Kagawa Tomonori, Narita Noriyuki, Iwaki Sunao, Kawasaki Shingo, Kamiya Kazunobu, Minakuchi Shunsuke
Gerodontology and Oral Rehabilitation Department of Gerontology and Gerodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Department of Removable Prosthodontics, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
PLoS One. 2014 Oct 9;9(10):e108685. doi: 10.1371/journal.pone.0108685. eCollection 2014.
A cross-modal association between somatosensory tactile sensation and parietal and occipital activities during Braille reading was initially discovered in tests with blind subjects, with sighted and blindfolded healthy subjects used as controls. However, the neural background of oral stereognosis remains unclear. In the present study, we investigated whether the parietal and occipital cortices are activated during shape discrimination by the mouth using functional near-infrared spectroscopy (fNIRS). Following presentation of the test piece shape, a sham discrimination trial without the test pieces induced posterior parietal lobe (BA7), extrastriate cortex (BA18, BA19), and striate cortex (BA17) activation as compared with the rest session, while shape discrimination of the test pieces markedly activated those areas as compared with the rest session. Furthermore, shape discrimination of the test pieces specifically activated the posterior parietal cortex (precuneus/BA7), extrastriate cortex (BA18, 19), and striate cortex (BA17), as compared with sham sessions without a test piece. We concluded that oral tactile sensation is recognized through tactile/visual cross-modal substrates in the parietal and occipital cortices during shape discrimination by the mouth.
在盲文阅读过程中，体感触觉与顶叶和枕叶活动之间的跨模态关联最初是在对盲人受试者的测试中发现的，以视力正常和蒙眼的健康受试者作为对照。然而，口腔立体觉的神经背景仍不清楚。在本研究中，我们使用功能近红外光谱（fNIRS）研究了在通过口腔进行形状辨别时，顶叶和枕叶皮质是否被激活。在呈现测试片形状后，与静息状态相比，无测试片的假辨别试验诱导了顶叶后叶（BA7）、纹外皮质（BA18、BA19）和纹状皮质（BA17）的激活，而与静息状态相比，测试片的形状辨别显著激活了这些区域。此外，与无测试片的假试验相比，测试片的形状辨别特异性地激活了顶叶后皮质（楔前叶/BA7）、纹外皮质（BA18、19）和纹状皮质（BA17）。我们得出结论，在通过口腔进行形状辨别时，口腔触觉是通过顶叶和枕叶皮质中的触觉/视觉跨模态基质来识别的。
