Erschienen in:
01.06.2005 | Clinical Investigation
Differential activation of cerebral blood flow by stimulating amblyopic and fellow eye
verfasst von:
Shoichi Mizoguchi, Yukihisa Suzuki, Motohiro Kiyosawa, Manabu Mochizuki, Kenji Ishii
Erschienen in:
Graefe's Archive for Clinical and Experimental Ophthalmology
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Ausgabe 6/2005
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Abstract
Purpose
Positron emission tomography (PET), the blood flow response in the primary visual cortex (V1) to two visual stimuli, low temporal frequency (6 Hz) to activate the parvocellular system, and high temporal frequency (25 Hz) to activate the magnocellular system were used to investigate pathophysiologic mechanism of amblyopia.
Methods
Five women and one man who were aged between 26 and 60 years, who were ophthalmologically normal except for amblyopia, and who had corrected visual acuity in the amblyopic eye of 0.6 or worse were examined. An intravenous injection of the H215O was given, and the regional cerebral blood flow was measured by PET during full-field stimulation with either 6 Hz or 25 Hz flicker to the amblyopic or the sound eye.
Result
The activation of blood flow in the contra-lateral area V1 by the 6-Hz stimulation of the sound eye was greater than that during the stimulation of the amblyopic eye (P<0.05, small volume correction, n=6). With 25-Hz stimulation of the sound and amblyopic eyes, the blood flow in the contra-lateral and ipsi-lateral areas V1 was not significantly different.
Conclusion
The decreased activation of blood flow in the contra-lateral V1 by low temporal frequency stimuli supports the hypothesis that the parvocellular pathway in amblyopic eyes is depressed.