Effects of Stress and Task Difficulty on Working Memory and Cortical Networking

Area of Science:

• Neuroscience
• Cognitive Psychology
• Human Adolescent Studies

Background:

• Working memory is crucial for cognitive tasks.
• Stress and task difficulty can significantly impact cognitive performance.
• Understanding brain communication patterns under varying cognitive loads is essential.

Purpose of the Study:

• To investigate the interactive effects of stress and task difficulty on working memory performance.
• To analyze cortico-cortical communication patterns during memory encoding under different stress and difficulty levels.
• To examine how stress influences brain network connectivity during cognitive tasks in adolescents.

Main Methods:

• Thirty-eight adolescents performed easy and hard working memory tasks under low- and high-stress conditions.
• Working memory accuracy and reaction time were measured.
• Electroencephalogram (EEG) coherence (inter- and intrahemispheric) was analyzed during memory encoding.

Main Results:

• Working memory performance (accuracy, reaction time) varied with task difficulty and stress.
• Higher interhemispheric coherence was observed in the easy task at frontal sites.
• Intrahemispheric coherence patterns differed between hemispheres based on task difficulty.
• Both inter- and intrahemispheric coherences were higher under low-stress conditions.
• Significant interactions indicated stress reduced cortical communication more in harder tasks, particularly in the beta frequency band.

Conclusions:

• Stress appears to decrease communication between memory-relevant cortical areas, particularly as task difficulty increases.
• Adolescent brain networks show altered communication patterns under stress and varying task demands.
• Findings highlight the complex interplay between stress, cognitive load, and neural network function.