RT Journal Article
SR Electronic
T1 Dominance of ipsilateral corticospinal pathway in congenital mirror movements
JF Journal of Neurology, Neurosurgery & Psychiatry
JO J Neurol Neurosurg Psychiatry
FD BMJ Publishing Group Ltd
SP 276
OP 279
DO 10.1136/jnnp.2004.040949
VO 76
IS 2
A1 Y Ueki
A1 T Mima
A1 T Oga
A1 A Ikeda
A1 T Hitomi
A1 H Fukuyama
A1 T Nagamine
A1 H Shibasaki
YR 2005
UL http://jnnp.bmj.com/content/76/2/276.abstract
AB Objective: To clarify the mechanism of congenital mirror movements. Design: The triple stimulation technique (TST) and the silent period were used to investigate a patient with congenital mirror movements. The TST was used to calculate the ratio of ipsilateral to contralateral corticospinal tracts from the two hemispheres to the spinal motor neurones. Results: Transcranial magnetic stimulation over unilateral M1 induced larger ipsilateral than contralateral motor evoked potentials on both sides. Only 9% of spinal motor neurones innervating the abductor digitorum minimi were excited by contralateral primary motor cortex (M1) stimulation, while 94% were excited by the ipsilateral M1 stimulation. The silent period was examined during mirror movements and with voluntary contraction of the right first dorsal interosseus mimicking mirror movements. Left M1 stimulation (through the crossed corticospinal tract) did not show any difference in silent period between the two conditions, while right M1 stimulation (through the uncrossed tract) caused a longer silent period during mirror movements than during voluntary contractions. Conclusions: The results suggest that mirror movements may be caused by a strong connection between ipsilateral M1 and the mirror movements conveyed through a dominant ipsilateral corticospinal pathway.