Auditory-limbic-cerebellum interactions and cognitive impairments in noise-induced hearing loss

Abstract

Aims: This study aimed to explore the neural substrate of hearing loss-related central nervous system in rats and its correlation with cognition.

Methods: We identified the neural mechanism for these debilitating abnormalities by inducing a bilateral hearing loss animal model using intense broadband noise (122 dB of broadband noise for 2 h) and used the Morris water maze test to characterize the behavioral changes at 6 months post-noise exposure. Functional magnetic resonance imaging (fMRI) was conducted to clarify disrupted functional network using bilateral auditory cortex (ACx) as a seed. Structural diffusion tensor imaging (DTI) was applied to illustrate characteristics of fibers in ACx and hippocampus. Pearson correlation was computed behavioral tests and other features.

Results: A deficit in spatial learning/memory, body weight, and negative correlation between them was observed. Functional connectivity revealed weakened coupling within the ACx and inferior colliculus, lateral lemniscus, the primary motor cortex, the olfactory tubercle, hippocampus, and the paraflocculus lobe of the cerebellum. The fiber number and mean length of ACx and different hippocampal subregions were also damaged in hearing loss rats.

Conclusion: A new model of auditory-limbic-cerebellum interactions accounting for noise-induced hearing loss and cognitive impairments is proposed.

Keywords: auditory cortex; cognitive impairment; hippocampus; limbic system; noise-induced hearing loss.