Investigating the effect of emotional music on brain activity dynamics

The brain exhibits characteristics of a complex dynamic system in processing external and internal stimuli. A holistic investigation of the whole brain as a self-organising system characterised by spontaneous and non-linear dynamics is therefore required. This seems contrary to the more localistic assumption that focuses attention on individual brain areas in information processing. One way of conceptualising holistic brain dynamics is the idea of metastability. Metastability shows a self-organised dynamic of the brain between integration and segregation, which leads to an optimal and fast response to information processing. To investigate the change in complex and dynamic organisation, this study investigated the relationship between emotionally perceived stimuli, specifically emotional music, and dynamic brain activity. Emotions serve as a good indicator of when the body's homeostasis needs to be restored or when the body is in danger. This links emotions to metastability, which ensures optimal information processing when the body is in a comfortable state. Therefore, this study investigated whether the complexity of brain dynamics differs between the two emotions happiness and sadness. For the manipulation of emotional perception, twelve happy instrumental musical clips and twelve sad instrumental musical clips were played to participants. These were kept constant on their tempo in both conditions. The sample consisted of 25 participants who listened to all songs consecutively while recording their electroencephalography (EEG). The EEG data were analysed in a whole-brain manner through EEG microstates analysis. EEG microstates show quasi-stable states and can therefore be a good measure of holistically changing brain dynamics. Contrary to the expected hypothesis, no differences in complexity and temporal-spatial dynamics were found. This is contrary to most of the previous findings, which are however not consistent. Nonetheless, the data has some limitations, especially in terms of data quality, and therefore the interpretation of the results should be treated with caution.