Functional mapping of the human colour centre with echo-planar magnetic resonance imaging.
Clinical studies of cerebral achromatopsia have suggested a colour centre in the human fusiform gyrus. By using functional magnetic resonance imaging, we examined whether the fusiform gyrus shows activity correlated with the perception of colour. We tested three stimulus conditions in which the subject maintained fixation: (i) a circular array of six coloured circles; (ii) the same as (i) except that each circle is equiluminant grey with its colour counterpart; and (iii) the same as (i) plus a clockwise shift of circles to neighbouring positions every 1 s. After termination of the stimulus, the subject perceived an after-image of circles with complementary colours in (i), but not in (iii). In condition (i), we found a focal signal increase in the posterior part of the fusiform gyrus. In condition (ii), the activation in the same locus during the stimulation period was weaker than that in (i). In condition (iii), the signal intensity after termination of the stimulus was weaker than that in (i). The colour effect and after-effect on activation of the fusiform gyrus observed here suggest its critical role in human colour perception.
Sakai
K
K
Department of Physiology, School of Medicine, University of Tokyo, Japan.
Watanabe
E
E
Onodera
Y
Y
Uchida
I
I
Kato
H
H
Yamamoto
E
E
Koizumi
H
H
Miyashita
Y
Y
D001931:Brain Mapping / Q000379:methods*; D003118:Color Perception / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000033:anatomy & histology* / Q000502:physiology*; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D014794:Visual Fields