The peripersonal space (PPS) is a special portion of space immediately surrounding the body, where the integration between tactile stimuli delivered on the body and auditory or visual events emanating from the environment occurs. Interestingly, PPS can widen if a tool is employed to interact with objects in the far space. However, electrophysiological evidence of such tool-use dependent plasticity in the human brain is scarce. Here, in a series of three experiments, participants were asked to respond to tactile stimuli, delivered to their right hand, either in isolation (unimodal condition) or combined with auditory stimulation, which could occur near (bimodal-near) or far from the stimulated hand (bimodal-far). According to multisensory integration spatial rule, when bimodal stimuli are presented at the same location, we expected a response enhancement (response time – RT – facilitation and event-related potential – ERP – super-additivity). In Experiment 1, we verified that RT facilitation was driven by bimodal input spatial congruency, independently from auditory stimulus intensity. In Experiment 2, we showed that our bimodal task was effective in eliciting the magnification of ERPs in bimodal conditions, with significantly larger responses in the near as compared to far condition. In Experiment 3 (main experiment), we explored tool-use driven PPS plasticity. Our audio-tactile task was performed either following tool-use (a 20-min reaching task, performed using a 145 cm-long rake) or after a control cognitive training (a 20-min visual discrimination task) performed in the far space. Following the control training, faster RTs and greater super-additive ERPs were found in bimodal-near as compared to bimodal-far condition (replicating Experiment 2 results). Crucially, this far-near differential response was significantly reduced after tool-use. Altogether our results indicate a selective effect of tool-use remapping in extending the boundaries of PPS. The present finding might be considered as an electrophysiological evidence of tool-use dependent plasticity in the human brain.

人际空间 (PPS) 是紧邻身体的空间的特殊部分，身体上传递的触觉刺激与环境发出的听觉或视觉事件之间的整合发生在这里。有趣的是，如果使用工具与远处空间中的物体进行交互，PPS 可以扩大。然而，人脑中这种工具使用依赖性可塑性的电生理学证据很少。在这里，在一系列三个实验中，参与者被要求对触觉刺激做出反应，传递到他们的右手，无论是孤立的（单峰条件）还是与听觉刺激相结合，这可能发生在附近（双峰-近）或远离受刺激的手（双峰-远）。根据多感官整合空间规则，当双峰刺激出现在同一位置时，我们期望响应增强（响应时间 - RT - 促进和事件相关电位 - ERP - 超加性）。在实验 1 中，我们验证了 RT 促进是由双峰输入空间一致性驱动的，独立于听觉刺激强度。在实验 2 中，我们展示了我们的双峰任务在双峰条件下有效地引起 ERP 的放大，与远距离条件相比，近场响应明显更大。在实验 3（主要实验）中，我们探索了工具使用驱动的 PPS 可塑性。我们的听觉触觉任务是在使用工具后执行的（20 分钟的到达任务，使用 145 厘米长的耙子进行）或在远处空间进行控制认知训练（20 分钟的视觉辨别任务）之后进行。在控制训练之后，与双峰-远条件相比，在双峰-近中发现了更快的 RT 和更大的超加性 ERP（复制实验 2 结果）。至关重要的是，这种远近差异响应在使用工具后显着降低。总之，我们的结果表明工具使用重新映射在扩展 PPS 边界方面的选择性作用。目前的发现可能被认为是人脑中工具使用依赖性可塑性的电生理学证据。使用工具后，这种远近差异响应显着降低。总之，我们的结果表明工具使用重新映射在扩展 PPS 边界方面的选择性作用。目前的发现可能被认为是人脑中工具使用依赖性可塑性的电生理学证据。使用工具后，这种远近差异响应显着降低。总之，我们的结果表明工具使用重新映射在扩展 PPS 边界方面的选择性作用。目前的发现可能被认为是人脑中工具使用依赖性可塑性的电生理学证据。