2.1 Participants
Thirty-seven participants with normal or corrected-to-normal vision were
recruited for the experiment. Participants who had neuronal disease or a
family history of epilepsy were excluded. Among the recruited
participants, eleven did not finish the task because they could not
detect phosphene with the maximum intensity (2000 μA) in any of the
stimulation conditions. During data analysis, data from one participant
was excluded because they responded earlier than stimulation had begun.
As a result, data from 25 participants (13 males aged 20 – 45) were
included in the analysis. All participants were instructed on the
experimental procedures and provided their signed consent on a form that
received approval from the Institutional Review Board of Chang-Gung
Memorial Hospital, Taiwan.