Skin conductance responses (SCRs) reliably occur in the absence of external stimulation. However, the neural correlates of these non-specific SCRs have been less explored than brain activity associated with stimulus-elicited SCRs. This study modeled spontaneous skin conductance responses observed during an unstructured resting state fMRI scan in 58 adolescents. A Finite Impulse Response (FIR) fMRI model was used to detect any type of hemodynamic response shape time-locked to non-specific SCRs; the shape of these responses was then carefully characterized. The strongest evidence for signal change was found in several sub-regions of sensorimotor cortex. There also was evidence for engagement of discrete areas within the lateral surfaces of the parietal lobe, cingulate cortex, fronto-insular operculum, and both visual and auditory primary processing areas. The hemodynamic profile measured by FIR modeling clearly resembled an event-related response. However, it was a complex response, best explained by two quickly successive, but opposing neuronal impulses across all brain regions - a brief positive response that begins several seconds prior to the SCR with a much longer negative neuronal impulse beginning shortly after the SCR onset. Post hoc exploratory analyses linked these two hemodynamic response phases to different emotion-related individual differences. In conclusion, this study shows the neural correlates of non-specific SCRs are a widespread, cortical network of brain regions engaged in a complex, seemingly biphasic fashion. This bimodal response profile should be considered in replication studies that attempt to directly link brain activity to possible homeostatic mechanisms or seek evidence for alternative mechanisms.

中文翻译：

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静息状态 fMRI 期间非特异性皮肤电导反应的神经相关性

在没有外部刺激的情况下，皮肤电导反应 (SCR) 会可靠地发生。然而，与刺激引发的 SCR 相关的大脑活动相比，对这些非特异性 SCR 的神经相关性的探索较少。该研究模拟了在 58 名青少年的非结构化静息状态 fMRI 扫描期间观察到的自发皮肤电导反应。有限脉冲响应 (FIR) fMRI 模型用于检测时间锁定到非特定 SCR 的任何类型的血流动力学响应形状；然后仔细表征这些反应的形状。在感觉运动皮层的几个子区域中发现了信号变化的最强证据。也有证据表明在顶叶、扣带回皮质、额岛岛盖、以及视觉和听觉初级处理区。通过 FIR 建模测量的血流动力学曲线明显类似于事件相关的反应。然而，这是一个复杂的反应，最好用跨越所有大脑区域的两个快速连续但相反的神经元冲动来解释——在 SCR 前几秒钟开始的短暂的积极反应，在 SCR 开始后不久开始出现更长的消极神经元冲动。事后探索性分析将这两个血流动力学反应阶段与不同的情绪相关个体差异联系起来。总之，这项研究表明，非特异性 SCR 的神经相关物是一种广泛存在的大脑区域皮质网络，以复杂的、看似双相的方式参与其中。