Nakanishi Shoichiro, Tamura Shunsuke, Hirano Shogo, Takahashi Junichi, Kitajima Kazutoshi, Takai Yoshifumi, Mitsudo Takako, Togao Osamu, Nakao Tomohiro, Onitsuka Toshiaki, Hirano Yoji
Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Department of Psychiatry, Division of Clinical Neuroscience, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
Front Neurosci. 2023 Oct 24;17:1277733. doi: 10.3389/fnins.2023.1277733. eCollection 2023.
Gamma-band oscillatory deficits have attracted considerable attention as promising biomarkers of schizophrenia (SZ). Notably, a reduced auditory steady-state response (ASSR) in the low gamma band (40 Hz) is widely recognized as a robust finding among SZ patients. However, a comprehensive investigation into the potential utility of the high-gamma-band ASSR in detecting altered neural oscillations in SZ has not yet been conducted.
The present study aimed to assess the ASSR using magnetoencephalography (MEG) data obtained during steady-state stimuli at frequencies of 20, 30, 40, and 80 Hz from 23 SZ patients and 21 healthy controls (HCs). To evaluate the ASSR, we examined the evoked power and phase-locking factor (PLF) in the time-frequency domain for both the primary and secondary auditory cortices. Furthermore, we calculated the phase-locking angle (PLA) to examine oscillatory phase lead or delay in SZ patients. Taking advantage of the high spatial resolution of MEG, we also focused on the hemispheric laterality of low- and high-gamma-band ASSR deficits in SZ.
We found abnormal phase delay in the 40 Hz ASSR within the bilateral auditory cortex of SZ patients. Regarding the 80 Hz ASSR, our investigation identified an aberrant phase lead in the left secondary auditory cortex in SZ, accompanied by reduced evoked power in both auditory cortices.
Given that abnormal phase lead on 80 Hz ASSR exhibited the highest discriminative power between HC and SZ, we propose that the examination of PLA in the 80 Hz ASSR holds significant promise as a robust candidate for identifying neurophysiological endophenotypes associated with SZ. Furthermore, the left-hemisphere phase lead observed in the deficits of 80 Hz PLA aligns with numerous prior studies, which have consistently proposed that SZ is characterized by left-lateralized brain dysfunctions.
伽马波段振荡缺陷作为精神分裂症（SZ）有前景的生物标志物已引起广泛关注。值得注意的是，低伽马波段（40赫兹）听觉稳态反应（ASSR）降低在SZ患者中是一项广泛认可的可靠发现。然而，尚未对高伽马波段ASSR在检测SZ患者神经振荡改变方面的潜在效用进行全面研究。
本研究旨在利用23名SZ患者和21名健康对照（HC）在20、30、40和80赫兹稳态刺激期间获得的脑磁图（MEG）数据评估ASSR。为评估ASSR，我们在时频域检查了初级和次级听觉皮层的诱发功率和锁相因子（PLF）。此外，我们计算了锁相角（PLA）以检查SZ患者的振荡相位超前或延迟。利用MEG的高空间分辨率，我们还关注了SZ患者低伽马波段和高伽马波段ASSR缺陷的半球偏侧性。
我们发现SZ患者双侧听觉皮层内40赫兹ASSR存在异常相位延迟。关于80赫兹ASSR，我们的研究发现SZ患者左次级听觉皮层存在异常相位超前，同时两个听觉皮层的诱发功率均降低。
鉴于80赫兹ASSR上的异常相位超前在HC和SZ之间表现出最高的鉴别力，我们提出检查80赫兹ASSR中的PLA作为识别与SZ相关的神经生理内表型的有力候选具有重要前景。此外，在80赫兹PLA缺陷中观察到的左半球相位超前与众多先前研究一致，这些研究一直认为SZ的特征是左侧大脑功能障碍。
