Asymmetric activation to the context-dependent right in the right inferior frontal region.
In human spatial recognition, right and left are not recognized symmetrically. Although there have been many studies on the hemispheric asymmetry of the human brain, asymmetries in high-level recognition (such as independence from input or output hemisphere) have not been studied extensively. We found that the human brain recognizes right and left asymmetrically in high-level recognition. Experiments were performed in which participants crossed their hands and were required to judge the side of a tactile stimulus on the index finger in two different contexts: 'which hand was touched' or 'on which side of the space the touched hand was located'. The right inferior frontal region was significantly more activated by the 'contextually defined right' stimulus (right-hand stimulation in the 'which hand' context and right-space stimulation in the 'which space' context) than by the 'contextually defined left' stimulus. However, no activation that was more activated by the 'contextually defined left' than by the 'contextually defined right' was found. This asymmetric activation suggests that 'right' is the more outstanding side for human spatial recognition.
Misaki
Masaya
M
Brain Information Group, Kansai Advanced Research Center, Communications Research Laboratory, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe-shi, Hyogo. 651-2429, Japan. misaki@po.crl.go.jp
Matsumoto
Eriko
E
Miyauchi
Satoru
S
D000328:Adult; D001921:Brain / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D021641:Recognition, Psychology / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*; D014110:Touch / Q000502:physiology*