Related Experiment Video
Updated: May 23, 2026
Event-related Potentials During Target-response Tasks to Study Cognitive Processes of Upper Limb Use in Children with Unilateral Cerebral Palsy
Published on: January 11, 2016
Motor evoked potentials of the upper extremities in healthy children
Soon-Won Yook1, Sung-Hee Park, Myoung-Hwan Ko
1Department of Physical Medicine and Rehabilitation, Institute for Medical Sciences, Chonbuk National University Medical School, Research Institute of Clinical Medicine, Chonbuk National University Hospital, Jeonju 561-180, Korea.
Insights
Motor pathways to upper extremity muscles mature differently in children. Proximal muscles show slower development than distal muscles, with adult function achieved by age 13.
Area of Science:
- Neuroscience
- Developmental Biology
- Motor Control
Background:
- Understanding the maturation of the central nervous system is crucial for pediatric neurology.
- The organization of descending motor pathways influences motor skills and development.
Purpose of the Study:
- To evaluate and compare the organization of descending motor pathways to upper extremity muscles in healthy children.
- To investigate age-related changes in motor evoked potentials (MEPs).
Main Methods:
- Transcranial magnetic stimulation (TMS) applied to motor cortices.
- Motor evoked potentials (MEPs) recorded from FDI, biceps, and deltoid muscles.
- Analysis of MEP onset latency, central motor conduction time (CMCT), and amplitude.
Main Results:
- MEP acquisition improved with age for both proximal and distal muscles.
- MEP amplitudes increased with age; latencies remained relatively constant.
- Central motor conduction times (CMCTs) matured by age 13, indicating adult-like pathway organization.
Conclusions:
- Proximal and distal upper extremity muscles exhibit distinct maturation patterns.
- Motor pathway organization differs between proximal and distal muscle groups during childhood development.
Objective:
To evaluate and compare the organization of descending motor pathways to upper extremity muscles among healthy children.
Method:
The healthy children were 16 males and 7 females aged 1-19 years (average, 9 years), and eight healthy adults were enrolled as the control group. Transcranial magnetic stimulation was applied to bilateral motor cortices, and motor evoked potentials (MEPs) were recorded using surface electrodes from the first dorsal interossei (FDI), the biceps brachii (BIC), and the deltoid (DEL) muscles. The onset latency, central motor conduction time (CMCT), and amplitude were obtained during a relaxed state.
Results:
MEPs of FDI were obtained from subjects aged 13 months. The frequency of obtaining MEPs in proximal and distal muscles increased with age, although there was a less frequent incidence of obtaining MEPs in the proximal BIC and DEL muscles compared with those in the distal FDI muscle. MEP amplitudes increased with age, whereas latencies were relatively constant. CMCTs showed a similar pattern of maturation, and adult values were obtained by 13-years-of-age.
Conclusion:
These results suggest that the proximal and distal muscles of the upper extremities show different maturation and organization patterns.
