos, Stuart N Baker
1Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom.
Summary
This study reveals that the spinal cord (SC) plays a crucial role in tremor reduction by generating opposing brain signals. This neural mechanism helps improve movement precision in both healthy individuals and those with neurological disorders.
Area of Science:
- Neuroscience
- Motor Control
- Systems Neuroscience
Background:
- Tremor limits fine motor control in healthy individuals and is a disabling neurological symptom.
- Voluntary slow finger movements exhibit discontinuities (steps) around 10 Hz, linked to primary motor cortex (M1) activity.
- The neural network underlying tremor involves distributed brain areas beyond M1.
Purpose of the Study:
- To investigate the contribution of subcortical areas—deep cerebellar nuclei (DCN), pontomedullary reticular formation, and spinal cord (SC)—to tremor generation during slow finger movements.
- To analyze local field potential (LFP) and single-unit activity in these areas for coherence with movement.
- To understand the phase relationships of neural oscillations in these areas relative to M1.
Main Methods:
- Recordings of local field potential (LFP) and single-unit activity from the DCN, pontomedullary reticular formation, and SC in two macaque monkeys.
- Monkeys were trained to perform slow finger movements.
- Coherence analysis between neural activity and finger acceleration was performed in the tremor frequency range (6-13 Hz).
Main Results:
- Coherence between LFP and acceleration was significant (6-13 Hz) across all recorded areas (DCN, reticular formation, SC), confirming a distributed network.
- The phase of coherence in DCN and pontomedullary reticular formation matched previous M1 findings.
- The SC exhibited an antiphase relationship (differing by ~pi rad) compared to M1, confirmed by single-unit discharge analysis.
Conclusions:
- The spinal cord (SC) contributes to tremor by generating oscillations with a phase opposite to that of M1 and other subcortical areas.
- This antiphase signaling from the SC, when converging with descending inputs, can cancel 10 Hz oscillations at the motoneuronal level.
- This cancellation mechanism may reduce muscle drive at tremor frequencies, thereby improving movement precision and reducing disabling tremor.
Related Concept Videos
01:25Neural Circuits
Neural circuits and neuronal pools are two of the main structures found in the nervous system. Neural circuits are networks of neurons that work together to carry out a specific task or process. They consist of interconnected neurons and glial cells, which provide structural and metabolic support.
Neuronal pools are collections of nerve cells with similar functions and interact through chemical and electrical signals. These pools include both interneurons (the central neural circuit nodes that...
Neuronal pools are collections of nerve cells with similar functions and interact through chemical and electrical signals. These pools include both interneurons (the central neural circuit nodes that...
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...
01:10Spinal Cord: Information Processing
The spinal cord is an integral hub for motor and sensory information that enables the brain to communicate with the peripheral nervous system (PNS). This communication consists of relaying sensory data and transmission of motor commands.
Sensory Information Processing
Sensory information processing begins at the sensory receptors located in the skin and other tissues, which detect somatic sensory stimuli such as touch, temperature, or pain. These receptors function as catalysts, initiating...
Sensory Information Processing
Sensory information processing begins at the sensory receptors located in the skin and other tissues, which detect somatic sensory stimuli such as touch, temperature, or pain. These receptors function as catalysts, initiating...
01:22Muscle Stimulation Frequency
The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
01:19The Neuromuscular Junction
The nervous system consists of complex motor neuron circuits, including upper motor neurons originating from the cerebral cortex and lower motor neurons starting in the spinal cord, coordinating both voluntary and involuntary movements. Among these, somatic motor neurons activate skeletal muscles and are classified into alpha, beta, and gamma types. Alpha neurons are vital for voluntary movement coordination, while gamma neurons adjust muscle spindle sensitivity, and the function of beta...
01:27Diencephalon: Thalamus and Information Relay
The thalamus, often called “the gateway to the cerebral cortex,” is vital in processing and directing sensory and motor signals throughout the brain. Almost all inputs destined for the cerebral cortex, except for olfactory signals, are relayed through the thalamus. The thalamus is a sophisticated relay station, channeling information from various brain regions to the cerebral cortex, as well as a filter, prioritizing certain signals over others based on current physiological states or needs.