Hyperthermia does not alter the increase in cerebral perfusion during cognitive activation

Area of Science:

• Physiology
• Neuroscience
• Thermoregulation

Background:

• Cognitive activation typically increases cerebral perfusion to meet metabolic demands.
• The impact of hyperthermia (elevated body temperature) on this cerebrovascular response is not fully understood.
• Understanding this interaction is crucial for various physiological and clinical contexts.

Purpose of the Study:

• To investigate whether hyperthermia attenuates the increase in cerebral perfusion during cognitive activation.
• To examine the effect of elevated body temperature on cerebral blood flow regulation during a working memory task.

Main Methods:

• Measured mean middle cerebral artery blood velocity (MCAV(mean)) as an index of cerebral perfusion.
• Utilized the nBack test, a measure of working memory, as the cognitive task.
• Induced hyperthermia and monitored physiological parameters including skin and intestinal temperatures, mean arterial pressure, and end-tidal CO2.

Main Results:

• Hyperthermia was confirmed by significant increases in skin and intestinal temperatures.
• Physiological changes during hyperthermia included reductions in mean arterial pressure and end-tidal CO2.
• Contrary to the hypothesis, hyperthermia did not affect nBack test performance or the increase in MCAV(mean) during cognitive activation.

Conclusions:

• The capacity to increase cerebral perfusion during cognitive activation remains unaffected by hyperthermia.
• Cerebral blood flow regulation during working memory tasks is robust to moderate elevations in body temperature.
• These findings challenge the notion that hyperthermia impairs cerebrovascular responses to cognitive challenges.