Katharina Jäger

(Doctoral Student )

Email: kajaeger@stud.uni-frankfurt.de
Phone: +49 69 / 798 42065 

Research project

The sensory cells in the cochlea, the inner and outer hair cells, are innervated by efferent fibers which originate in the superior olivary complex in the brainstem. The neurons of the superior olive in turn receive input from higher stages of the auditory pathway, including the auditory cortex. Indirect evidence indicates a modulating effect of efferent fibers coming from the cortex on the cochlea´s mode of operation. Until now, open questions remain about the cortex areas and layers, which are involved in these processes, as well as their neuromodulatory control.

In my PhD project I will investigate the influence of cortical activity on the mechanics in the inner ear by means of otoacoustic emission (OAE) measurements. OAEs are indicative of non-linear amplification processes of sound signals by outer hair cells. In the measurements I will influence neuronal cortex activity and thus the efferent feedback system via exciting electrical stimulation or application of inhibiting transmitter agonists. Possible amplitude and frequency changes in the simultaneously recorded OAEs could provide hints about the origin of the involved efferent control. The measurements are performed in the mongolian gerbil (Meriones unguiculatus), which is a suitable animal model for this purpose, as its hearing range extends into the low-frequency hearing range in humans.


Publications 2013
Jäger, A. and Kössl, M. (2013). Binaural Measurements of Otoacoustic Emissions in Humans. 36th Midwinter Meeting of the Association for Research in Otolaryngology, #1068.