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Modeling the effects of methylphenidate on conflict, top-down control, and evidence accumulation using the Conflict Linear Ballistic Accumulator


Weigard, A and Heathcote, A and Sripada, CS, Modeling the effects of methylphenidate on conflict, top-down control, and evidence accumulation using the Conflict Linear Ballistic Accumulator, Psychopharmacology, 236, (8) pp. 2501-2512. ISSN 0033-3158 (2019) [Refereed Article]

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Copyright 2019 Springer-Verlag GmbH Germany, part of Springer Nature

DOI: doi:10.1007/s00213-019-05316-x


Rationale: Although methylphenidate and other stimulants have been demonstrated to improve task performance across a variety of domains, a computationally rigorous account of how these drugs alter cognitive processing remains elusive. Recent applications of mathematical models of cognitive processing and electrophysiological methods to this question have suggested that stimulants improve the integrity of evidence accumulation processes for relevant choices, potentially through catecholaminergic modulation of neural signal-to-noise ratios. However, this nascent line of work has thus far been limited to simple perceptual tasks and has largely omitted more complex "conflict" paradigms that contain experimental manipulations of specific top-down interference resolution processes.

Objectives and Methods: To address this gap, this study applied the Conflict Linear Ballistic Accumulator (LBA), a newly proposed model designed for conflict tasks, to data from healthy adults who performed the Multi-Source Interference Task (MSIT) after acute methylphenidate or placebo challenge.

Results: Model-based analyses revealed that methylphenidate improved performance by reducing individuals’ response thresholds and by enhancing evidence accumulation processes across all task conditions, either by improving the quality of evidence or by reducing variability in accumulation processes. In contrast, the drug did not reduce bottom-up interference or selectively facilitate top-down interference resolution processes probed by the experimental conflict manipulation.

Conclusions: Enhancement of evidence accumulation is a biologically plausible and task-general mechanism of stimulant effects on cognition. Moreover, the assumption that methylphenidate’s effects on behavior are only visible with complex "executive" tasks may be misguided.

Item Details

Item Type:Refereed Article
Keywords:methylphenidate, stimulants, evidence accumulation, conflict tasks, executive functions, cognitive modeling, computational psychiatry, Bayesian
Research Division:Psychology
Research Group:Biological psychology
Research Field:Behavioural neuroscience
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in psychology
UTAS Author:Heathcote, A (Professor Andrew Heathcote)
ID Code:133589
Year Published:2019
Web of Science® Times Cited:3
Deposited By:Psychology
Deposited On:2019-07-02
Last Modified:2020-08-18
Downloads:5 View Download Statistics

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