Figure 2.

Eyeblink conditioning in an individual subject during anodal tDCS using the cephalic reference electrode. Rectified and filtered EMG-data of the orbicularis oculi muscle are shown from the beginning with the unpaired phase (top) consisting of 16 CS alone and 16 US alone trials in a random sequence followed by 100 CS-US paired trials and 30 CS alone extinction trials at the end of the experiment (bottom). tDCS was started with the second half of unpaired and lasted throughout the first half of paired trials. The vertical lines indicate the onset of the CS and US. Responses occurring within the 150 ms interval after CS onset (dotted line) were considered alpha-responses. See “Subjects and Methods” Section for further details.