Development of acoustically evoked and spontaneous pre- and postsynaptic discharge activity in the anteroventral cochlear nucleus (AVCN) and in the medial nucleus of the trapezoid body (MNTB): An melectrophysiological in vivo study in mice and Mongolian gerbils. (DASDA)
Final Report Abstract
The present project uses in vivo and in vitro electrophysiology and employs complex acoustic stimulation as well as electrical stimulation to get a better understanding of the role of systemic inhibition and of purinergic signaling on signal processing in the auditory brainstem. To place the planned studies on reliable footing it was necessary to conduct a new physiological classification of the neurons of the ventral cochlear nucleus, which is the starting point of several afferent processing pathways. The results provide evidence that neuronal inhibition effectively modulates the activity of bushy cells in the ventral cochlear nucleus, while in the MNTB acoustically evoked inhibition (if at all) only plays a subliminal role in sculpting discharge activity. Purinergic signaling has a significant effect during the early postnatal developmental period A second aspect, that received more and more attention while working on the project, was the change in spontaneous and stimulus evoked neuronal discharges before and after the onset of acoustically evoked discharge activity. The investigation of this new aspect was already started towards the end of the previous funding period. This aspect had to be considered, since excitation and inhibition undergoes strong developmental changes and thus it was crucial to get a better understanding of the brainstem activity in animals before the onset of acoustically evoked central nervous signal processing. The respective studies stimulated a cooperation with the lab of Karl Kandler in Pittsburg (USA) in which it could be demonstrated that the temporal structure of the afferent activity conveys information for the fine wiring of auditory brainstem circuits.
Publications
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(2009) Development of spontaneous and acoustically evoked discharge activity in vivo of MNTB principal cells in mice before and after hearing onset. J. Neuroscience 29:9510–9520
Sonntag, M., Englitz, B., Kopp-Scheinpflug, C., Rübsamen, R.
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(2011) The Calyx of Held Develops Adult-like Dynamics and Reliability by Hearing Onset in the Mouse in vivo. J. Neurosci. 31:6699-6709
Sonntag, M., Englitz, B., Typlt, M., Rübsamen, R.
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(2012) Multidimensional characterization and differentiation of neurons in the anteroventral cochlear nucleus. PLOS One 7(1): e29965
Typlt, M., Englitz, B., Sonntag, M., Dehmel, S., Kopp-Scheinpflug, C., Rübsamen, R.
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(2012) Purinergic modulation of neuronal activity in developing auditory brainstem. J. Neuroscience 32(31):10699 –10712
Dietz B, Jovanovic S, Wielsch B, Nerlich, J., Rübsamen R, Milenkovic I.
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(2014) Depolarizing chloride gradient in developing cochlear nucleus neurons: Underlying mechanism and implication for calcium signaling. Neurocience 261:207-222
Witte, M., Reinert, T., Dietz, B., Nerlich, J., Rübsamen, R., Milenkovic, I.
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(2014) Dynamic fidelity control to the central auditory system: Synergistic glycine/GABAergic inhibition in the cochlear nucleus. J. Neuroscience 34:11604-20
Jana Nerlich, Thomas Kuenzel, Christian Keine, Andrej Korenic, Rudolf Rübsamen, Ivan Milenkovic
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(2014). The precise temporal pattern of prehearing spontaneous activity is necessary for tonotopic map refinement. Neuron 82, 822–835
Clause, A., Kim, G., Sonntag, M., Vetter, D.E., Rübsamen, R., Kandler, K.
