Experiment 1, frontotemporal HD-tACS procedure and task.a, The multifocal inphase frontotemporal HD-tACS montage and current-flow model shown on 3D reconstructions of the cortical surface. The location and current intensity value of each stimulating electrode are shown. The left prefrontal cortex and left temporal cortex were targeted, each with three electrodes in a center-surround, source-sink pattern to achieve maximum focality. b, All trials began with fixation followed by a target and then a delay period. In memory blocks, subjects judged whether a later probe was the same or a modified version of the target. In control blocks, subjects judged whether a backward masked grating probe was tilted clockwise or counterclockwise from the vertical and were not required to remember the target. Trial-by-trial adjustments in orientation magnitude of the probe ensured comparable performance across memory and control blocks.
