Mental fatigue: costs and benefits

Area of Science:

• Neuroscience
• Cognitive Psychology
• Decision Making

Background:

• Adaptive behavior relies on evaluating predicted rewards and potential risks.
• Motivated behaviors, driven by rewards or punishments, incur energetic costs.
• Understanding mental fatigue requires examining the interplay of reward and cost assessment.

Purpose of the Study:

• To propose a framework for understanding mental fatigue.
• To integrate the evaluation of expected rewards and energetic costs in task performance.
• To identify key brain regions involved in this evaluation process.

Main Methods:

• Review of existing findings on brain regions involved in reward and cost evaluation.
• Analysis of how these regions contribute to motivated behavior and energetic expenditure.
• Conceptual integration of these findings into a unified framework for mental fatigue.

Main Results:

• The nucleus accumbens, orbitofrontal cortex, amygdala, insula, and anterior cingulate cortex are implicated in evaluating task rewards and energetic demands.
• Behavioral continuation depends on a favorable balance favoring energy expenditure.
• Mental fatigue arises when perceived energetic costs exceed predicted rewards.

Conclusions:

• A novel framework for mental fatigue is proposed, centering on the integrated evaluation of rewards and costs.
• This framework highlights the neural basis of decision-making under energetic constraints.
• Mental fatigue is characterized by a motivational shift when costs are perceived to outweigh rewards.