Department of Psychology, University of California, Los Angeles, Los Angeles, CA 90095-1563, USA.
Neuropsychologia. 2013 Jun;51(7):1234-9. doi: 10.1016/j.neuropsychologia.2013.03.013. Epub 2013 Apr 2.
This study examined the effects of visual cortex transcranial direct current stimulation (tDCS) on visual processing and learning. Participants performed a contrast detection task on two consecutive days. Each session consisted of a baseline measurement followed by measurements made during active or sham stimulation. On the first day, one group received anodal stimulation to primary visual cortex (V1), while another received cathodal stimulation. Stimulation polarity was reversed for these groups on the second day. The third (control) group of subjects received sham stimulation on both days. No improvements or decrements in contrast sensitivity relative to the same-day baseline were observed during real tDCS, nor was any within-session learning trend observed. However, task performance improved significantly from Day 1 to Day 2 for the participants who received cathodal tDCS on Day 1 and for the sham group. No such improvement was found for the participants who received anodal stimulation on Day 1, indicating that anodal tDCS blocked overnight consolidation of visual learning, perhaps through engagement of inhibitory homeostatic plasticity mechanisms or alteration of the signal-to-noise ratio within stimulated cortex. These results show that applying tDCS to the visual cortex can modify consolidation of visual learning.
本研究考察了视觉皮层经颅直流电刺激（tDCS）对视觉处理和学习的影响。参与者在连续两天进行对比检测任务。每个会话都包括基线测量，然后在主动或假刺激期间进行测量。第一天，一组接受初级视觉皮层（V1）的阳极刺激，另一组接受阴极刺激。第二天，这些组的刺激极性被反转。第三组（对照组）的受试者在两天内都接受假刺激。在真正的 tDCS 期间，相对于同一天的基线，对比敏感度没有提高或降低，也没有观察到任何会话内的学习趋势。然而，对于第一天接受阴极 tDCS 的参与者和假刺激组，任务表现从第一天到第二天显著提高。对于第一天接受阳极刺激的参与者，没有发现这种提高，这表明阳极 tDCS 阻断了视觉学习的夜间巩固，可能是通过参与抑制性同型可塑性机制或改变刺激皮层内的信号噪声比。这些结果表明，将 tDCS 应用于视觉皮层可以改变视觉学习的巩固。
