While detecting somatic stimuli from the external environment, an accurate determination of their spatial and temporal properties is essential for human behavior. Whether and how detection relates to human capacity for somatosensory spatial discrimination (SD) and temporal discrimination (TD) remains unclear. Here, participants underwent functional magnetic resonance imaging scanning when simply detecting vibrotactile stimuli of the leg, judging their location (SD), or deciding their number in time (TD). By conceptualizing tactile discrimination as consisting of detection and determination processes, we found that tactile detection elicited activation specifically involved in SD within the right inferior and superior parietal lobules, 2 regions previously implicated in the control of spatial attention. These 2 regions remained activated in the determination process, during which functional connectivity between these 2 regions predicted individual SD ability. In contrast, tactile detection produced little activation specifically related to TD. Participants’ TD ability was implemented in brain regions implicated in coding temporal structures of somatic stimuli (primary somatosensory cortex) and time estimation (anterior cingulate, pre-supplementary motor area, and putamen). Together, our findings indicate a close link between somatosensory detection and SD (but not TD) at the neural level, which aids in explaining why we can promptly respond toward detected somatic stimuli.

中文翻译：

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人类体感时空辨别的神经基础：感官检测的作用

在检测来自外部环境的体细胞刺激时，准确确定它们的空间和时间特性对于人类行为至关重要。检测是否以及如何与人类的体感空间辨别 (SD) 和时间辨别 (TD) 能力相关仍不清楚。在这里，参与者在简单地检测腿部的振动触觉刺激、判断他们的位置 (SD) 或确定他们的时间数量 (TD) 时接受了功能性磁共振成像扫描。通过将触觉辨别概念化为由检测和确定过程组成，我们发现触觉检测引发了在右下顶叶和上顶叶内特别涉及 SD 的激活，这两个区域以前涉及空间注意力的控制。这两个区域在确定过程中保持激活状态，在此期间这两个区域之间的功能连接预测了个体 SD 能力。相比之下，触觉检测几乎没有产生与 TD 相关的激活。参与者的 TD 能力在涉及编码体细胞刺激（初级体感皮层）的时间结构和时间估计（前扣带回、前补充运动区和壳核）的大脑区域中实施。总之，我们的研究结果表明，体感检测与神经水平的 SD（但不是 TD）之间存在密切联系，这有助于解释为什么我们可以迅速对检测到的体细胞刺激做出反应。触觉检测几乎没有产生与 TD 相关的激活。参与者的 TD 能力在涉及编码体细胞刺激（初级体感皮层）的时间结构和时间估计（前扣带回、前补充运动区和壳核）的大脑区域中实施。总之，我们的研究结果表明，体感检测与神经水平的 SD（但不是 TD）之间存在密切联系，这有助于解释为什么我们可以迅速对检测到的体细胞刺激做出反应。触觉检测几乎没有产生与 TD 相关的激活。参与者的 TD 能力在涉及编码体细胞刺激（初级体感皮层）的时间结构和时间估计（前扣带回、前补充运动区和壳核）的大脑区域中实施。总之，我们的研究结果表明，体感检测与神经水平的 SD（但不是 TD）之间存在密切联系，这有助于解释为什么我们可以迅速对检测到的体细胞刺激做出反应。