Kitada Ryo, Hashimoto Toshihiro, Kochiyama Takanori, Kito Tomonori, Okada Tomohisa, Matsumura Michikazu, Lederman Susan J, Sadato Norihiro
Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan.
Neuroimage. 2005 Mar;25(1):90-100. doi: 10.1016/j.neuroimage.2004.11.026. Epub 2004 Dec 23.
Human subjects can tactually estimate the magnitude of surface roughness. Although many psychophysical and neurophysiological experiments have elucidated the peripheral neural mechanisms that underlie tactile roughness estimation, the associated cortical mechanisms are not well understood. To identify the brain regions responsible for the tactile estimation of surface roughness, we used functional magnetic resonance imaging (fMRI). We utilized a combination of categorical (subtraction) and parametric factorial approaches wherein roughness was varied during both the task and its control. Fourteen human subjects performed a tactile roughness-estimation task and received the identical tactile stimulation without estimation (no-estimation task). The bilateral parietal operculum (PO), insula and right lateral prefrontal cortex showed roughness-related activation. The bilateral PO and insula showed activation during the no-estimation task, and hence might represent the sensory-based processing during roughness estimation. By contrast, the right prefrontal cortex is more related to the cognitive processing, as there was activation during the estimation task compared with the no-estimation task, but little activation was observed during the no-estimation task in comparison with rest. The lateral prefrontal area might play an important cognitive role in tactile estimation of surface roughness, whereas the PO and insula might be involved in the sensory processing that is important for estimating surface roughness.
人类受试者能够通过触觉估计表面粗糙度的大小。尽管许多心理物理学和神经生理学实验已经阐明了触觉粗糙度估计背后的外周神经机制，但相关的皮层机制仍未得到很好的理解。为了确定负责触觉估计表面粗糙度的脑区，我们使用了功能磁共振成像（fMRI）。我们采用了分类（减法）和参数因子方法的组合，其中粗糙度在任务及其对照过程中均有所变化。14名人类受试者执行了一项触觉粗糙度估计任务，并在没有估计的情况下接受了相同的触觉刺激（无估计任务）。双侧顶叶岛盖部（PO）、脑岛和右侧前额叶皮层表现出与粗糙度相关的激活。双侧PO和脑岛在无估计任务期间显示出激活，因此可能代表粗糙度估计过程中基于感觉的处理。相比之下，右侧前额叶皮层与认知处理的关系更大，因为与无估计任务相比，估计任务期间有激活，但与静息状态相比，无估计任务期间观察到的激活很少。外侧前额叶区域可能在触觉估计表面粗糙度中发挥重要的认知作用，而PO和脑岛可能参与了对估计表面粗糙度很重要的感觉处理。
