Electroencephalographic Signature of Negative Self Perceptions in Medical Students.

Richard M Millis,Allison Palacios,Grace L Millis,Justin Arcaro

doi:10.7759/cureus.22675

Abstract

Frontal alpha asymmetry (fAA) is purported to be a neurophysiological marker for anxiety and depression. Higher left frontal alpha EEG voltage is associated with lower left and higher right frontal cerebral cortical activation, indicative of right-sided fAA. This pilot study tests the hypothesis that greater left-sided frontal alpha voltage is associated with negative thoughts about oneself. A group of eight healthy 28-41-year-old right-handed male medical students were subjected to an extensive interactive self-report inventory (ISI) evaluating perceptions of their psychosocial interactions. Quantitative EEG (qEEG) was performed with eyes closed. Computations of fAA and related parameters were based on measurements in the alpha bandwidth (8-13 Hz) at the left frontal F7 and right frontal F8 scalp electrodes. fAA was the percent difference between mean voltages at F8 minus that at F7. Significance of associations between fAA and the ISI scores was determined by Pearson’s product-moment correlation coefficient, at P≤0.05. “Depressed” scores were positively correlated with right-sided fAA (P=0.01). “Relaxed” (P=0.05), “regulated” (P=0.02), “cooperative” (P=0.05) and “dependent scores” (P=0.004) were negatively correlated with right-sided fAA. These findings imply that right-sided fAA may be associated with more perceptions of “depressed” psychosocial interactions involving negative thoughts about oneself, as well as, more reliance on others (“dependence” score), less sharing (“cooperative” ISI score), less trust (“regulated” ISI score) and less initiative (“relaxed” ISI score). These results support the hypothesis that right-sided fAA may identify individuals with a predilection for negative thoughts about themselves and other negatively-valenced perceptions of their psychosocial interactions.

Highlights

In terms of alpha wave voltage, greater activation of the left frontal lobe is associated with lower frontal alpha voltage on the left than on the right, and is interpreted as dominant hemispheric, left-sided Frontal alpha asymmetry (fAA) [6,7]
Negative frontal alpha asymmetry values indicate larger mean alpha voltage recorded from F7 on the scalp overlying the left frontal cerebral cortex than from F8 overlying the right cortex, interpreted as lower left than right frontal alpha activity; right-sided frontal alpha asymmetry
Negative frontal alpha asymmetry values indicate larger mean alpha voltage recorded from F7 on the scalp overlying the left frontal cerebral cortex than from F8 overlying the right cortex, interpreted as lower left than right frontal alpha activity; rightsided frontal alpha asymmetry

Summary

Introduction

Neural oscillations in the alpha range (8-12 Hz) can be observed at any site of the scalp overlying the brain, and are, generally, inversely related to the activation level of the underlying cerebral cortex [1]. The earliest demonstration of fAA shows a relationship between greater activation of the left than the right cerebral hemispheres when observing emotion-laden televised scenes rated as positive [5]. In unprecedented fashion, this suggests the dominance of the left hemisphere for positive emotions and the dominance of the right hemisphere for negative emotions. The specificity of fAA is suggested by findings that alpha wave voltages measured at scalp electrodes overlying the right and left parietal and occipital lobes fail to discriminate between positive and negative ratings of emotion-laden televised scenes [8]

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Conclusion