Electrophysiological correlates of the drift diffusion model in visual word recognition.

This study was designed to explore the electrophysiological correlates of the diffusion models drift rate parameter in cognitive decision making. Eighty-two participants completed a lexical decision task while their stimulus-dependent event-related potentials (ERP) and theta frequency band power were measured. A mass univariate approach was applied to examine the timeline at which correlations were evident. Individual differences in drift rate parameter and condition-wise within-subject differences in drift rates for word emotionality and item repetition were found to be related to amplitude differences in the late positive complex (LPC). No relations to theta frequency band power changes were obtained. The drift rate parameter captures information accumulation of noisy evidence, while LPC amplitudes are discussed to reflect the strength of a memory trace. While these results point to a common underlying cognitive mechanism to explain drift rates and LPC modulation, they also provide a new angle on the timeline of visual word processing following word identification. Further confirmations of the results are needed to approve the LPC as neurophysiological marker of information accumulation. Hum Brain Mapp 38:5616-5627, 2017.