The function of BDNF in the adult auditory system

Abstract

The inner ear of vertebrates is specialized to perceive sound, gravity and movements. Each of the specialized sensory organs within the cochlea (sound) and vestibular system (gravity, head movements) transmits information to specific areas of the brain. During development, brain-derived neurotrophic factor (BDNF) orchestrates the survival and outgrowth of afferent fibers connecting the vestibular organ and those regions in the cochlea that map information for low frequency sound to central auditory nuclei and higher-auditory centers. The role of BDNF in the mature inner ear is less understood. This is mainly due to the fact that constitutive BDNF mutant mice are postnatally lethal. Only in the last few years has the improved technology of performing conditional cell specific deletion of BDNF in vivo allowed the study of the function of BDNF in the mature developed organ. This review provides an overview of the current knowledge of the expression pattern and function of BDNF in the peripheral and central auditory system from just prior to the first auditory experience onwards. A special focus will be put on the differential mechanisms in which BDNF drives refinement of auditory circuitries during the onset of sensory experience and in the adult brain. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.

Keywords: ABR; AC; ACTH; AF; AN; Acoustic trauma; Arc; Auditory system; BDNF; BLA; CN; CRH; Cochlea; Corticotropin-releasing hormone; DCN; EE; EF; HPA axis; IC; IHC; Inhibition; K(v) current; LSO; MGB; MSO; OHC; POMC; Plasticity; SC; SG; SOC; SR; TM; VCN; VHC; activity-regulated gene; adrenocorticotropin hormone; afferent fibre; auditory brainstem response; auditory cortex; auditory nerve; basolateral amygdala; cochlear nucleus; dorsal cochlear nucleus; efferent fibre; environmental enrichment; hypothalamic-pituitary-adrenal axis; inferior colliculus; inner hair cell; lateral superior olive; medial geniculate body; medial superior olive; outer hair cell; pro-opiomelanocortin; spiral ganglion; spontaneous rate; superior olivary complex; supporting cell; tectorial membrane; ventral cochlear nucleus; vestibular hair cell; voltage dependent potassium current.