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Abstract
Background and aims Brain cortex controls movement but the influence of peripheral component of movement on cortex is not known. functional magnetic resonance imaging(fMRI) studies in volenteers, investigate cortex areas activated during execution and imagination of complex movements.
We hypothesized that cortex areas activated to remember, organize and order to do a movement can be isolated from areas activated during performing the motor component of movement when the limb is peripherally blocked. We also aimed to show if there is bilateral cortex activity during acute peripheral motor block as seen in stroke patients and amputated patients.
Methods We performed brain fMRI in 3 right-handed patients scheduled to undergo right-hand surgery with peripheral block anaesthesia as a pilot-study. Ethics approval and written informed consent from all patients were obtained. fMRI screening was performed before the surgery day and just before surgery after the block. Patients were screened when executing the task (figure 1) (after the block they just attempt), during rest and during they imagine doing the task.
Results The activation areas decreased after right-hand block during both blocked and intact hand execution trials (figure 2) and imagination trials (figure 3). We propose that the difference between the areas of right hand represent the motor component of movement.
A) Right hand move; B) Post-block right hand efforting to move (no motion is observed in the right hand); C) Left hand move; D) Post-block (of right hand) left hand move
A) Right hand imagine; B) Post-block right hand imagine; C) Left hand imagine; D) Post-block(right hand) left hand imagine; (no motion is observed in both hands in all trails
Conclusions In this report, we describe a model that shows the activation areas during the effort of execution and imagery of complex hand movements during peripheral-nerve-block. There are many unknowns in the interactions between the brain-peripheral organ during movement. Identification of motor activation areas will help to perform more effective stroke rehabilitation and neurophatic pain therapies.