Morphological Correlates of Music-Induced Plasticity in the Central Auditory System

Music exposure may promote neuroplasticity that affects emotional processing pathways, auditory discrimination, and cognitive development. To determine the potential underlying mechanisms, histological and molecular methodologies were employed to assess neuroanatomical adaptations in feline auditory pathways. Using Nissl staining, immunohistochemistry and western blotting, we measured and compared total neuronal density, GABAergic interneuron density, the ratio of GABAergic to total neurons and levels of GABA_A receptor and NMDAR1 proteins between controlled music stimulation and ambient noise. We found that the overall neuronal distribution was comparable between the two groups. However, the music-exposed group displayed a 1.38-fold increase in GABAergic interneuron density compared to controls. Stratified cortical analysis revealed layer-specific elevations in GABAergic proportions, with an increase of 1.29-fold and 1.22-fold in Layers IV and V, respectively. We further demonstrated a concurrent upregulation of inhibitory and excitatory signaling components, showing a 2.1-fold increase in GABA_A receptor expression and a 1.8-fold increase in NMDAR1 expression. These structural changes suggest a dual mechanism involving amplified GABA-mediated inhibition and potentiated glutamate-driven excitation in the primary auditory cortex. The rebalanced excitation-inhibition ratio may refine thalamocortical signal processing that enhances spectral-temporal resolution for complex acoustic stimuli. Our findings establish cytoarchitectural correlates for music-induced neuroadaptation, offering insights into the structural underpinnings of auditory-emotional integration in feline models.