Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, Department of Psychiatry, Harvard Medical School, Boston, MA, USA; Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Japan; National Hospital Organization, Hizen Psychiatric Center, Japan.
Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, Department of Psychiatry, Harvard Medical School, Boston, MA, USA; Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Japan.
Schizophr Res. 2019 Jun;208:145-152. doi: 10.1016/j.schres.2019.03.025. Epub 2019 Apr 17.
The early auditory-evoked gamma band response (EAGBR) may serve as an index of the integrity of fast recurrent inhibition or synaptic connectivity in the auditory cortex, where abnormalities in individuals with schizophrenia have been consistently found. The EAGBR has been rarely investigated in first episode schizophrenia patients (FESZ) and individuals at clinical high risk (CHR) for schizophrenia, and never been compared directly between these populations nor evaluated longitudinally. Here we examined the EAGBR in FESZ, CHR, and matched healthy controls (HC) at baseline and 1-year follow-up assessments to determine whether the EAGBR was affected in these clinical groups, and whether any EAGBR abnormalities changed over time. The electroencephalogram was recorded with a dense electrode array while subjects (18 FESZ, 18 CHR, and 40 HC) performed an auditory oddball task. Event-related spectral measures (phase locking factor [PLF] and evoked power) were computed on Morlet-wavelet-transformed single epochs from the standard trials. At baseline, EAGBR PLF and evoked power did not differ between groups. FESZ showed progressive reductions of PLF and evoked power from baseline to follow-up, and deficits in PLF at follow-up compared to HC. EAGBR peak frequency also increased at temporal sites in FESZ from baseline to follow-up. Longitudinal effects on the EAGBR were not found in CHR or HC, nor did these groups differ at follow-up. In conclusion, we detected neurophysiological changes of auditory cortex function in FESZ during a one-year period, which were not observed in CHR. These findings are discussed within the context of neurodevelopmental models of schizophrenia.
早期听觉诱发伽马带反应（EAGBR）可作为听觉皮层中快速重复抑制或突触连接完整性的指标，在精神分裂症患者中一直存在异常。EAGBR 在首发精神分裂症患者（FESZ）和精神分裂症临床高危个体（CHR）中很少被研究，并且从未在这些人群中直接比较过，也没有进行纵向评估。在这里，我们在基线和 1 年随访评估时检查了 FESZ、CHR 和匹配的健康对照者（HC）的 EAGBR，以确定 EAGBR 是否在这些临床人群中受到影响，以及任何 EAGBR 异常是否随时间而变化。当受试者（18 名 FESZ、18 名 CHR 和 40 名 HC）执行听觉Oddball 任务时，使用密集电极阵列记录脑电图。在标准试验的 Morlet 小波变换单个时段上计算事件相关频谱测量值（锁相因子[PLF]和诱发功率）。在基线时，EAGBR 的 PLF 和诱发功率在组间无差异。FESZ 从基线到随访显示 PLF 和诱发功率逐渐降低，并且在随访时与 HC 相比，PLF 出现缺陷。EAGBR 峰值频率也在 FESZ 从基线到随访的时间部位增加。在 CHR 或 HC 中未发现 EAGBR 的纵向影响，并且在随访时这些组也没有差异。总之，我们在 FESZ 中检测到听觉皮层功能的神经生理变化，在 CHR 中未观察到。这些发现在精神分裂症的神经发育模型背景下进行了讨论。
