title: The pattern of Fos expression in the rat auditory brainstem changes with the temporal structure of binaural electrical intracochlear stimulation.
abstract: The immediate-early-gene c-fos with its protein product Fos has been used as a powerful tool to investigate neuronal activity and plasticity following sensory stimulation. Fos combines with Jun, another IEG product, to form the dimeric transcription factor activator protein 1 (AP-1) which has been implied in a variety of cellular functions like neuronal plasticity, apoptosis, and regeneration. The intracellular emergence of Fos indicates a functional state of nerve cells directed towards molecular and morphological changes. The central auditory system is construed to detect stimulus intensity, spectral composition, and binaural balance through neurons organized in a complex network of ascending, descending and commissural pathways. Here we compare monaural and binaural electrical intracochlear stimulation (EIS) in normal hearing and early postnatally deafened rats. Binaural stimulation was done either synchronously or asynchronously. The auditory brainstem of hearing and deaf rats responds differently, with a dramatically increasing Fos expression in the deaf group so as if the network had no pre-orientation for how to organize sensory activity. Binaural EIS does not result in a trivial sum of 2 independent monaural EIS, as asynchronous stimulation invokes stronger Fos activation compared to synchronous stimulation almost everywhere in the auditory brainstem. The differential response to synchronicity of the stimulation puts emphasis on the importance of the temporal structure of EIS with respect to its potential for changing brain structure and brain function in stimulus-specific ways.
authors.affiliation: Neurobiological Research Laboratory, Department of Otorhinolaryngology, University-ENT Clinic Freiburg, Germany. Electronic address: till.jakob@uniklinik-freiburg.de.
authors.forename: Till F
authors.initials: TF
authors.lastname: Jakob
authors.affiliation: Neurobiological Research Laboratory, Department of Otorhinolaryngology, University-ENT Clinic Freiburg, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Döring
authors.affiliation: Neurobiological Research Laboratory, Department of Otorhinolaryngology, University-ENT Clinic Freiburg, Germany. Electronic address: robert.illing@uniklinik-freiburg.de.
authors.forename: Robert-Benjamin
authors.initials: RB
authors.lastname: Illing
mesh_terms: D000818:Animals; D001303:Auditory Cortex / Q000187:drug effects / Q000378:metabolism; D001306:Auditory Pathways / Q000187:drug effects / Q000378:metabolism*; D001933:Brain Stem / Q000378:metabolism; D003051:Cochlea / Q000187:drug effects*; D017626:Cochlear Nucleus / Q000187:drug effects / Q000378:metabolism; D003638:Deafness / Q000503:physiopathology; D004558:Electric Stimulation; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects*; D016762:Genes, fos / Q000187:drug effects*; D007245:Inferior Colliculi / Q000187:drug effects / Q000378:metabolism; D008307:Malleus / Q000503:physiopathology; D009847:Olivary Nucleus / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
keywords: Auditory brainstem; Electrical intracochlear stimulation; Fos; Plasticity; Synchronous/asynchronous stimulation