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Somatosensory evoked magnetic fields (SEFs), corresponding with electrical median nerve stimulation, were measured using an MRI-linked, whole-head MEG system. In total 184 hemispheres, SEFs were measured, involving 22 normal volunteers and 70 patients with intracranial lesions. The first SEF peak appeared 20.2 +/- 1.5 msec (mean +/- S.D.) after stimulation.(More)
The present study examined 13 patients with typical left unilateral spatial neglect to explore the mechanisms of neglect in copying a single object. All patients identified the figure of a sunflower as a flower that had petals all around the central circle. Besides, in the free viewing of the flowers prepared by the examiner, 10 of the 13 patients could(More)
The abacus, a traditional physical calculation device, is still widely used in Asian countries. Previous behavioral work has shown that skilled abacus users perform rapid and precise mental arithmetic by manipulating a mental representation of an abacus, which is based on visual imagery. However, its neurophysiological basis remains unclear. Here, we report(More)
Three patients with unilateral spatial neglect could detect the difference of length between the right and left segments when a line had a transection mark. To examine the effect of response mode, the manual line bisection task and a new "line bisection task by fixation" were given to the patients. In tasks that used lines with no landmark, they showed(More)
We investigated the line bisection performances in 24 patients with left unilateral spatial neglect. They bisected lines of two lengths in three positions relative to the sagittal midplane of the body. The results showed that in the mild or moderate neglect patients, length and spatial locations of the lines affected the placement of the subjective(More)
OBJECTIVES To clarify the mechanisms of left unilateral spatial neglect found in the bisection of lines after cueing to the left end point and to determine whether neglect occurs for the mental representation of a line. METHODS A new representational bisection task was developed to eliminate the influence of the right segment of the physical line that(More)
Cube-copying is often used to assess constructional ability of brain-damaged patients and the influence of unilateral spatial neglect is often pointed out in patients with right hemisphere lesions. However, some patients with severe neglect perform cube-copying satisfactorily. The aim of the present study is to identify the factors that affect the(More)
In 20 healthy subjects, auditory evoked magnetic fields were measured over the entire head, using a helmet-shaped 66-channel MEG system linked to MRI. When the left or right ear was stimulated by 60 msec 2 kHz tones, the prominent 100 msec response (N100m) appeared significantly earlier in the contralateral hemisphere than in the ipsilateral one. In 16(More)