gms | German Medical Science

81st Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

12.05. - 16.05.2010, Wiesbaden

Nonlinear development of the c-Fos expressing populations of neurons under monotone CI-stimulation

Meeting Abstract

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. 81st Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. Wiesbaden, 12.-16.05.2010. Düsseldorf: German Medical Science GMS Publishing House; 2010. Doc10hno063

DOI: 10.3205/10hno063, URN: urn:nbn:de:0183-10hno0633

Published: July 6, 2010

© 2010 Roßkothen-Kuhl et al.
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Outline

Text

Introduction: The immediate-early-gene c-fos is one of the first genes to be expressed in the auditory system following sensory or electrical cochlea stimulation. As component of the activator-protein-1 signal path it triggers various different genes, among them several involved in neuroplastic remodelling.

Methods: We investigated the pattern of c-Fos expression in the anteroventral cochlear nucleus (AVCN) and the central inferior colliculus (CIC) following unilateral insertion of a cochlea implant (CI) into the medial turn or through the round window of the cochlea with continuous, electrical interacochlear stimulation (EIS) for 45 min to 5 h at 50 Hz in anaesthetized rats. The effectiveness of the stimulation was examined by measurement of the electrical auditory brainstem response.

Results: Following temporally varying EIS, tonotopic c-Fos expression was observed in the AVCN on the stimulated side. By counting c-Fos positive nuclei in the AVCN, we discovered spatiotemporal non-linearities, with high c-Fos densities after 2 and 5 h and a significant minimum after 3:15 h of EIS. In the central area of the AVCN, c-Fos density increases significantly from 2 to 5 h, while the adjacent lateral and medial regions remaining unchanged in nuclear density. As in AVCN, we observed a largely tonotopic c-Fos expression on the contralateral side of the CIC with a non-linear progression over various stimulation times (Figure 1 [Fig. 1]).

Conclusion: Under unilateral monotone CI-stimulation a non-linear development and a local differentiation of c-Fos positive neurons occur in the ipsilateral AVCN and the contralateral CIC. Apparently, sustained stimulation of the auditory system leads to a time-delayed neuroplastic remodeling of different neuronal subpopulations.


References

1.
Rosskothen N, Hirschmüller-Ohmes I, Illing RB. AP-1 activity rises by stimulation-dependent c-Fos expression in auditory neurons. NeuroReport. 2008; 19: 1091- 1093.
2.
Jakob T, Illing RB. Laterality, intensity, and frequency of electrical intracochlear stimulation are differentially mapped into specific patterns of gene expression in the rat auditory brainstem. Audiol. Med. 2008; 6: 215-227.
3.
Illing RB, Michler S, Laszig R. Transcription factor modulation and expression in the rat auditory brainstem following electrical intracochlear stimulation. Exp. Neurol. 2002; 175: 226-244.