Mental Health Service, San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA 94121, USA.
Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
Schizophr Bull. 2023 Sep 7;49(5):1364-1374. doi: 10.1093/schbul/sbad014.
Functional magnetic resonance imaging (fMRI) scanners are unavoidably loud and uncomfortable experimental tools that are necessary for schizophrenia (SZ) neuroscience research. The validity of fMRI paradigms might be undermined by well-known sensory processing abnormalities in SZ that could exert distinct effects on neural activity in the presence of scanner background sound. Given the ubiquity of resting-state fMRI (rs-fMRI) paradigms in SZ research, elucidating the relationship between neural, hemodynamic, and sensory processing deficits during scanning is necessary to refine the construct validity of the MR neuroimaging environment. We recorded simultaneous electroencephalography (EEG)-fMRI at rest in people with SZ (n = 57) and healthy control participants without a psychiatric diagnosis (n = 46) and identified gamma EEG activity in the same frequency range as the background sounds emitted from our scanner during a resting-state sequence. In participants with SZ, gamma coupling to the hemodynamic signal was reduced in bilateral auditory regions of the superior temporal gyri. Impaired gamma-hemodynamic coupling was associated with sensory gating deficits and worse symptom severity. Fundamental sensory-neural processing deficits in SZ are present at rest when considering scanner background sound as a "stimulus." This finding may impact the interpretation of rs-fMRI activity in studies of people with SZ. Future neuroimaging research in SZ might consider background sound as a confounding variable, potentially related to fluctuations in neural excitability and arousal.
功能磁共振成像（fMRI）扫描仪不可避免地会产生噪音且令人不适，它们是精神分裂症（SZ）神经科学研究所必需的实验工具。由于 SZ 存在众所周知的感觉处理异常，这些异常可能会对神经活动产生明显影响，而 fMRI 范式的有效性可能会因此受到影响。鉴于静息态 fMRI（rs-fMRI）范式在 SZ 研究中的广泛应用，阐明扫描期间神经、血液动力学和感觉处理缺陷之间的关系对于完善磁共振神经影像学环境的构建效度是必要的。我们在有 SZ 的参与者（n = 57）和没有精神科诊断的健康对照组参与者（n = 46）中同时记录了静息状态下的脑电图（EEG）-fMRI，并在 rs 序列期间识别出与我们扫描仪发出的背景声音相同频率范围内的伽马 EEG 活动。在 SZ 参与者中，双侧颞上回的听觉区域的伽马耦合到血液动力学信号减少。伽马-血液动力学耦合受损与感觉门控缺陷和更严重的症状严重程度相关。当考虑扫描仪背景声音作为“刺激”时，SZ 中存在基本的感觉-神经处理缺陷。这一发现可能会影响对 SZ 患者 rs-fMRI 活动的解释。未来的 SZ 神经影像学研究可能会将背景声音视为混杂变量，这可能与神经兴奋性和唤醒的波动有关。
