The Neurodynamics of Working Memory During a Stress Induced State

Abstract

Purpose: Currently the mechanisms the brain uses for various processes are not well understood; the bio-electrical system is complex. The purpose of the current study is to measure the electrical activity of the brain during a working memory task pre- and post-stressor. Method: The participants’ negative affect (PANAS; Watson, Clark, & Tellegen, 1988), and stress (SRQ; Edwards, Edwards, & Lyvers, 2015) scores were measured after the baseline, after the stressor tasks, and at the end of the study. EEG data was collected during a baseline, a working memory task pre-stressor condition, and a working memory task post-stressor condition. Results: Results indicated no significant interaction between Time x Location x Band. However, there was marginal significance at the Time x Band interaction level, providing marginal support for the idea that the brain enters different band wave frequencies for different tasks, and while in different emotional states. During each time condition, there was a decrease in alpha compared to the preceding time condition. A further look showed marginal significance at the band level, and found significance at the location level. The analysis on the median reaction time during the pre-modified Sternberg working memory task (pre-MSWM) and post-modified Sternberg working memory task (post-MSWM) conditions was marginally significant. There was a decrease in median reaction during the post-MSWM condition compared to the pre-MSWM condition. Further, there was marginal significance in the alpha amplitude between location Fp1 and Fp2 during the post-MSWM condition. Alpha was highest at location Fp1 during both the pre- and post-MSWM conditions. Alpha asymmetry decreased in the post-MSWM condition compared to the pre-MSWM condition. Conclusion: There was a decrease in alpha during each time condition compared to the preceding time condition. The alpha asymmetry pattern was consistent with previous studies in individuals with chronic stress. There was as decreased in median reaction time during the post-MSWM condition compared to the pre-MSWM condition, which is inverse of what was expected. This could possibly be explained by the participants reaching a peak performance level on the stress-performance curve, there could have been a practice effect that occurred, or possibly a combination of both. Limits on sample size greatly reduced the power of this study. It would be beneficial to conduct similar studies that could aid in understanding the mechanisms the brain uses during various processes.