title: Cochlear injury and adaptive plasticity of the auditory cortex.
abstract: Growing evidence suggests that cochlear stressors as noise exposure and aging can induce homeostatic/maladaptive changes in the central auditory system from the brainstem to the cortex. Studies centered on such changes have revealed several mechanisms that operate in the context of sensory disruption after insult (noise trauma, drug-, or age-related injury). The oxidative stress is central to current theories of induced sensory-neural hearing loss and aging, and interventions to attenuate the hearing loss are based on antioxidant agent. The present review addresses the recent literature on the alterations in hair cells and spiral ganglion neurons due to noise-induced oxidative stress in the cochlea, as well on the impact of cochlear damage on the auditory cortex neurons. The emerging image emphasizes that noise-induced deafferentation and upward spread of cochlear damage is associated with the altered dendritic architecture of auditory pyramidal neurons. The cortical modifications may be reversed by treatment with antioxidants counteracting the cochlear redox imbalance. These findings open new therapeutic approaches to treat the functional consequences of the cortical reorganization following cochlear damage.
authors.affiliation: Department of Head and Neck Surgery, Medical School, Catholic University of the Sacred Heart , Rome , Italy.
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Fetoni
authors.affiliation: Institute of Human Physiology, Medical School, Catholic University of the Sacred Heart , Rome , Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: Troiani
authors.affiliation: Department of Psychology, Sapienza University of Rome and IRCCS Santa Lucia Foundation , Rome , Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Petrosini
authors.affiliation: Department of Head and Neck Surgery, Medical School, Catholic University of the Sacred Heart , Rome , Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Paludetti
keywords: auditory cortex; noise-induced hearing loss; oxidative stress; presbycusis; pyramidal neurons