Children who blink more, think more.
Researchers found that spontaneous and rapid eye-blinking is a sign of higher performance on cognitive flexibility tasks in children aged 3-6.
The association is linked to brain activation in the right dorsolateral prefrontal cortex (dIPFC), which controls executive functioning for planning and focus.
Spontaneous eye-blink rate (sEBR) is a dopamine marker in children and was found to correlate with high executive functioning in preschool-aged children when performing the study.
Researchers recruited 113 children from Japan, aged 3-6, to participate in a classic cognitive flexibility test: a card-sorting game where the rules change partway through from sorting by color to sorting by shape.
This task measures how well a child can drop one way of thinking and pick up another, a major building block for impulse control.
Researchers used functional near-infrared spectroscopy (fNIRS) imaging, a non-invasive optical technique that uses near-infrared light to measure blood oxygen levels and activity in the brain, to see when the area was activated.
They found that there was more activity in the dIPFC, a key region known to support the ability to switch rules.
Scientists looked at brain activity using fNIRS and simultaneously recorded children’s spontaneous eye-blink rate using ordinary video cameras. The light-based brain imaging technique shines light through the scalp to measure blood flow changes in the brain.
The scientists found that spontaneous blinking occurs in the same window as the higher brain activity in the dIPFC.
Spontaneous eye-blinking occurs outside of conscious awareness and is influenced by brain neuromodulatory systems — in this case, dopamine signaling to the brain. People with Parkinson’s disease, which involves disrupted dopamine signaling, tend to blink far less often and also struggle with switching between tasks.
Results showed that children who blinked more performed better in the card game. The statistic remained true when scientists analyzed each age group individually, indicating that blink rate was the true marker for cognitive ability rather than general age maturity.
Blink rates climb between ages 1 and 5. In the study, youngest children blinked at low, similar rates. but children on the older end had pronounced blinking variations, with highest performers blinking more than 20 times per minute.
The study also confirmed that the dIPFC is the primary active brain area during rule-switching tasks, as no correlation was found with other brain subregions of the prefrontal cortex. Older children had more specialized activation in the region, suggesting that the increase in sEBR is associated with more functional differentiation of task-relevant brain networks.
Older children with higher blink rates and better cognitive flexibility exhibited more focused dIPFC activation, suggesting sEBR is an indicator of prefrontal “functional differentiation”, or the healthy specialization of task-relevant brain networks.
Preschool age is critical for rapid development of adaptable executive functioning skills like regulating impulses and following directions. Differences in EF abilities are strong predictors of academic and social competence and health.
Assessing eye-blinking — and the simplicity of doing so — is promising for future pediatric research and care. sEBR can be accurately calculated inexpensively, so it could become a noninvasive indicator for tracking brain functioning.
Scientists have long struggled to peek inside the brains of young children who are squirmy or nervous to have a brain scan or invasive procedure. Researchers, teachers and parents can now use this simple new way to check a child’s developing mind.
That said, blinking won’t be able to replace brain scans or behavioral testing. It is now seen by researchers as a potential marker worth exploring further, but not a fully developed tool.
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