Motor imagery of foot dorsiflexion and gait: effects on corticospinal excitability.
OBJECTIVE
We examined how corticospinal excitability was affected by motor imagery of foot dorsiflexion and motor imagery of gait.


METHODS
Transcranial magnetic stimulation was applied over the primary motor cortex of 16 young healthy subjects while they performed imaginary foot dorsiflexions (Experiment I) and imaginary walking (Experiment II). Motor-evoked potentials (MEPs) were recorded from the tibialis anterior (TA) and first dorsal interosseus (FDI). MEPs recorded during motor imagery were compared to those recorded during a matched visual imagery task.


RESULTS
Imagined foot dorsiflexions increased MEP areas in both TA and FDI. The increase in TA was stronger than in FDI. Overall, imagined walking did not change MEP areas. However, subjects with larger increases in TA during imagined foot dorsiflexion also showed larger increases in TA during imagined walking.


CONCLUSIONS
Imagined foot dorsiflexions increase corticospinal excitability in both a task-related muscle (TA) and a task-unrelated muscle (FDI), with larger increases in the task-related muscle. Imagined gait only increases corticospinal excitability in those subjects with the largest increments during imagined foot dorsiflexion.


CONCLUSIONS
Imagery of a simple lower extremity movement evokes increases in corticospinal excitability. Furthermore, corticospinal effects of a simple motor imagery task can predict corticospinal effects of a more complex motor imagery task involving the same muscle.
Bakker
M
M
Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, The Netherlands.
Overeem
S
S
Snijders
A H
AH
Borm
G
G
van Elswijk
G
G
Toni
I
I
Bloem
B R
BR
D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D005385:Fingers / Q000294:innervation / Q000502:physiology; D005528:Foot; D005684:Gait / Q000502:physiology*; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance; D011712:Pyramidal Tracts / Q000502:physiology*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult