[Stimulus time dependence of cerebral blood flow response to photic stimulation].
The time dependency of rCBF response to photic stimulation in the primary visual cortices was studied using H215O bolus-injection and PET. The subjects consisted of 5 normal volunteers aged from 25 to 40 years old. Their regional CBF was measured at 2 min and 7 min after the start of photic stimulation (frequency, 10 Hz). The percentage increases of rCBF were 19.6 +/- 7.9% (mean +/- SD, range: 8.9-27.6%) in the primary visual cortex on the left side and 23.2 +/- 13.6% (2.5-35.8%) on the right side at 2 min, respectively, while, in comparison, they were 25.3 +/- 20.0% (1.8-49.7%) on the left side and 25.3 +/- 16.4% (3.5-44.5%) on the right side at 7 min, respectively. No significant difference was found in the rCBF responses between at 2 min and 7 min. Therefore, the taming effect does not need to be considered when carrying out a photic stimulation study.
Kuwabara
Y
Y
Department of Radiology, Faculty of Medicine, Kyushu University, Fukuoka.
Ichiya
Y
Y
Otsuka
M
M
Sasaki
M
M
Akashi
Y
Y
Yoshida
T
T
Fukumura
T
T
Masuda
K
K
Ichimiya
A
A
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D006801:Humans; D010104:Oxygen Radioisotopes; D010775:Photic Stimulation; D013997:Time Factors; D014055:Tomography, Emission-Computed
D010104:Oxygen Radioisotopes