Developmental timing of auditory deprivation influences spatial memory and hippocampal plasticity in rats

Age-dependent sensory deprivation may differentially affect hippocampal integrity, making it essential to investigate how the timing of exposure influences neurodevelopmental outcomes. This study aimed to examine how peripheral auditory deprivation at various ages impacts cognitive functions in rats. Transcanal cochlear ablation was performed at postnatal days (PND) 14, 21, 28, and 60. At four months of age, spatial learning, memory, neurogenesis, and molecular markers associated with synaptic plasticity were evaluated. Compared to controls, all experimental groups-except those ablated at PND 14-exhibited spatial memory deficits, with the most pronounced impairment observed in animals ablated at PND 28 and 60. Correspondingly, hippocampal neurogenesis and synaptic plasticity were significantly reduced in these groups. These changes were age-dependent, with early-life auditory sensory deprivation causing less significant impairment in adulthood. Our study demonstrated an age-dependent effects of auditory deprivation on hippocampal function. The more pronounced reduction in hippocampal function developed in hearing-deprived animals at older ages compared to animals with early-life cochlear ablation. This highlights the importance of age in understanding the cognitive effects of auditory deprivation.