Josef Bischofberger: GABAergic signaling in newborn granule cells of the adult hippocampus
| When |
Mar 08, 2022
from 05:15 PM to 06:00 PM |
|---|---|
| Where | Zoom Meeting. Meeting ID and password will be sent with the e-mail invitation. You can also contact Fiona Siegfried for meeting ID and password. |
| Contact Name | Fiona Siegfried |
| Contact Phone | 0761 203 9549 |
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Abstract
GABA depolarize immature neurons close to the action potential (AP) threshold in development and adult neurogenesis. Nevertheless, GABAergic synapses effectively inhibit AP firing in newborn granule cells of the adult hippocampus. To investigate the underlying mechanisms, we have analyzed GABAergic inputs from soma-targeting parvalbumin and dendrite-targeting somatostatin interneurons.
Surprisingly, both interneuron subtypes activate α5-subunit containing GABAA receptors (α5-GABAARs) in young neurons, showing a nonlinear voltage-dependent activation with large conductance around the AP threshold. By contrast, in mature cells, parvalbumin interneuron synapses lack α5-subunits, while somatostatin interneurons continue to target nonlinear α5-GABAARs. Computational modelling shows that the voltage-dependent amplification of α5-GABAAR opening in young neurons is crucial for inhibition of AP firing to generate balanced and sparse firing activity, even with depolarized GABA reversal potential.