Egger, Veronica and Kuner, Thomas (2021) Olfactory bulb granule cells: specialized to link coactive glomerular columns for percept generation and discrimination of odors. CELL AND TISSUE RESEARCH, 383 (1). pp. 495-506. ISSN 0302-766X, 1432-0878
Full text not available from this repository. (Request a copy)Abstract
The role of granule cells in olfactory processing is surrounded by several enigmatic observations, such as the purpose of reciprocal spines and the mechanisms for GABA release, the apparently low firing activity and recurrent inhibitory drive of granule cells, the missing proof for functional reciprocal connectivity, and the apparently negligible contribution to lateral inhibition. Here, we summarize recent results with regard to both the mechanisms of GABA release and the behavioral relevance of granule cell activity during odor discrimination. We outline a novel hypothesis that has the potential to resolve most of these enigmas and allows further predictions on the function of granule cells in odor processing. Briefly, recent findings imply that GABA release from the reciprocal spine requires a local spine action potential and the cooperative action of NMDA receptors and high voltage-activated Ca2+ channels. Thus, lateral inhibition is conditional on activity in the principal neurons connected to a granule cell and tightly intertwined with recurrent inhibition. This notion allows us to infer that lateral inhibition between principal neurons occurs "on demand," i.e., selectively on coactive mitral and tufted cells, and thus can provide directed, dynamically switched lateral inhibition in a sensory system with 1000 input channels organized in glomerular columns. The mechanistic underpinnings of this hypothesis concur with findings from odor discrimination behavior in mice with synaptic proteins deleted in granule cells. In summary, our hypothesis explains the unusual microcircuit of the granule cell reciprocal spine as a means of olfactory combinatorial coding.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | NMDA RECEPTORS; MITRAL CELLS; GABA RELEASE; DENDRODENDRITIC SYNAPSES; FEEDFORWARD INHIBITION; SYNAPTIC INHIBITION; LATERAL INHIBITION; CALCIUM INFLUX; TUFTED CELLS; REPRESENTATIONS; GABA; Granule cells; Olfactory processing |
| Subjects: | 500 Science > 590 Zoological sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Zoologie > Neurophysiologie (Prof. Dr. Veronica Egger) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 05 Sep 2022 06:12 |
| Last Modified: | 05 Sep 2022 06:12 |
| URI: | https://pred.uni-regensburg.de/id/eprint/46530 |
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