| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1989: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Eye movement related cortical potentials were investigated in 23 normals, 13 patients with Parkinson's disease and 15 patients with various neurological diseases.
Scalp electrodes were placed according to the international 10-20 system. Electroencephalogram and electrooculogram were simultaneously recorded. Scalp potentials were averaged from 2.8 msec before to 1.2 msec after the trigger point by manually triggering at the onset of eye movement.
Subjects repeated horizontal saccade of 10ﾟ at an irregular interval around several seconds under 4 conditions. Thus, visually triggered saccade(VTS), auditory triggered saccade(ATS), self-paced voluntary saccade(VS)and self-paced voluntary saccade in darkness(VSD)were induced. For normal subjects, 1 to 3 of those 4 tasks were performed, while, patients performed only two tasks of VTS and VS.
As a result, I)Presaccadic slow negativity(PSN)began 1.8 sec before the onset of saccade and had the maximum amplitude at the Cz. The amplitude of the PSN wa
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s larger on the task which required more voluntary effort, such as VS and VSD than tasks which required less voluntary effort such as VTS and ATS. The PSN was thought to be a readiness potential, 2)The presaccadic slow positivity started 90-170 msec before the onset of saccade. The PSN began later in VSD. The result was in agreement with the hypothesis in which the PSN is related to processing of visual information, 3)The spike potential appeared at the onset of saccade. This potential may come from the ocular muscles, 4)The latency of lambdaPotential was the longest in VSD and the shortest in VTS. In contrast, the amplitude of lambda potential was the largest in VTS and the smallest in VSD. The lambda potential was thought to be visual evoked potential, 5)On rightor left- directed saccades, there was marked asymmetry of the amplitude of the PSN on occipital and frontal eye field areas. The PSN appeared on occipital area may represent readiness potential for visual perception.
In VS of patients with Parkinson's disease, the PSN appeared significantly less frequently than normals who always had the PSN.
Characteristics of the PSN in patients with cerebellar lesion and patients with lesions in the unilateral oculomotor pathway were inconclusive. Less
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