Mental Illness Research, Education and Clinical Center (MIRECC), VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA.
Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA.
Clin EEG Neurosci. 2020 Nov;51(6):382-389. doi: 10.1177/1550059420925697. Epub 2020 May 28.
People with schizophrenia (SZ) exhibit visual processing abnormalities that affect their daily functioning and remediating these deficits might help to improve functioning. Transcranial direct current stimulation (tDCS) is a potential tool for perceptual enhancement for this purpose, though there are no reports of tDCS applied to visual cortex in SZ. In a within-subject, crossover design, we evaluated the effects of tDCS on visual processing in 27 SZ. All patients received anodal, cathodal, or sham stimulation over the central occipital region in 3 visits separated by 1 week. In each visit, a backward masking task and an electroencephalography measure of visual neuroplasticity were administered after tDCS. Neuroplasticity was assessed with visual evoked potentials before and after tetanizing visual high-frequency stimulation. Masking performance was significantly poorer in the anodal and cathodal conditions compared with sham. Both anodal and cathodal stimulation increased the amplitude of P1 but did not change the plasticity index. We found significant plasticity effects of tDCS for only one waveform for one stimulation condition (P2 for anodal tDCS) which did not survive correction for multiple comparisons. The reason for the lack of tDCS stimulation effects on plasticity may be because tDCS was not delivered simultaneously with the tetanizing visual stimulus. The present findings emphasize the need for more research on the relevant parameters for stimulation of visual processing regions in clinical populations.
精神分裂症患者（SZ）表现出视觉处理异常，这影响了他们的日常功能，而纠正这些缺陷可能有助于改善他们的功能。经颅直流电刺激（tDCS）是一种用于增强感知的潜在工具，但目前尚无关于 tDCS 应用于 SZ 视觉皮层的报道。在一项单盲、交叉设计中，我们评估了 tDCS 对 27 名 SZ 患者视觉处理的影响。所有患者在 3 次就诊中分别接受了中央枕区的阳极、阴极或假刺激，每次就诊间隔 1 周。在每次就诊中，tDCS 后进行了反向掩蔽任务和视觉神经可塑性的脑电图测量。在进行视觉高频刺激的强直刺激前后，通过视觉诱发电位评估神经可塑性。与假刺激相比，阳极和阴极刺激条件下的掩蔽性能明显更差。阳极和阴极刺激均增加了 P1 的振幅，但并未改变可塑性指数。我们仅发现 tDCS 对一种刺激条件下的一种波形具有显著的可塑性效应（阳极 tDCS 的 P2），但在进行多次比较校正后，该效应不再显著。tDCS 对可塑性没有刺激作用的原因可能是因为 tDCS 没有与强直视觉刺激同时进行。本研究结果强调需要对临床人群中视觉处理区域的刺激相关参数进行更多研究。
