April 25
Behavior-contingent analysis of fixation-related brain potentials: Past findings and new tools for co-registration research
Elizabeth Schotter
Department of Psychology, University of South Florida
Recent years have seen a rise in excitement around co-registration (i.e., synchronized measurement of eye tracking, ET and electroencephalography, EEG), which allows researchers to investigate eye fixation-related brain potentials (FRPs). One major focus of co-registration research has been on the reading process – a naturalistic task that involves the interface of many cognitive, perceptual, and motor systems, allowing it to be a testbed for many questions within cognitive neuroscience. But future progress hinges upon researchers synchronizing not only data streams, but also approaches to analyzing the data in a way that capitalizes on the technique’s strength — the ability to directly link neural processing to eye movement behaviors. To make the most of this technique, we must move away from univariate analysis (i.e., treating ET and EEG data as independent outcomes) and toward approaches that account for the multivariate coupling between neural processing and behavioral actions. As an example, I will summarize a few co-registration studies that use behavior-contingent analysis (BCA) to reveal how language-related brain processes (e.g., N400, LPC) are only observed when the reader exhibits specific behaviors (e.g., skipping, regressions). Furthermore, in order to facilitate adoption of these integrated approaches to co-registration research, I will provide an overview of a MATLAB toolbox my lab has developed (i.e., EyeSort) that will allow co-registration researchers to identify certain eye movement behaviors and mark them in the EEG event structure in a way that is flexible and customizable.