Location of Primary Motor Cortex Function in Cerebral Migration Disorder

Abstract

Purpose : The purpose of this study was to demonstrate by functional MRI (fMRI) the location of the primary motor cortex in patients with schizencephaly Materials and Methods : fMRI was performed in four patients with schizencephaly who complained of seizures; three were right handed and one was ambidextrous. Associated lesions were agenesis of the corpus callosum in one patient and absence of the septum pellucidum in another. fMRI employed the single sliced FLASH BOLD technique using a 1. 5-T MR imager with a standard head coil, and was obtained in the axial plane. Thirty consecutive images were obtained on finger movements of each hand were obtained ; the motor task consisted ofrepetitive finger to thumb opposition. Percentage change in primary motor cortex signal intensity was calculated, and ipsilateral activation index was compared between the affected and unaffected hemispheres.Results : Percentage change in signal intensity increase in the activated area of the unaffected hemisphere ranged from 4.8 % :t 0.9 % to 9.2 :t 1.2 % (mean : 5.6 % :t 1. 5 %) of the baseline value. The ipsilateral activation index of the affected hemisphere was 0 -0.38 and that of the unaffected hemisphere was 15 .4 ∞ ; in patients with schizencephaly significantly different{p < 0.01).Conclusion : Our results suggest that increased activation in the unaffected hemisphere reflect functional reorganization ofthe primary motor cortex. Index words: Magnetic resonance(MR), technologyBrain, abnormalitiesFunctional MRI (fMRI) can demonstrate reorganization of the functioning primary motor cortex area(l) The location of the functioning cortex may be altered by plasticity of the brain, the process by which neurons in normal regions of the brain take over functions in regions in which damage or disease has been caused by acquired brain lesions such as infarction or brain tumor(l -5). Even in congenital brain lesions, this process occurs. The purpose ofthis study was to report this process, as seen on fMRI, in schizen Materials and MethodsfMRI of the primary motor cortex was performed in four schizencephalic patients who complained of seizure(male : female = 3: 1, mean age: 23 , 5years). Associated lesions were agenesis of the corpus callosum in one patient and absence of the septum pellucidum in another; three were right handed and one was ambidextrous, MR imaging was performed on a 1, 5-T Magnetom Vision system(Siemens AG, Erlangen, Germany), using a standard head coil. Tl weighted anatomical images were obtained in the tilted axial plane through the primary motor cortex. Using a single sliced FLASH (fast low-angle shot) BOLD (blood oxygen level dependent) technique, fMRI was performed , For each image, m …