Effects of Auditory Training on Parvalbumin-Expressing Interneurons in Brain Regions Associated with Task Demands

Perceptual training is characterized by strong task and stimulus specificities, leading prior studies on auditory training-induced effects to focus predominantly on the auditory system, particularly the auditory cortex. However, it remains unclear whether such training-induced effects extend beyond the auditory cortex to other brain regions involved in task-related processing. In this study, we trained adult rats on an auditory cue-based discrimination task and then examined post-training changes in the densities of parvalbumin-expressing (PV+) interneurons, a key marker of GABAergic inhibition, across the inferior colliculus (IC), hippocampus, medial prefrontal cortex (mPFC), and basolateral amygdala (BLA)—all of which are implicated in task demands. We found that training significantly increased the PV+ interneuron density in the dentate gyrus of the hippocampus but decreased it in the basal nucleus of the BLA; however, no significant changes were detected in the IC or mPFC. The findings revealed region-specific effects of auditory training on inhibitory circuits mediated by PV+ interneurons, demonstrating that training-induced effects extend beyond the auditory cortex to other brain regions linked to task-related processing. This highlights the potential of auditory training as a strategy for remodeling integrated sensory and cognitive functions in older children and adults.