Measurement, time-stamping and analysis of electrodermal activity in fMRI

Christopher Smyser, Thomas Grabowski, Pierre Rainville, Antoine Bechara, Mehrdad Razavi, Sonya Mehta, Brent Eaton, Lizann Bolinger

Research output: Contribution to journalArticlepeer-review


A low cost fMRI-compatible system was developed for detecting electrodermal activity without inducing image artifact. Subject electrodermal activity was measured on the plantar surface of the foot using a standard recording circuit. Filtered analog skin conductance responses (SCR) were recorded with a general purpose, time-stamping data acquisition system. A conditioning paradigm involving painful thermal stimulation was used to demonstrate SCR detection and investigate neural correlates of conditioned autonomic activity. 128x128 pixel EPI-BOLD images were acquired with a GE 1.5T Signa scanner. Image analysis was performed using voxel-wise multiple linear regression. The covariate of interest was generated by convolving stimulus event onset with a standard hemodynamic response function. The function was time-shifted to determine optimal activation. Significance was tested using the t-statistic. Image quality was unaffected by the device, and conditioned and unconditioned SCRs were successfully detected. Conditioned SCRs correlated significantly with activity in the right anterior insular cortex. The effect was more robust when responses were scaled by SCR amplitude. The ability to measure and time register SCRs during fMRI acquisition enables studies of cognitive processes marked by autonomic activity, including those involving decision-making, pain, emotion, and addiction.

Original languageEnglish
Pages (from-to)470-475
Number of pages6
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jan 1 2002


  • Autonomic nervous system
  • Brain
  • Conditioning
  • Data acquisition
  • Electrodermal activity
  • Fmri
  • Linear models


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