Can the developing auditory system adapt to hearing loss using multiple adaptive strategies? A hearing loss in one ear changes some of the cues to sound location (the binaural cues that rely on differences between the sound heard by each ear) but leaves others intact (the cues that rely only on the sound heard by the ear with normal hearing). Previously, we showed that developing ferrets adapt to a hearing loss in one ear by learning to rely more on the cues to sound location that are unaffected by hearing loss. We now show that these ferrets can also localize sounds correctly using the cues that have been changed by hearing loss. This means that the developing brain (primary auditory cortex) can use multiple adaptive strategies to adapt to hearing loss. It also helps explain some of the apparent differences between experiments in birds and mammals. This suggests that many different species may use the same adaptive strategies. Finally, our results provide insight into the way in which sound location is represented by populations of neurons in the brain. Previous work had suggested that sound location is represented by the difference in neural activity between the two hemispheres. Although this may be true at the level of the brainstem, it does not appear to be true in the cortex.
Keating P, Dahmen JC, King AJ (2015) Complementary adaptive processes contribute to the developmental plasticity of spatial hearing. Nature Neuroscience 18:185-187.
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UCL Ear Institute 