Mapping visual field with positron emission tomography by mathematical modeling of the retinotopic organization in the calcarine cortex

Abstract

We developed an objective and quantitative method of mapping the human visual field with positron emission tomography (PET) and magnetic resonance image (MRI). The regional cerebral blood flow (rCBF) images were acquired with H2(15)O-PET under visual fixation as well as under visual stimulation with flickering diodes arranged along the ring at 0 degree, 3 degrees, 7 degrees, 14 degrees, 21 degrees, or 29 degrees from the fixation point. After coregistration of PET and MR images, we extracted the surface of the calcarine cortex from the MR images and unfolded it to a two-dimensional (2-D) elliptic plane, on which the activated PET images were superimposed. Then we transformed the unfolded calcarine cortex into the visual field coordinates using the complex logarithmic function proposed by Schwartz. A large individual variation was observed in the retinotopical organization as well as in the morphology of the calcarine cortex. The formula was valid only within 15 degrees from the center of the visual field. The constant parameter in the formula was estimated to be 1.5. The cortical linear magnification factor was 12.1, 2.8, and 1.6 at 0, 5, and 10 degrees, respectively. The areas of the central 10 degrees and 40 degrees in the visual field correspond to 50% and 81% of the calcarine surface, respectively.

Frequency-Following and Connectivity of Different Visual Areas in Response to Contrast-Reversal Stimulation

“…Aine et al (1995Aine et al ( , 1996 described significant differences in visual waveforms from variation in the structure of the calcarine fissure, as well as significant differences in retinotopic maps about the calcarine fissure between subjects. Endo et al (1997) confirmed both the anatomical and functional variability of the primary visual area in a PET retinotopy study. Second, the nonoscillatory responses in some of the waveforms may indicate conditions where the frequency-following areas were relatively close anatomically but temporally out of phase with each other, thereby canceling out the oscillatory behavior in the waveforms.…”

Gender differences in cerebral metabolism for color processing in mice: A PET/MRI Study

“…In recent years, functional imaging studies have been performed in humans to explore these projections in living subjects with magnetic resonance imaging (MRI) [8–10], high-density diffuse optical tomography [11] or positron emission tomography (PET) [12,13]. Despite this, physiological studies of gender-related differences in color processing in humans are rare.…”

Cerebral glucose metabolism in the striate cortex positively correlates with fractional anisotropy values of the optic radiation in patients with glaucoma

“…We used the 30‐2 program of the Humphrey Visual Field Analyzer to target the visual field within 30° from the centre. The fovea is represented by the occipital pole of the hemisphere, and the central 30° of the visual field corresponds to approximately 80% of the striate cortex . The correlations between the glucose metabolism in the whole striate cortex and the average of the total deviations within 30° of the visual field were lower than those between the posterior striate cortex and 10° of the visual field.…”