Mental exhaustion after intense cognitive work is real—and now we have brain scans to prove it.
In a2022 study, neuroscientists used magnetic resonance spectroscopy to analyze chemical changes in the brain as young adults carried out demanding cognitive tasks like classifying letters as vowels or consonants over a grueling, 6-hour period. As the day wore on, “potentially toxic by-products” accumulated in the participants’ prefrontal cortex—the region of the brain responsible for executive function skills like decision-making, planning, and attention.
Eventually, the toxins triggered “a metabolic regulation mechanism”—akin to a car’s “maintenance required” light—that signaled the brain to shift gears, redirecting energy away from higher-order cognitive tasks in favor of activities requiring less cognitive effort.
That feeling of being mentally exhausted after a day of thinking hard? It’s not a mirage, the neuroscientists say—it’s a biochemical nudge urging us to shelve important decisions until we’ve had a good rest.
Your Brain’s “Maintenance Required” Light Is On
by Michael Keany
Sep 19, 2022
Your Brain’s “Maintenance Required” Light Is On
Edutopia
Mental exhaustion after intense cognitive work is real—and now we have brain scans to prove it.
In a 2022 study, neuroscientists used magnetic resonance spectroscopy to analyze chemical changes in the brain as young adults carried out demanding cognitive tasks like classifying letters as vowels or consonants over a grueling, 6-hour period. As the day wore on, “potentially toxic by-products” accumulated in the participants’ prefrontal cortex—the region of the brain responsible for executive function skills like decision-making, planning, and attention.
Eventually, the toxins triggered “a metabolic regulation mechanism”—akin to a car’s “maintenance required” light—that signaled the brain to shift gears, redirecting energy away from higher-order cognitive tasks in favor of activities requiring less cognitive effort.
That feeling of being mentally exhausted after a day of thinking hard? It’s not a mirage, the neuroscientists say—it’s a biochemical nudge urging us to shelve important decisions until we’ve had a good rest.