| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2004: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
Purpose : The presence of a lateralization, of cerebral hemispheric function concerning a memory was studied in normal subjects using functional MRI (fMRI), with its clinical application in epilepsy.
Methods : Subjects were 39 normal adult subjects and 13 patients with partial epilepsies. Out of the 39 normal subjects, 30 were right-handed and 9 were left-handed. Further, 12 of the 13 patients were right-handed and one was left-handed. Out of the 13 patients, 9, 3 and 1 had temporal lobe, frontal lobe and undetermined partial epilepsies, respectively. Three type of memory tasks; covert and overt recall tests of 10 words given auditorily and recall test of 6 figures given visually were designed. Cerebral areas activated during these tasks were imaged with f-MRI using 1.5tesla Magnetom Vision.
Results : Most of the 30 right-handed normal subjects showed activated areas mainly in the anterior cingulate,. superior., middle and inferior frontal gyri in the left cerebral hemisphere during the
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verbal covert recall tests. In addition, the left precentral gyri were activated during the verbal overt recall tests. Four of the 9 left-handed normal subjects showed the left side-dominant activation during the verbal covert and overt tests, in common with most of the right-handed normal subjects. However, the other 3 left-handed normal subjects had right side-dominant activation during the verbal memory tasks, whereas none of the 30 right-handed normal subjects showed such right side-dominant activation. Further, the bilateral occipital lobes were activated during the visual memory tasks. These activation during the verbal and visual memory tasks was excellently reproduced in fMRI re-examined after more than one years. Also in the epileptic patients, most of the 12 right-handed cases showed the left side-dominant activation during the verbal memory tasks, regardless of the laterality of epileptic foci. However, two right-handed patients having epileptic attacks at less than 5 years old and epileptic foci in the left frontal and temporal lobes, respectively, showed the right side-dominant activation during the verbal memory tasks. Further, one left-handed patient having an epileptic focus in the left frontal lobe showed the right side-dominant activation.
Conclusion : These results suggest that the medial frontal lobe including the anterior cingulate and superior frontal gyri, middle and inferior frontal gyri are probably related to a recall process in verbal memory function and further that the lateralization of cerebral hemispheric function in a memory exists in relation with a handedness. However, in epileptic patients having epileptic attacks at less than 5 years old, the memory lateralization may shift to the hemispheric side opposite to one related to the handedness as a change in a neuronal plasticity against an epileptic focus. f-MRI is an useful tool in preoperative evaluation of the lateralization of the cerebral hemispheric function dominant in a memory in surgical treatment of epilepsy. Less
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