A Method for Investigating Age-related Differences in the Functional Connectivity of Cognitive Control Networks Associated with Dimensional Change Card Sort Performance

Summary

This video presents a method of examining age-related changes in functional connectivity of cognitive control networks engaged by targeted tasks/processes. The technique is based on multi-variate analysis of fMRI data.

Abstract

The ability to adjust behavior to sudden changes in the environment develops gradually in childhood and adolescence. For example, in the Dimensional Change Card Sort task, participants switch from sorting cards one way, such as shape, to sorting them a different way, such as color. Adjusting behavior in this way exacts a small performance cost, or switch cost, such that responses are typically slower and more error-prone on switch trials in which the sorting rule changes as compared to repeat trials in which the sorting rule remains the same. The ability to flexibly adjust behavior is often said to develop gradually, in part because behavioral costs such as switch costs typically decrease with increasing age. Why aspects of higher-order cognition, such as behavioral flexibility, develop so gradually remains an open question. One hypothesis is that these changes occur in association with functional changes in broad-scale cognitive control networks. On this view, complex mental operations, such as switching, involve rapid interactions between several distributed brain regions, including those that update and maintain task rules, re-orient attention, and select behaviors. With development, functional connections between these regions strengthen, leading to faster and more efficient switching operations. The current video describes a method of testing this hypothesis through the collection and multivariate analysis of fMRI data from participants of different ages.

Introduction

The ability to regulate behavior develops gradually in childhood and adolescence (for review, see Diamond¹). In the Dimensional Change Card Sort task, for example, participants switch from sorting cards one way, such as shape, to sorting them a different way, such as color² (see Figure 2). Switching exacts a small performance cost, or switch cost, such that responses are typically slower and more error-prone on switch trials in which the sorting rule changes as compared to repeat trials in which the sorting rule remains the same³. The magnitude of these costs typically gets smaller as children grow older⁴, i....

Protocol

1. Obtain Approval for Working with Human Subjects

2. fMRI Data Acquisition

1. Acquire fMRI data following procedures suitable for young children (see Raschle, et al.¹²). Make every effort to limit possible age-related differences in task performance and motion, as these differences introduce unwanted confounds that limit one's capacity to draw inferences about developmentally-relevant differences in brain activation and functional connectivity.
   Note: In the current protocol, a repeated-trials version of the DCCS was administered in the form of a block design¹³. Each run includes two 8-trial ....

Results

Group ICA, even on a relatively small fMRI data set, will return a set of components comparable to those observed in other studies. Figure 4 is a superimposition of 5 such components and their associated time courses unmixed from a sample of 12 children and 13 adults, with approximately 800 volumes per participant. As shown in Figure 4, default mode, fronto-parietal, cingulo-insular, and visual networks can readily be seen from the results of this decomposition. As well, notice how easy .......

Discussion

Higher-order mental operations, such as the ability to switch sorting rules, develop rapidly throughout childhood and adolescence. Because these mental operations involve interactions between multiple distributed brain regions, there is growing interest in exploring the relationship between the development of higher-order cognition and age-related changes in the organization of broad-scale cortical networks. We present a method based on group independent component analysis applied to task-based fMRI data as a means of ex.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
SPM8	The MathWorks, Inc.	R2013a