Abstract
We detail the use of several off-the-shelf hardware and software components to create an inexpensive “homemade” ERP device. We used this machine to try to find the N170 to faces relative to other object classes and to faces relative to inverted faces. We took hardware bandpass filtered (1-100 Hz) analog outputs of a common polygraph (Grass Instruments model 79D; used models were available at the time of abstract submission for well under $700) which normally provides output to pens, and instead sent the signal through a National Instruments USB data acquisition card. MATLAB was used to present stimuli and to analyze signal output. We have thus far used single electrodes placed via the 10-10 system and with regard to published coordinates. Electrodes were placed over the left and right FFA and we used the ear as reference. Despite the paucity of electrodes, initial results are promising and show strong negative deflections to faces in the range of 100-200 ms post-stimulus. The goal of our poster presentation is to present our hardware and software methods in detail to the vision community and to gather feedback that might be helpful to us and to other small colleges with minimal cognitive neuroscientific equipment budgets.