Theta oscillations in 4-year-olds are sensitive to task engagement and task demands

Marlene Meyer,Sabine Hunnius,Hinke M. Endedijk,Freek van Ede

doi:10.1038/s41598-019-42615-x

Abstract

Top-down control processes are essential for guiding attention and working memory towards task-relevant information. Recently, theta oscillations were suggested as critical for these cognitive processes. Infant studies testing a mixture of bottom-up and top-down processes support adult theta findings. Yet, since infants cannot be instructed, it remains unclear to what extent theta oscillations are involved particularly in top-down control in early childhood. That is especially relevant towards school age when children need top-down control to solve the increasingly complex tasks. In this EEG study, we investigated whether theta-power in 4-year-olds is sensitive to task engagement and to different cognitive task demands. In a within-subjects design, children had three different instructions before watching videos including either no demands (No Task), language-related (Color-naming Task), or action-related (Imitation Task) demands. We analyzed children’s theta-power (3–6 Hz) in two contrasts: (1) Task vs. No Task and (2) Color-naming vs. Imitation Task. The findings revealed more frontomedial theta-power when children were engaged in a task and their frontomedial theta-power increased during their cognitive engagement. Theta-power was stronger over left fronto-temporal sites for language- compared to action-related demands. These findings support recent theoretical work highlighting theta oscillations in top-down control and extend this neurocognitive framework to preschoolers.

Highlights

Theta oscillations in the brain and their potential functional role have fascinated cognitive neuroscientists for decades and motivated extensive research in the field of attention, memory and conflict monitoring
We investigated whether the involvement of frontal theta oscillations in task-relevant processing such as task engagement and different task demands is traceable in young children despite the immaturity of their medial frontal brain areas
The current findings suggest that top-down control required by task engagement modulates frontomedial theta power in young children

Summary

Introduction

Theta oscillations in the brain and their potential functional role have fascinated cognitive neuroscientists for decades and motivated extensive research in the field of attention, memory and conflict monitoring. Zhang and colleagues[24] showed increased frontal theta in 6- to 12-month-old infants in reaction to exaggerated (i.e. infant-directed) compared to non-exaggerated speech Together, these findings suggest that already early in life theta oscillations are likely modulated by stimulus-driven changes in attention potentially including aspects of top-down control. While the findings suggest that theta oscillations might be involved in top-down control early in life, infant studies like these are inherently limited by the constraint that tasks cannot be externally imposed through instruction In this case the studies used contrasts between different stimuli (occlusion period vs period during which a person was present) to investigate sustained attention. Theta power was higher during toy exploration and the presentation of child-directed speech as compared to a baseline

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