Abstract：
Gamma oscillations play a functional role in brain cognitions. Recently, auditory steady-state response (ASSR) has been reported abnormally in depression clinically, particularly in the low-gamma band. However, clinical electroencephalography research has challenges obtaining pure signals straight from the source level, making information isolation and precise localization difficult. Besides, the ASSR deficits pattern remains unclear. Herein, we focused on the origin of ASSR-primary auditory cortex (A1), the central node in the auditory pathway. We assessed the evoked-power and phase-synchronization using local field potentials (LFP) in depression (n = 21) and control (n = 22) rats. Subsequent processing of the received auditory information was examined using event-related potentials (AEPs). Results showed that depressed rats exhibited significant gamma ASSR impairments in peak-to-peak amplitude, inter-trial phase coherence, and signal-to-noise ratio. These deficits were more pronounced during 40-Hz auditory stimuli in right-A1, indicating severe gamma network abnormalities in the right auditory pathway. Besides, increased N2 and P3 amplitudes in depression group were found, indicating excessive inhibitory control and contextual processing. Taken together, these ASSR abnormalities have a high specificity of more than 90% and high sensitivity of more than 80% to distinguish depression under 40-Hz auditory stimuli. Our findings provided an abnormal gamma network in the auditory pathway, as a promising diagnostic biomarker in the future.
摘要：
伽玛振荡在大脑认知中起着功能性作用。最近,听觉稳态反应（ASSR）在抑郁症临床上有异常报道，特别是在低伽马波段。然而,临床脑电图研究面临挑战，直接从源头水平获得纯信号，使信息隔离和精确定位变得困难。此外,ASSR赤字模式尚不清楚。在这里，我们专注于ASSR-初级听觉皮层（A1）的起源，听觉通路的中央节点.我们使用局部场电位（LFP）评估了抑郁症（n=21）和对照（n=22）大鼠的诱发功率和相位同步。使用事件相关电位（AEP）检查接收到的听觉信息的后续处理。结果显示，抑郁大鼠在峰到峰幅度上表现出明显的γASSR损伤，试验间阶段一致性，和信噪比。在右A1的40Hz听觉刺激中，这些缺陷更为明显，表明右听觉通路中存在严重的伽马网络异常。此外,抑郁症组N2和P3振幅增加，表明过度的抑制控制和上下文处理。一起来看,这些ASSR异常对40Hz听觉刺激下的抑郁症具有90%以上的高特异性和80%以上的高灵敏度。我们的发现在听觉通路中提供了一个异常的伽马网络，作为未来有前途的诊断生物标志物。
