Related Experiment Video
Updated: Aug 13, 2026
09:10
Determining the Functional Status of the Corticospinal Tract Within One Week of Stroke
Published on: February 22, 2020
Motor system activation after subcortical stroke depends on corticospinal system integrity
Nick S Ward1, Jennifer M Newton, Orlando B C Swayne
1Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, London, UK. n.ward@fil.ion.ucl.ac.uk
Brain : a Journal of Neurology
|January 20, 2006
Summary
After subcortical stroke, brain activation shifts to secondary motor networks when the corticospinal system (CSS) is impaired. This reorganization is partially successful in improving motor function, indicating potential therapeutic targets.
Area of Science:
- Neuroscience
- Neurology
- Rehabilitation Medicine
Background:
- Subcortical stroke often leads to motor impairments.
- Brain imaging reveals altered motor activation patterns post-stroke, with overactivation in cortical areas.
- The relationship between corticospinal system (CSS) integrity and motor network recruitment remains unclear.
Purpose of the Study:
- To investigate the hypothesis that motor region recruitment shifts from primary to secondary networks with decreasing CSS functional integrity after subcortical stroke.
- To explore the neural mechanisms underlying motor recovery and impairment in stroke survivors.
Main Methods:
- Functional MRI (fMRI) was used to measure brain activation during a motor task in eight chronic subcortical stroke patients.
- Transcranial magnetic stimulation (TMS) assessed CSS functional integrity via stimulus/response curves for the first dorsal interosseus muscle.
- Correlation analysis examined the relationship between CSS integrity (gradient of stimulus/response curve) and task-related brain activation.
Main Results:
- A negative correlation was observed between CSS functional integrity and brain activation magnitude in key motor regions, including primary motor cortex (M1), premotor cortex, supplementary motor area, intraparietal sulcus, dorsolateral prefrontal cortex, and cingulate cortex.
- Impaired CSS integrity was associated with increased activation in secondary motor networks across both hemispheres.
- No significant positive correlations were found, suggesting a shift rather than a general increase in activation.
Conclusions:
- Impaired CSS functional integrity after subcortical stroke is linked to the recruitment of secondary motor networks in both hemispheres.
- This neural reorganization aims to compensate for motor deficits but is only partially effective in reducing motor impairment.
- Findings suggest that secondary motor regions play a crucial role in attempting to restore motor output, highlighting potential targets for neurorehabilitation strategies.
Related Concept Videos
01:11Direct Motor Pathways
The direct motor pathways, also known as the pyramidal tracts, are a group of neural pathways that originate in the brain and descend through the spinal cord. They control the voluntary movement of the body. There are two major direct motor pathways: the corticospinal and the corticobulbar tracts.
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and the...
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and the...
01:22Indirect Motor Pathways
The indirect motor or extrapyramidal pathways originate in the brainstem, the lower portion of the brain that connects it to the spinal cord. They consist of several distinct tracts, each with specialized functions. The four main tracts of the indirect motor pathways are the vestibulospinal tract, the reticulospinal tract, the tectospinal tract, and the rubrospinal tract.
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01:14Motor and Sensory Areas of the Cortex
The cerebral cortex, the brain's outermost layer, is pivotal in processing complex cognitive tasks, emotions, and various sensory inputs and executing voluntary motor activities. This intricate structure is divided into three primary functional areas: the motor areas, sensory areas, and association areas.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
01:18Hierarchy of Motor Control
The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
01:13Motor Units
The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
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