Recent literature suggests that the primary somatosensory cortex (S1), once thought to be a low-level area only modality-specific, is also involved in higher-level, cross-modal, cognitive functions. In particular, electrophysiological studies have highlighted that the cross-modal activation of this area may also extend to visual Working Memory (WM), being part of a mnemonic network specific for the temporary storage and manipulation of visual information concerning bodies and body-related actions. However, the causal recruitment of S1 in the WM network remains speculation.

In the present study, by taking advantage of repetitive Transcranial Magnetic Stimulation (rTMS), we look for causal evidence that S1 is implicated in the retention of visual stimuli that are salient for this cortical area. To this purpose, in a first experiment, high-frequency (10 Hz) rTMS was delivered over S1 of the right hemisphere, and over two control sites, the right lateral occipital cortex (LOC) and the right dorsolateral prefrontal cortex (dlPFC), during the maintenance phase of a high-load delayed match-to-sample task in which body-related visual stimuli (non-symbolic hand gestures) have to be retained. In a second experiment, the specificity of S1 recruitment was deepened by using a version of the delayed match-to-sample task in which visual stimuli depict geometrical shapes (non-body related stimuli).

Results show that rTMS perturbation of S1 activity leads to an enhancement of participants’ performance that is selective for body-related visual stimuli; instead, the stimulation of the right LOC and dlPFC does not affect the temporary storage of body-related visual stimuli. These findings suggest that S1 may be recruited in visual WM when information to store (and recall) is salient for this area, corroborating models which suggest the existence of a dedicated mnemonic system for body-related information in which also somatosensory cortices play a key role, likely thanks to their cross-modal (visuo-tactile) properties.

最近的文献表明，初级躯体感觉皮层 (S1)，曾经被认为是一个低层次的区域，只有特定于模态的区域，也参与了更高层次的、跨模态的认知功能。特别是，电生理学研究强调，该区域的跨模式激活也可能扩展到视觉工作记忆 (WM)，它是记忆网络的一部分，专门用于临时存储和操纵有关身体和身体相关动作的视觉信息. 然而，WM 网络中 S1 的因果招募仍然是猜测。

在本研究中，通过利用重复经颅磁刺激 (rTMS)，我们寻找因果证据，证明 S1 与保留对这个皮质区域很重要的视觉刺激有关。为此，在第一个实验中，高频 (10 Hz) rTMS 被传递到右半球的 S1 和两个控制部位，右侧枕叶皮层 (LOC) 和右侧背外侧前额叶皮层 (dlPFC)，在高负载延迟匹配样本任务的维护阶段，其中必须保留与身体相关的视觉刺激（非符号手势）。在第二个实验中，S1 招募的特异性通过使用延迟匹配到样本任务的版本而加深，其中视觉刺激描绘几何形状（与身体无关的刺激）。

结果表明，对 S1 活动的 rTMS 扰动可提高参与者对身体相关视觉刺激的选择性；相反，对右侧 LOC 和 dlPFC 的刺激不影响与身体相关的视觉刺激的临时存储。这些发现表明，当要存储（和回忆）的信息对该区域很重要时，S1 可能会在视觉 WM 中被招募，证实了模型，这些模型表明存在一个专门的记忆系统，用于身体相关信息，其中体感皮层也起着关键作用，可能要归功于它们的跨模态（视觉触觉）特性。