Increased regional cerebral blood flow but normal distribution of GABAA receptor in the visual cortex of subjects with early-onset blindness.
Before the completion of visual development, visual deprivation impairs synaptic elimination in the visual cortex. The purpose of this study was to determine whether the distribution of central benzodiazepine receptor (BZR) is also altered in the visual cortex in subjects with early-onset blindness. Positron emission tomography was carried out with [(15)O]water and [(11)C]flumazenil on six blind subjects and seven sighted controls at rest. We found that the CBF was significantly higher in the visual cortex for the early-onset blind subjects than for the sighted control subjects. However, there was no significant difference in the BZR distribution in the visual cortex for the subject with early-onset blindness than for the sighted control subjects. These results demonstrated that early visual deprivation does not affect the distribution of GABA(A) receptors in the visual cortex with the sensitivity of our measurements. Synaptic elimination may be independent of visual experience in the GABAergic system of the human visual cortex during visual development.
Mishina
Masahiro
M
Department of Neurology, Neurological Institute, Nippon Medical School Chiba-Hokusoh Hospital, Inba, Japan. mishina@nms.ac.jp
Senda
Michio
M
Kiyosawa
Motohiro
M
Ishiwata
Kiichi
K
De Volder
Anne G
AG
Nakano
Hideki
H
Toyama
Hinako
H
Oda
Kei-ichi
K
Kimura
Yuichi
Y
Ishii
Kenji
K
Sasaki
Touru
T
Ohyama
Masashi
M
Komaba
Yuichi
Y
Kobayashi
Shirou
S
Kitamura
Shin
S
Katayama
Yasuo
Y
D000328:Adult; D017668:Age of Onset; D001766:Blindness / Q000453:epidemiology* / Q000503:physiopathology*; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011963:Receptors, GABA-A / Q000378:metabolism*; D014055:Tomography, Emission-Computed; D014793:Visual Cortex / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology
D011963:Receptors, GABA-A