EEG Study on the Neural Patterns of Brain with Music Stimuli: An Evidence of Hysteresis?

A basic and one of the oldest socio-cognitive domains of the human species is music. Listening to music regularly helps keep the neurons and synapses more active. Neurological studies have identified that music is a valuable tool for evaluating the brain system. It has been observed that different parts of the brain are involved in processing music. They include the auditory cortex, frontal cortex, cerebral cortex and even the motor cortex. The objective of this study is to analyze the effect of Hindustani music on brain activity during normal relaxing conditions using electroencephalography (EEG). Two male (age 20-23) healthy subjects without special musical education participated in the study. EEG signals were acquired at the frontal (F3/F4, F7/F8), temporal (T3/T4, T5/T6), central (C3/C4), parietal (P3/P4), and occipital (O1/O2) lobes of the brains listening to music in three conditions, namely rest before music, with music, and after withdrawal of the music. Frequency analysis was done for the alpha and delta brain rhythms. The finding shows that arousal based activities were enhanced while listening to Hindustani music of contrasting emotions (romantic/sorrow) for both the subjects. The important conclusion is that when the music stimuli is removed, discernible alpha and delta brain rhythms remain for some time, showing residual arousal. This is analogous to ‘Hysteresis’ where the system retains some ‘memory’ of the former stimulated state. This was further corroborated by a non linear analysis (Detrended Fluctuation Analysis) of the alpha rhythms.