Abstract
[Purpose] The aim of this study was to investigate which of cortical areas are precisely involved in performing the two-point discrimination task (TPD), using functional magnetic resonance image (fMRI). [Subjects and Methods] Nine healthy right-handed subjects were recruited. During fMRI scanning, tactile sensory stimulation of one- or two-points was conducted on the dominant thumb with a two-point discriminator. At that time, The subject pressed a corresponding button when perceived one point or two points, corresponding to the two types of delivered tactile stimulation. [Results] In group analysis, the averaged cortical maps showed that the left and right primary sensory cortices and inferior parietal cortices were activated. In the bilateral primary sensory cortex, the peak intensities were 7.34 and 5.14, in the left and right hemispheres, respectively. In addition, the left and right inferior parietal cortices were activated, and the peak intensities were 4.30 and 6.18, respectively. [Conclusion] Our results revealed that the performance of a TPD task is likely to require the higher order sensory discriminative modality which is processed by the cortical cognitive function. In addition, the neural processing of TPD was specifically associated with bilateral activity in the inferior parietal cortex.
