Felix Felmy: Species-specific physiological and structural adaptations of MNTB principal neurons
| When |
Dec 14, 2022
from 12:15 PM to 01:00 PM |
|---|---|
| Where | Bernstein Center, Hansastr. 9a, Lecture Hall. Hybrid Format via Zoom. Meeting ID and password will be sent with e-mail invitation. You can also contact Fiona Siegfried for Meeting ID and password. |
| Contact Name | Fiona Siegfried |
| Add event to calendar |
 vCal iCal
|
Abstract
Within the auditory brainstem pathways, the medial nucleus of the trapezoid body (MNTB) represents an evolutionarily conserved structure that is present in all mammals investigated so far. The anatomical hallmark of MNTB neurons is a large somatic synapse, the calyx of Held, which generates one-to-one information transfer. Functionally, the MNTB is involved in binaural hearing and gap detection by generating a rapid and temporally precise feed-forward inhibition to local and distal auditory structures. The morphometry of the postsynaptic principle neurons is largely unexplored. Following from the proposed functional similarity, MNTB neuron morphology and physiology are supposed to be species invariant.
We compared the structure of individual MNTB neurons across five mammalian species and the gross anatomy in a total of eight species. We find that neither brain size nor phylogenetic distance is the exclusive determinant of cell size or arrangement as well as dendritic or axonal morphometry. However, significant species-dependent differences in most morphological features are present. In all species tested, in addition to the large somatic calyx of Held synapse, dendrites and axons are targeted by excitatory and inhibitory inputs.
The functional comparison of bat and gerbil MNTB neurons indicated again species-dependent differences in synaptic and biophysical features. These differences allow bats to outperform gerbils in temporal precision and faithfulness at high stimulation frequencies. Thus, investigations of single species do not yield a blue print even for evolutionarily conserved circuits as species-specific adaptations prevail, which underlines the importance for comparative research to differentiate general circuit functions and their species-specific adaptations.
