Sensitivity of the human auditory cortex and reward network to reverberant musical stimuli

A room's acoustics can alter subjective impressions of music, including preference. However, little research has characterized the brain's response to room conditions. Functional magnetic resonance imaging (fMRI) was used to investigate the auditory and reward responses to concert hall stimuli. Before the fMRI testing, 18 participants rated their preferences to a solo-instrumental passage and an orchestral motif simulated in eight room acoustic conditions outside an MRI scanner to identify their most liked and disliked conditions. In the MRI, the most-liked (reverberation time, RT = 1.0-2.8 s) and most-disliked (RT = 7.2 s) conditions, along with the [anechoic and scrambled versions] anechoic and scrambled versions of the musical passages were presented. The auditory cortex was found to be sensitive to the temporal coherence of the stimuli as it exhibited stronger activations for simpler stimuli, i.e., the solo-instrumental and anechoic conditions, than for stimuli containing temporally incoherent auditory objects - the orchestral and reverberant conditions. In contrasts between liked and disliked reverberant stimuli, a reward response in the basal ganglia was detected in a region of interest analysis using a temporal derivative model of the hemodynamic response function. This response may indicate differences in preference between subtle variations in room acoustics applied to the same musical passage.