The Contribution of Cognitive Control Networks in Word Selection Processing in Parkinson’s Disease: Novel Insights from a Functional Connectivity Study

TL;DR

This study explores how brain networks involved in attention and decision-making affect word selection in early Parkinson’s disease patients.

Contribution

The study provides novel insights into the role of cognitive control networks in word selection among early Parkinson’s disease patients.

Findings

The salience network's connectivity was significantly associated with task performance in Parkinson’s disease patients.

Central executive network connectivity showed a weaker but notable link to tasks requiring selection among more competitors.

Findings support the hypothesis of impaired executive control in early Parkinson’s disease during word selection.

Abstract

Parkinson’s disease (PD) patients are impaired in word production when the word has to be selected among competing alternatives requiring higher attentional resources. In PD, word selection processes are correlated with the structural integrity of the inferior frontal gyrus, which is critical for response selection, and the uncinate fasciculus, which is necessary for processing lexical information. In early PD, we investigated the role of the main cognitive large-scale networks, namely the salience network (SN), the central executive networks (CENs), and the default mode network (DMN), in word selection. Eighteen PD patients and sixteen healthy controls were required to derive nouns from verbs or generate verbs from nouns. Participants also underwent a resting-state functional MRI. Functional connectivity (FC) was examined using independent component analysis. Functional seeds for the SN, CENs, and DMN were defined as spheres, centered at the local activation maximum. Correlations were calculated between the FC of each functional seed and word production. A significant association between SN connectivity and task performance and, with less evidence, between CEN connectivity and the task requiring selection among a larger number of competitors, emerged in the PD group. These findings suggest the involvement of the SN and CEN in word selection in early PD, supporting the hypothesis of impaired executive control.

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