Objective: (1) To investigate the hypothesis that the vertex positive potential (VPP) and the N170 ERP components reported in the face processing literature are two manifestations of the samebrain processes whose relative amplitude in a given experiment is dependent on referenceelectrode; (2) to investigate whether differences in face/object results reported in studies looking at the VPP and N170 are attributable to the location of reference.

Methods: EEG was recorded from 53 scalp electrodes referenced online to the left mastoid while subjects viewed face, car and word stimuli. Off-line, the data were systematically re-referenced to the common average, averaged mastoids, averaged earlobes, non-cephalic, and nose. The correlation of timing, amplitude, and effects was investigated across referenceelectrodes.

Results: (1) The amplitude of the N170 and VPPcomponents varies in a precisely inverse manner across reference; (2) the peaks of the N170 and VPP are temporally coincident for all referenceelectrodes, (3) both components can be accounted for by the same dipolar configuration, and (4) the components show identical functional properties.

Conclusions: The VPP and N170 are two ‘faces’ of the samebrain generators.

Significance: The differential N170/VPPeffects observed in ERP studies can be accounted for by differences in reference methodology.