Lower limb immobilization is associated with increased corticospinal excitability

Area of Science:

• Neuroscience
• Motor System Adaptations
• Brain Plasticity

Background:

• Temporary leg immobilization, such as casting, provides a model for studying brain adaptations to reduced mobility.
• Understanding these adaptations is crucial for rehabilitation after injury, surgery, or prolonged bed rest.
• Transcranial magnetic stimulation (TMS) is a non-invasive tool to assess changes in brain excitability.

Purpose of the Study:

• To investigate if leg casting induces measurable changes in motor cortex excitability using TMS.
• To determine the time course of these excitability changes following cast removal.

Main Methods:

• Eight adult participants wore a full leg cast for 10 days.
• Motor cortex excitability was assessed using TMS at baseline, immediately after cast removal, and 24 and 48 hours post-removal.
• A control group underwent identical TMS assessments without casting.

Main Results:

• The casted group exhibited significant changes in motor cortex excitability.
• These excitability changes peaked at 24 hours after cast removal.
• The non-casted control group did not show comparable changes in excitability.

Conclusions:

• Leg casting leads to temporary, measurable alterations in brain excitability.
• These neurophysiological changes demonstrate the brain's adaptive response to immobilization.
• The findings highlight the potential of TMS in monitoring recovery from immobilization-induced neurological changes.