The "mirror-neuron system" in MS: A 3 tesla fMRI study.
OBJECTIVE
The mirror neuron system (MNS) is an observation-execution matching system activated, in humans, during action observation, motor learning, and imitation of action. We used functional MRI (fMRI) to investigate the properties of the MNS in patients with multiple sclerosis (MS).


METHODS
Using a 3 tesla scanner, we acquired fMRI in 16 right-handed patients with relapsing-remitting MS and 14 controls. Two motor tasks were studied. The first consisted of repetitive flexion-extension of the last four fingers of the right hand (simple task) alternated to epochs of rest; the second (MNS task) consisted of observation of a movie showing the hand of another subject while performing the same task.


RESULTS
During the simple task, compared to controls, patients with MS had more significant activations of the contralateral primary sensorimotor cortex and supplementary motor area. During the MNS task, both groups showed the activation of several visual areas, the infraparietal sulcus, and the inferior frontal gyrus (IFG), bilaterally. The IFG and the visual areas were significantly more active in patients than controls. The between-group interaction analysis showed that in patients with MS, part of the regions of the MNS were more active also during the simple task.


CONCLUSIONS
This study suggests increased activation of the mirror neuron system in patients with multiple sclerosis (MS) with a normal level of function and widespread CNS damage. The potentialities of this system in facilitating clinical recovery in patients with MS and other neurologic conditions should be investigated.
Rocca
M A
MA
Neuroimaging Research Unit, Department of Neurology, Scientific Institute and University Ospedale San Raffaele, Via Olgettina, 60, 20132 Milan, Italy.
Tortorella
P
P
Ceccarelli
A
A
Falini
A
A
Tango
D
D
Scotti
G
G
Comi
G
G
Filippi
M
M
D000328:Adult; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D004185:Disability Evaluation; D005260:Female; D005385:Fingers / Q000294:innervation / Q000503:physiopathology; D006801:Humans; D007100:Imitative Behavior / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000503:physiopathology*; D009415:Nerve Net / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D009474:Neurons / Q000502:physiology; D009483:Neuropsychological Tests / Q000592:standards; D011237:Predictive Value of Tests; D011597:Psychomotor Performance / Q000502:physiology; D012680:Sensitivity and Specificity