title: Individual differences in the Simon effect are underpinned by differences in the competitive dynamics in the basal ganglia: An experimental verification and a computational model.
abstract: Cognitive control is thought to be made possible by the activity of the prefrontal cortex, which selectively uses task-specific representations to bias the selection of task-appropriate responses over more automated, but inappropriate, ones. Recent models have suggested, however, that prefrontal representations are in turn controlled by the basal ganglia. In particular, neurophysiological considerations suggest that the basal ganglia's indirect pathway plays a pivotal role in preventing irrelevant information from being incorporated into a task, thus reducing response interference due to the processing of inappropriate stimuli dimensions. Here, we test this hypothesis by showing that individual differences in a non-verbal cognitive control task (the Simon task) are correlated with performance on a decision-making task (the Probabilistic Stimulus Selection task) that tracks the contribution of the indirect pathway. Specifically, the higher the effect of the indirect pathway, the smaller was the behavioral costs associated with suppressing interference in incongruent trials. Additionally, it was found that this correlation was driven by individual differences in incongruent trials only (with little effect on congruent ones) and specific to the indirect pathway (with almost no correlation with the effect of the direct pathways). Finally, it is shown that this pattern of results is precisely what is predicted when competitive dynamics of the basal ganglia are added to the selective attention component of a simple model of the Simon task, thus showing that our experimental results can be fully explained by our initial hypothesis.
authors.affiliation: Department of Psychology, University of Washington, Seattle, WA 98195, United States; Institute for Learning and Brain Sciences (I-LABS), University of Washington, Seattle, WA 98195, United States; Center for Sensorimotor Neural Engineering, University of Washington, Seattle, WA 98195, United States; University of Washington Institute of Neuroengineering (UWIN), Seattle, WA 98195, United States. Electronic address: stocco@uw.edu.
authors.forename: Andrea
authors.initials: A
authors.lastname: Stocco
authors.affiliation: Institute for Learning and Brain Sciences (I-LABS), University of Washington, Seattle, WA 98195, United States. Electronic address: nlmurray44@hotmail.com.
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Murray
authors.affiliation: Department of Psychology, University of Washington, Seattle, WA 98195, United States; Institute for Learning and Brain Sciences (I-LABS), University of Washington, Seattle, WA 98195, United States. Electronic address: bly4@uw.edu.
authors.forename: Brianna L
authors.initials: BL
authors.lastname: Yamasaki
authors.affiliation: Department of Psychology, University of Washington, Seattle, WA 98195, United States. Electronic address: tayoren@uw.edu.
authors.forename: Taylor J
authors.initials: TJ
authors.lastname: Renno
authors.affiliation: Department of Psychology, University of Washington, Seattle, WA 98195, United States. Electronic address: jimmynguyen431@gmail.com.
authors.forename: Jimmy
authors.initials: J
authors.lastname: Nguyen
authors.affiliation: Department of Psychology, University of Washington, Seattle, WA 98195, United States; Institute for Learning and Brain Sciences (I-LABS), University of Washington, Seattle, WA 98195, United States; Center for Sensorimotor Neural Engineering, University of Washington, Seattle, WA 98195, United States; University of Washington Institute of Neuroengineering (UWIN), Seattle, WA 98195, United States. Electronic address: csprat@uw.edu.
authors.forename: Chantel S
authors.initials: CS
authors.lastname: Prat
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001479:Basal Ganglia / Q000502:physiology*; D003657:Decision Making / Q000502:physiology; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008962:Models, Theoretical; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
keywords: Basal ganglia; Cognitive control; Computational modeling; Prefrontal cortex; Selective attention