Neural Network During Cognitive Task in the Heat Stressed Individuals

Abstract

Hyperthermia-induced central fatigue impairs exercise performance and cognitive function. We evaluated the effect of hyperthermia on cognitive function using factional magnetic resonance imaging (fMRI)．Eighteen healthy individuals performed two visual cognitive tasks (Go/No-go task and Flanker task in a random order) before (i.e. normothermia) and during heat stress. External canal temperature during heat stress was increased by 1.1℃ from the normothermic condition. Reaction time of each task was shortened during heat stress, but the error rate was not changed. We observed broad activated brain regions, including the dorsolateral and ventrolateral prefrontal cortices, and motor-related areas such as supplementary motor area and premotor area during heat stress rather than during normothermia. These results suggest that heat stress increases the load of neural activity during performing cognitive tasks, relative to the normothermia.