Modularity and flexibility quantify unique processing of music and speech stimuli in the human brain

Music has been shown to have therapeutic benefits for mental health, though few studies have quantified the impact on the brain. We investigated neural network changes from fMRI data while subjects actively listened to a variety of auditory pieces that varied in cultural familiarity and emotivity. We applied theory derived in our group showing that the extent to which modularity and flexibility of the network are selected for depends on the complexity and timescale of the activity being carried out. We found a strong negative correlation between modularity and flexibility while subjects listened to speech; this relationship decreased during self-selected and culturally familiar music, and it became random during culturally unfamiliar music and speech. We also found that modularity during a self-selected song was predictive of the neural network architecture during other pieces. These novel quantifiers of neural activity pave the way for creating individualized predictions of response to music engagement and tailoring therapy interventions to individual patients.