Measuring Event-Related Electrodermal Activity

We recorded human participants’ electrodermal activity (EDA), a measurement of skin conductance in microsiemens (μS), whilst they performed the DMS. To measure the event-related changes in EDA in real-time, the electrodermal recording unit software (ML116 GSR Amp, ADInstruments) was employed at a sampling rate of 75 kHz^{47 (link),48 (link)}. Two electrodes were attached to the index and ring fingers of the participants’ non-dominant hand to measure skin conductance. Since the electrodes are sensitive to movement-related noise, participants were advised to keep their hand still. We calculated the difference between the minimum and maximum amplitudes of the phasic activity for each event-related electrodermal signal within a 3 s time epoch following target selection^{47 (link),49} . However, due to various factors that included motion artefacts, cold hands, and low sweating levels, EDA readings were not adequately recorded for three participants. Two observers blinded to the data analyses assessed the quality of recorded EDA for exclusion of unreliable data. Therefore, EDA data obtained from 31 participants were used in EDA data analysis.