[Functional magnetic resonance imaging of the human primary visual cortex during visual stimulation].
Signal changes in the human primary visual cortex during visual stimulation were evaluated using non-invasive functional magnetic resonance imaging (fMRI). The experiments were performed on 10 normal human volunteers and 2 patients with homonymous hemianopsia, including one who was recovering from the exacerbation of multiple sclerosis. The visual stimuli were provided by a pattern generator using the checkerboard pattern for determining the visual evoked potential of full-field and hemifield stimulation. In normal volunteers, a signal increase was observed on the bilateral primary visual cortex during the full-field stimulation and on the contra-lateral cortex during hemifield stimulation. In the patient with homonymous hemianopsia after cerebral infarction, the signal change was clearly decreased on the affected side. In the other patient, the one recovering from multiple sclerosis with an almost normal visual field, the fMRI was within normal limits. These results suggest that it is possible to visualize the activation of the visual cortex during visual stimulation, and that there is a possibility of using this test as an objective method of visual field examination.
Miki
A
A
Department of Ophthalmology, Niigata University School of Medicine, Japan.
Nakajima
T
T
Fujita
M
M
Watanabe
H
H
Kuwabara
T
T
Naruse
S
S
Takagi
M
M
Abe
H
H
D000328:Adult; D005260:Female; D006423:Hemianopsia / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D014793:Visual Cortex / Q000033:anatomy & histology*; D014794:Visual Fields