Monaural deprivation disrupts development of binaural selectivity in auditory midbrain and cortex.
Degraded sensory experience during critical periods of development can have adverse effects on brain function. In the auditory system, conductive hearing loss associated with childhood ear infections can produce long-lasting deficits in auditory perceptual acuity, much like amblyopia in the visual system. Here we explore the neural mechanisms that may underlie "amblyaudio" by inducing reversible monaural deprivation (MD) in infant, juvenile, and adult rats. MD distorted tonotopic maps, weakened the deprived ear's representation, strengthened the open ear's representation, and disrupted binaural integration of interaural level differences (ILD). Bidirectional plasticity effects were strictly governed by critical periods, were more strongly expressed in primary auditory cortex than inferior colliculus, and directly impacted neural coding accuracy. These findings highlight a remarkable degree of competitive plasticity between aural representations and suggest that the enduring perceptual sequelae of childhood hearing loss might be traced to maladaptive plasticity during critical periods of auditory cortex development.
Popescu
Maria V
MV
Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Polley
Daniel B
DB
D000161:Acoustic Stimulation / Q000379:methods; D000200:Action Potentials / Q000502:physiology; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001303:Auditory Cortex / Q000166:cytology / Q000254:growth & development / Q000503:physiopathology*; D001306:Auditory Pathways / Q000254:growth & development / Q000503:physiopathology; D001931:Brain Mapping; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006312:Hearing Loss, Bilateral / Q000209:etiology* / Q000473:pathology*; D008297:Male; D008636:Mesencephalon / Q000166:cytology / Q000254:growth & development / Q000503:physiopathology*; D011571:Psychoacoustics; D051381:Rats; D017207:Rats, Sprague-Dawley; D012683:Sensory Deprivation / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000502:physiology; D013017:Sound Localization / Q000502:physiology; D013997:Time Factors