抄録
In the previous study we reported that detection of color is dominant in the right hemisphere. Here we examined cerebral lateralization of color discrimination using reaction time (RT) task. Eighteen undergraduate students with normal vision (21-27 years old) were asked to press a key to a target color stimulus which was presented on a CRT. Two discriminative RT tasks were performed. In the first task, one of three color stimuli (2 deg in size, red 635 mm, green 535 mm and blue 445 mm) was presented either right or left visual field at 4 deg holizontally from a fixation point. Subjects were required to press a key with their ipsilateral hand to a target color, which was instructed previously. In the second one, a pair of color stimuli was presented either right or left visual field and subjects were required to press a key when the two stimuli were different. In the first experiment, the left hemisphere was found to be faster than the right hemisphere (367.2±21.0 ms vs. 385.6±21.2 ms). Similar results were obtained in the second experiment. Discrimination time, which was obtained by subtracting simple RT from discriminative RT was faster in the left hemisphere than the right hemisphere (121.4±10.3 ms vs. 150.3±20.0 ms). On the other hand, there was no significant difference between right and left hemisphere in the RT to achromatic targets. These findings seem to suggest that color discrimination is processed in the left hemisphere. [Jpn J Physiol 54 Suppl:S192 (2004)]
