Fig. 1

At the start of each trial, a triangle indicated the required SCP polarity: upward for negative shifts (increased cortical activation), downward for positive shifts (decreased cortical activation / inhibition). Following baseline recording, SCP activity was displayed in real time as a moving object (e.g., a fish or moon) on the participant’s screen, with upward movement reflecting increased and downward movement decreased cortical activation. Participants were instructed to volitionally control the object’s movement by producing SCP shifts in the indicated direction. Successful regulation—defined as a shift in the required polarity lasting at least 2 consecutive seconds within the final 4 s of a trial—was rewarded with a sun symbol and verbal encouragement from the trainers. Each session began with an eye movement calibration task to enable real-time artifact correction and minimize eye movement influences