Working memory improves developmentally as neural processes stabilize.

David Florentino Montez,Finnegan J. Calabro,Beatriz Luna,Elaine Astrand

doi:10.1371/journal.pone.0213010

David Florentino Montez, Finnegan J. Calabro + Show 2 more

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https://doi.org/10.1371/journal.pone.0213010

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Abstract

Working memory performance is a key indicator of cognitive and developmental status. While recent evidence indicates that stabilizing neural gain supports the stabilization of working memory during adolescence, the computational mechanisms linking neural stabilization to behavior are poorly understood. We develop a mechanistic account of behavior during the memory-guided saccade task based on a stochastic accumulator framework. Results indicate that a specific balance of independent gain signals affecting working memory representations and oculomotor response thresholds can account for a peculiar U-shaped feature of the speed-accuracy relationship. Additionally, aspects of behavioral variability and mean behavioral performance, as well as subtle shifts in the shape of the speed-accuracy relationship across development, can be accounted for by the stabilization of these two sources of variability. Thus, the stabilization of neural variability can, in part, account for developmental improvements in behavioral variability as well as some improvement in mean behavioral performance.

Highlights

Adolescent cognitive development is marked by stabilizing behavioral responses which occur alongside improvements in mean behavioral performance
We formalize a computational account of our hypothesis based on a high-dimensional drift-diffusion, or race model, framework that models a continuous range of response outcomes, and demonstrate that the U-shaped speed accuracy relationship that we observed in the memory-guided saccade task can arise from the appropriate balance of two independent sources of neural gain variability
Understanding the computational principles underlying working memory (WM) processes and their influence on behavior is key to understanding the nature of the changes that occur in the brain during normative development and during the emergence of many psychiatric disorders

Summary

Introduction

Adolescent cognitive development is marked by stabilizing behavioral responses which occur alongside improvements in mean behavioral performance This is seen, for instance, in the tendency for developmental trajectories of decreasing average reaction times and increasing accuracy to occur in tandem with commensurate decreases in the trial-to-trial variability of those measures [1,2,3,4]. These developmental changes are especially apparent in tasks that place demands upon cognitive processes, such as working memory (WM), and as such, metrics of mean behavioral performance and trial-to-trial behavioral variability are both often used as barometers of cognitive functioning and are widely employed as surrogate measures of developmental status or cognitive impairment [5,6,7].

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