Experimental setup for the perception threshold measurement. The experimental procedure was executed on a computerized platform. The stimulation profiles were configured through the stimulation control software residing in ' Computer 1 '. The STG2008 generated analog voltage output, and then the DS5s translated the voltage signal into current signal. The stimuli were delivered to one or two electrodes selected by the 'Switches'. The subject answered whether or not they perceived a stimulus through a Graphical User Interface displayed in 'Computer 2'.