Departments of Psychology and Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA 30602, United States.
Schizophr Res. 2011 Dec;133(1-3):106-11. doi: 10.1016/j.schres.2011.07.016. Epub 2011 Aug 11.
Schizophrenia patients (SZ) show early visual processing deficits in many, but not all, tasks. These deficits may be associated with dysregulation of intrinsic oscillatory activity that compromises signal-to-noise in the SZ brain. This question was studied using visual steady-state stimulation and post-steady-state presentation of transient visual stimuli. SZ had higher intrinsic oscillatory activity at the steady-state stimulation frequency (12.5 Hz) and at the 6.25 Hz subharmonic, showed a significant decrease in visual steady-state magnitude over 2s of stimulation, and were unable to promptly terminate the steady-state response following stimulation offset. If adjustment for levels of intrinsic brain activity were made, however, it would have appeared that SZ had activity of similar magnitude as healthy subjects following steady-state stimulus termination, indicating that such adjustments could substantially alter theoretical interpretations. Visual evoked potential abnormalities (N1/P2 amplitudes) present among SZ at the initiation of steady-state stimulation were less apparent in the 750 ms immediately following steady-state stimulation offset. Higher intrinsic oscillatory brain activity may be a fundamental characteristic of SZ that merits further evaluation for understanding this disorder's neuropathological correlates and associated symptomatology.
精神分裂症患者（SZ）在许多但不是所有任务中都表现出早期视觉处理缺陷。这些缺陷可能与内在振荡活动的失调有关，这种失调会影响 SZ 大脑中的信号噪声比。本研究使用视觉稳态刺激和瞬态视觉刺激的稳态后呈现来研究这个问题。SZ 在稳态刺激频率（12.5 Hz）和 6.25 Hz 次谐波处具有更高的内在振荡活动，在 2 秒的刺激过程中视觉稳态幅度显著下降，并且在刺激结束后无法迅速终止稳态响应。然而，如果对内在大脑活动水平进行调整，那么 SZ 在稳态刺激结束后的活动似乎与健康受试者的活动相似，表明这种调整可能会极大地改变理论解释。在稳态刺激开始时，SZ 存在的视觉诱发电位异常（N1/P2 幅度）在稳态刺激结束后 750 毫秒内不太明显。更高的内在振荡大脑活动可能是 SZ 的一个基本特征，值得进一步评估，以了解这种障碍的神经病理学相关性和相关症状。
