Changes in brain rhythms evoked by music listening: EEG analysis and correlation with psychometric parameters

The use of music in clinical settings for patients suffering from various disorders and conditions has become a well-established practice, with documented benefits. Moreover, research has demonstrated that music can evoke specific emotional states in listeners and activate various cognitive functions, including memory, language, attention, and perception. The aim of this thesis is to present experimental evidence on the music’s effects on the brain, focusing in particular on the correlation between emotional responses elicited by musical pieces and variations in brain rhythms. EEG recordings from three subjects were analyzed under three conditions: a two-minute period of eyes-closed rest before and after listening to music, and during ten listening sessions, also with eyes closed. Each musical piece lasted one minute, and after each session, participants rated the intensity of various emotions on a scale from 1 to 10. The analysis focused on the ratings for “nostalgia”, “sadness”, “serenity”, and “joy”. After preprocessing the data, the spectral power was calculated for each condition in the alpha, beta, theta, and delta frequency bands. For the pre- and post-listening resting periods, the topographic maps of each rhythm were compared; the analysis did not reveal any significant differences in brain rhythms between the pre- and post-music conditions. Spearman’s correlation was computed between the emotional responses for each musical piece and the relative power in each frequency band across all 61 EEG channels. In this analysis, significant and highly heterogeneous correlation patterns emerged across the subjects. In accordance with the scientific literature, frontal lateralization was observed in two of the three subjects in the delta rhythm, as the amplitude of the EEG signal in the right frontal area was negatively correlated with negative emotions (i.e. sadness and nostalgia). The alpha rhythm exhibited lateralization only in subject RO9, with negative correlations in the left hemisphere for positive emotions such as joy and serenity, and positive correlations in the left hemisphere for negative emotions such as sadness and nostalgia. The theta and beta bands, on the other hand, displayed much more heterogeneous patterns between the participants. These results highlight that, despite the progress made so far, there is still much to uncover about the link between music-evoked emotions and brain responses.