Fatiguing cognitive exertion increases participants' subjective costs of physical effort compared to a baseline rested state, mediated by signals in the dorsolateral prefrontal cortex.
Does a cognitively fatiguing working memory task alter decisions to exert physical effort in human participants?
Cognitive fatigue increases the subjective cost of physical effort, supported by a general fatigue signal in the brain that integrates exertion-specific information.
Fatigue is a state of exhaustion that influences our willingness to engage in effortful tasks. While both physical and cognitive exertion can cause fatigue, there is a limited understanding of how fatigue in one exertion domain (e.g., cognitive) affects decisions to exert in another (e.g., physical). We use functional magnetic resonance imaging (fMRI) to measure brain activity while human participants make decisions to exert prospective physical effort before and after engaging in a cognitively fatiguing working memory task. Using computational modeling of choice behavior, we show that fatiguing cognitive exertion increases participants' subjective costs of physical effort compared to a baseline rested state. We describe how signals related to fatiguing cognitive exertion in the dorsolateral prefrontal cortex influence physical effort value computations instantiated by the insula, thereby increasing an individual's subjective valuation of prospective physical effort while cognitively fatigued. Our results support the idea of a general fatigue signal that integrates exertion-specific information to guide effort-based choice.
Dryzer et al. (Wed,) conducted a other in Cognitive fatigue. Cognitively fatiguing working memory task vs. Baseline rested state was evaluated on Subjective costs of physical effort and brain activity. Fatiguing cognitive exertion increases participants' subjective costs of physical effort compared to a baseline rested state, mediated by signals in the dorsolateral prefrontal cortex.