Hamm Jordan P, Bobilev Anastasia M, Hayrynen Lauren K, Hudgens-Haney Matthew E, Oliver William T, Parker David A, McDowell Jennifer E, Buckley Peter A, Clementz Brett A
Department of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA, United States.
Department of Psychiatry, Georgia Reagents University, Medical College of Georgia, Augusta, GA, United States.
Schizophr Res. 2015 Jun;165(1):97-102. doi: 10.1016/j.schres.2015.02.016. Epub 2015 Apr 11.
Electroencephalographic (EEG) studies of auditory steady-state responses (aSSRs) non-invasively probe gamma-band (40-Hz) oscillatory capacity in sensory cortex with high signal-to-noise ratio. Consistent reports of reduced 40-Hz aSSRs in persons with schizophrenia (SZ) indicate its potential as an efficient biomarker for the disease, but studies have been limited to passive or indirect listening contexts with stereotypically short (500ms) stimulus trains. An inability to modulate sensorineural processing in accord with behavioral goals or within the sensory environmental context may represent a fundamental deficit in SZ, but whether and how this deficit relates to reduced aSSRs is unknown. We systematically varied stimulus duration and attentional contexts to further mature the 40-Hz aSSR as biomarker for future translational or mechanistic studies. Eighteen SZ and 18 healthy subjects (H) were presented binaural pure-tones with or without sinusoidal amplitude modulation at 40-Hz. Stimulus duration (500-ms or 1500-ms) and attention (via a button press task) were varied across 4 separate blocks. Evoked potentials recorded with dense-array EEGs were analyzed in the time-frequency domain. SZ displayed reduced 40-Hz aSSRs to typical stimulation parameters, replicating previous findings. In H, aSSRs were reduced when stimuli were presented in longer trains and were slightly enhanced by attention. Only the former modulation was impaired in SZ and correlated with sensory discrimination performance. Thus, gamma-band aSSRs are modulated by both attentional and stimulus duration contexts, but only modulations related to physical stimulus properties are abnormal in SZ, supporting its status as a biomarker of psychotic perceptual disturbance involving non-attentional sensori-cortical circuits.
脑电图（EEG）对听觉稳态反应（aSSR）的研究以高信噪比非侵入性地探测感觉皮层中的伽马波段（40赫兹）振荡能力。对精神分裂症（SZ）患者40赫兹aSSR降低的一致报告表明其有潜力成为该疾病的有效生物标志物，但研究仅限于被动或间接聆听情境，且刺激序列通常较短（500毫秒）。无法根据行为目标或在感觉环境背景下调节感觉神经处理可能代表SZ的一种基本缺陷，但这种缺陷是否以及如何与aSSR降低相关尚不清楚。我们系统地改变刺激持续时间和注意力情境，以进一步完善40赫兹aSSR作为未来转化或机制研究的生物标志物。向18名SZ患者和18名健康受试者（H）双耳呈现40赫兹有或无正弦幅度调制的纯音。刺激持续时间（500毫秒或1500毫秒）和注意力（通过按键任务）在4个独立的组块中变化。用密集阵列脑电图记录的诱发电位在时频域进行分析。SZ患者对典型刺激参数的40赫兹aSSR降低，重复了先前的研究结果。在H组中，当刺激序列较长时aSSR降低，注意力可使其略有增强。在SZ患者中，只有前一种调制受损，且与感觉辨别性能相关。因此，伽马波段aSSR受注意力和刺激持续时间情境的调节，但在SZ患者中只有与物理刺激特性相关的调制异常，这支持了其作为涉及非注意力感觉皮层回路的精神病性感知障碍生物标志物的地位。
