fMRI Scanner Noise Interaction with Affective Neural Processes

The purpose of the present study was the investigation of interaction effects between functional MRI scanner noise and affective neural processes. Stimuli comprised of psychoacoustically balanced musical pieces, expressing three different emotions (fear, neutral, joy). Participants (N=34, 19 female) were split into two groups, one subjected to continuous scanning and another subjected to sparse temporal scanning that features decreased scanner noise. Tests for interaction effects between scanning group (sparse/quieter vs continuous/noisier) and emotion (fear, neutral, joy) were performed. Results revealed interactions between the affective expression of stimuli and scanning group localized in bilateral auditory cortex, insula and visual cortex (calcarine sulcus). Post-hoc comparisons revealed that during sparse scanning, but not during continuous scanning, BOLD signals were significantly stronger for joy than for fear, as well as stronger for fear than for neutral in bilateral auditory cortex. During continuous scanning, but not during sparse scanning, BOLD signals were significantly stronger for joy than for neutral in the left auditory cortex and for joy than for fear in the calcarine sulcus. To the authors' knowledge, this is the first study to show a statistical interaction effect between scanner noise and affective processes and extends evidence suggesting scanner noise to be an important factor in functional MRI research that can affect and distort affective brain processes.本研究旨在探讨功能磁共振成像（functional MRI）扫描仪噪声与情感神经加工过程之间的交互效应。实验刺激包含经心理声学平衡处理的乐曲片段，可表达三种不同情绪：恐惧、中性与愉悦。本研究共招募34名参与者（其中女性19名），将其分为两组：一组接受连续扫描模式，另一组采用扫描噪声更低的稀疏时间扫描模式。随后，研究团队对扫描组别（稀疏/低噪声组 vs 连续/高噪声组）与情绪类型（恐惧、中性、愉悦）之间的交互效应开展了检验。研究结果显示，刺激的情绪表达与扫描组别之间的交互效应定位于双侧听觉皮层、岛叶以及视觉皮层（距状沟）。事后比较分析显示，在稀疏扫描而非连续扫描条件下，双侧听觉皮层内的血氧水平依赖（Blood Oxygen Level Dependent, BOLD）信号在愉悦条件下显著强于恐惧条件，且恐惧条件下的信号显著强于中性条件；而在连续扫描而非稀疏扫描条件下，左侧听觉皮层内愉悦条件下的BOLD信号显著强于中性条件，距状沟内愉悦条件下的信号显著强于恐惧条件。据作者所知，本研究首次揭示了扫描仪噪声与情感加工过程之间的统计学交互效应，补充了相关研究证据，表明扫描仪噪声是功能磁共振成像研究中的重要影响因素，可对情感相关的大脑加工过程造成干扰甚至扭曲。