Code for: It’s more than Interference: Examining the Neuro-Hemodynamic Correlates of the Flanker Task with functional Near-Infrared Spectroscopy

This contains code for ePrime 2.0.10.252. The code is used to generate die Flanker experiment; code for NIRS Brain AnalyzIR Toolbox v0.1 for Matlab2014b or higher; Syntax for SPSS 25 for the analysis of Behavioral Data Flanker Task. Previous functional near‐infrared spectroscopy studies using the Eriksen flanker task, in contrast to functional magnetic resonance imaging studies, revealed the quite puzzling finding of an inverted conflict effect, that is, greater middle and superior frontal activation in response compatible than in response incompatible trials. However, since neither prior functional near‐infrared spectroscopy studies nor most previous functional magnetic resonance imaging studies separated between an identical and a compatible condition, it is hard to pinpoint whether this discrepancy occurs on the level of stimulus processing or response generation. By assigning two letters to both left (D, F) and right (J, K) hand reactions, we were able to separate identical (e.g., JJJ) and compatible (e.g., JKJ) conditions that solely differ in their stimulus congruency. Replicating prior functional magnetic resonance imaging findings, we found the standard conflict effect at the transition of superior and middle frontal gyrus, when comparing the activation in compatible trials to that in incompatible trials. Both changes in oxygenated and deoxygenated hemoglobin thus pointed to more effortful processing in incompatible trials. Interestingly, however, identical trials showed the highest activation in this region, according to both changes in oxygenated and deoxygenated blood. A finding that mirrors and extends prior functional near‐infrared spectroscopy findings, which only regarded oxygenated blood. We argue that this pattern of results does not reflect the standard conflict effect. We rather assume that other processes like perceptual familiarity or strategic readjustment might be at play. Code for: Geissler (Geißler), C. F., Hofmann, M. J., & Frings, C. (2020). It is more than Interference: Examining the neurohemodynamic correlates of the flanker task with functional near‐infrared spectroscopy. European Journal of Neuroscience, 52(3), 3022–3031. https://doi.org/10.1111/ejn.14708 The Rhineland‐Palatinate (Rheinland‐Pfalz) research group Psychobiology of Stress (2017, 2018) funded this study. ePrime Code for Flanker-Task; NIRS Toolbox Processing Pipeline for Neuro Data of Flanker Task; SPSS Syntax for Behavioral Data