Mental Flexibility: An MEG Investigation in Typically Developing Children
Authors: A. Mogadam, Anne E. Keller, Margot J. Taylor, J. Lerch, E. Anagnostou, E. Pang Journal: Brain and Cognition, 2018, Volume 120, Pages 58-66 DOI: 10.1016/j.bandc.2017.10.001
Abstract
Mental flexibility is a core property of cognitive executive functions, relying on an extended frontoparietal network in the brain. fMRI research comparing typically developing children and adults has found that children from an early age recruit the same “classic” brain areas associated with mental flexibility as adults; however, there is evidence that the timing of activation may be different. To investigate the temporal dynamics of brain activity associated with mental flexibility in children, we recruited 22 typically developing children (8-15 years) to complete a set-shifting task in the MEG. Our results showed that while the children relied on the same frontoparietal network of mental flexibility, there was a different emphasis on active brain regions, with children preferentially using their posterior parietal cortices. Additional areas such as the temporal pole and the premotor areas were also recruited, potentially playing a supporting role. Although children shared the same window of peak activity as adults, 75-350 ms, we found a significant decrease in activation latency with increasing age, suggesting the presence of developmental differences in timing of brain activity in areas supporting mental flexibility during childhood.
MEG-Compatible IED Set-Shifting Task Design
The task is a modified Intradimensional/Extradimensional (ID/ED) set-shifting paradigm adapted for MEG compatibility. Key design features:
Stimuli: Visual shapes presented on a screen, viewed through prism glasses while the subject is in the MEG scanner.
Trial Types:
- Easy Shift (Intradimensional): Within the same stimulus dimension (e.g., shape to shape). Tests basic rule maintenance and reversal.
- Hard Shift (Extradimensional): Across stimulus dimensions (e.g., shape to colour). Tests true cognitive flexibility and set-shifting.
Timing: The critical window of neural activity is 75-350 ms post-stimulus, with activation latency decreasing with age in children aged 8-15.
MEG Adaptation: The task was specifically designed to:
- Minimise head movement (critical for MEG source localisation)
- Use non-magnetic response devices
- Enable rapid event-related design for averaging of MEG trials
- Avoid auditory confounds by using visual only stimuli
Task Figure: The MEG-compatible IED task figure is available at: https://www.researchgate.net/publication/320576153/figure/fig1/AS:867690767974402@1583885008792/MEG-compatible-IED-set-shifting-task-Easy-Shift-trials-involved-intra-dimensional.png
Key Findings for ID/ED Literature
- Children (8-15 years) recruit the same frontoparietal network as adults for set-shifting
- Children preferentially rely on posterior parietal cortices (vs. more frontal in adults)
- Children recruit additional temporal pole and premotor areas as compensatory support
- Peak neural activity window: 75-350 ms
- Developmental finding: Activation latency decreases significantly with increasing age, demonstrating maturation of cognitive flexibility circuits through childhood
Relevance to Depression Research
While this study used typically developing children, the MEG-compatible version of the ID/ED task enables investigation of frontoparietal network dynamics in mood disorders. Given that depressed subjects show perseveration on the standard ID/ED task (inability to flexibly update behaviour when rules change), the MEG-compatible version allows:
- Temporal characterisation of neural deficits (are depression-related deficits in early 75-350ms processing?)
- Source localisation of perseveration (parietal vs frontal contributions)
- Tracking of developmental trajectories in early-onset depression
Related Pages
intradimensional-extradimensional-shift | nonverbal-cognitive-tasks | preclinical-drug-screening