Developmental hearing loss-induced perceptual deficits are rescued by cortical expression of GABA_B receptors

Even transient periods of developmental hearing loss during the developmental critical period have been linked to long-lasting deficits in auditory perception, including temporal and spectral processing, which correlate with speech perception and educational attainment. In gerbils, hearing loss-induced perceptual deficits are correlated with a reduction of both ionotropic GABA_A and metabotropic GABA_B receptor-mediated synaptic inhibition in auditory cortex, but most research on critical period plasticity has focused on GABA_A receptors. We developed viral vectors to express both endogenous GABA_A or GABA_B receptor subunits in auditory cortex and tested their capacity to restore perception of temporal and spectral auditory cues following critical period hearing loss in the Mongolian gerbil. HL significantly impaired perception of both temporal and spectral auditory cues. While both vectors similarly increased IPSCs in auditory cortex, only overexpression of GABA_B receptors improved perceptual thresholds after HL to be similar to those of animals without developmental hearing loss. These findings identify the GABA_B receptor as an important regulator of sensory perception in cortex and point to potential therapeutic targets for developmental sensory disorders.