Does Right Hemisphere Dominance Relate to Emotional Flexibility and Depressive Moods?

Abstract

Introduction

Studies have shown that depressive traits are usually accompanied by anxiety and stress, contributing lower to emotional flexibility (EF). EF is the ability to have flexible and appropriate responses to changing emotional circumstances [1]. According to the Valence hypothesis, the right brain hemisphere is responsible for processing negative thoughts and emotions, and the left hemisphere for happiness and excitement. Depressive mood is linked to hemisphere imbalance, with the left hemisphere relatively hypoactive and the right hemisphere hyperactive, which is seen in the frontal hemisphere alpha asymmetry [2]. The goal is to explore the relationship between depressive mood, EF, and alpha asymmetry in young adults. We aim to investigate whether frontal asymmetry with higher activity in the right frontal hemisphere is correlated to depressive mood with anxiety and stress, and lower EF.

Methods

The experiment involved 35 adults between the ages of 18 to 27. To evaluate participants’ depressive mood, we used the simple, reliable, and well-used Depression Anxiety Stress Scale (DASS-21) self-reporting questionnaire. EF was measured with the Emotional Shifting Task (EST), a new, more ecologically valid way to measure EF; containing stimuli of positive and negative valence with shift and non-shift conditions. Brain activity in the resting state was recorded with electroencephalography (EEG). Frontal brain activity will be compared between hemispheres through the calculation of the frontal alpha asymmetry index, obtained using the EEGLAB toolbox. We will use linear regression to determine the relation of alpha asymmetry to EST and DASS-21.

Expected results

Based on the literature presented in the introduction [2], and with research showing decreased cognitive flexibility in patients with depression [1]; we hypothesize that participants with a higher score on the DASS-21, slower and less correct responses in the shift conditions on the EST will show stronger alpha asymmetry with right frontal hemisphere being more active than the left.

Conclusion

With further analysis, we aim to add valuable information to the literature about alpha asymmetry’s relation to lower EF and depressive mood, as the research on alpha asymmetry is somewhat inconclusive. With this research, we will contribute to a larger set of studies featuring depressive traits and EF from a neuroscientific point of view.

References

[1] N. Horato, L. A. Quagliato, and A. E. Nardi, “The relationship between emotional regulation and hemispheric lateralization in depression: A systematic review and a meta-analysis,” Translational Psychiatry, vol. 12, no. 162, 2022. doi:10.1038/s41398-022-01927-9

[2] D. Mathersul, L. M. Williams, P. J. Hopkinson, and A. H. Kemp, “Investigating models of affect: Relationships among EEG alpha asymmetry, depression, and anxiety.,” Emotion, vol. 8, no. 4, pp. 560–572, 2008. doi:10.1037/a0012811