MEG recording from the human ventro-occipital cortex in response to isoluminant color stimulation.
In contrast to PET and fMRI studies, color-selective responses from the ventro-occipital area have rarely been reported in MEG studies. We tried to minimize the stimulation to all areas in the visual system except the color-processing ones by using a color space based on psychophysical and physiological knowledge in order to maximize the signal-to-noise ratio for MEG responses from the ventro-occipital area. MEG obtained from long intermittent reversals (2.0-3.5 s) of isoluminant chromatic gratings showed two major peaks at the latencies of approximately 100 and 150 ms. The estimated location of the equivalent-current dipole for response at 100-ms latency was in the calcarine sulcus and that of the dipole for the response at 150 ms was in the collateral sulcus in the ventro-occipital area. The response around 150 ms was uniquely observed in MEG elicited by chromatic reversals. The average of lags between MEG responses from the calcarine sulcus and ventro-occipital area was 43 ms, which suggests sequential processing of color information across the visual cortices.
Kuriki
Ichiro
I
Human and Information Science Laboratory, NTT Communication Science Laboratories, Kanagawa, Japan. ikuriki@brl.ntt.co.jp
Sadamoto
Kenji
K
Takeda
Tsunehiro
T
D000328:Adult; D001931:Brain Mapping; D003116:Color; D003118:Color Perception / Q000502:physiology*; D004307:Dose-Response Relationship, Radiation; D005074:Evoked Potentials, Visual / Q000502:physiology* / Q000528:radiation effects; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D009778:Occipital Lobe / Q000098:blood supply / Q000502:physiology* / Q000528:radiation effects; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation / Q000379:methods; D013028:Space Perception / Q000502:physiology; D013997:Time Factors; D014795:Visual Pathways / Q000502:physiology
D010100:Oxygen