Detection of visual activation of lateral geniculate nucleus by positron emission tomography.
OBJECTIVE
Although activation of the lateral geniculate nucleus (LGN) has been shown by functional magnetic resonance imaging, a quantitative evaluation of the activity has not been reported by positron emission tomography (PET). The purpose of this study was to quantify the degree of activation of the LGN and other vision-related structures by visual stimuli as detected by PET.


METHODS
PET activation was induced by a bolus injection of 15O-labelled water (H2(15)O) in six normal volunteers. The regional cerebral blood flow (rCBF) was measured under three conditions: eyes closed, binocular flickering light stimulation, and binocular viewing of a video movie. Single-subject analysis, group analysis, and correlation analysis were performed.


RESULTS
Although single-subject analysis did not show significant changes, group analysis revealed a significant increase in rCBF in the left LGN induced by flickering light stimulation ( P<0.01) and video stimulation ( P<0.05). Localization of the activation foci in the LGN agreed with the retinotopic organization of the LGN.


CONCLUSIONS
Although the LGN is relatively small compared with the resolution of the PET image, visually activated blood flow changes could be determined by H2(15)O PET:
Mizoguchi
Shoichi
S
Department of Ophthalmology and Visual Science, School of Medicine, Tokyo Medical and Dental University, Yushima 1-chome 5-45, Bunkyo-ku, Tokyo 113-8519, Japan.
Suzuki
Yukihisa
Y
Kiyosawa
Motohiro
M
Mochizuki
Manabu
M
Kawasaki
Tsutomu
T
Ishii
Kenji
K
Senda
Michio
M
D000328:Adult; D001921:Brain / Q000098:blood supply; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005829:Geniculate Bodies / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D010104:Oxygen Radioisotopes; D010775:Photic Stimulation; D014055:Tomography, Emission-Computed; D014793:Visual Cortex / Q000000981:diagnostic imaging / Q000502:physiology*
D010104:Oxygen Radioisotopes