Didier De Saint Jan1
"1 Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique Strasbourg, France,
Didier De Saint Jan: [email protected]"
"The olfactory bulb (OB), the first relay for odor processing in the brain, receives dense GABAergic and cholinergic long-range projections from basal forebrain (BF) nuclei that provide information about the internal state and behavioral context of the animal. However, the targets, impact, and dynamic of these afferents are still unclear. How BF synaptic inputs modulate activity in diverse subtypes of periglomerular (PG) interneurons using optogenetic stimulation and loose cell-attached or whole-cell patch-clamp recording in OB slices from adult mice were studied in this article. GABAergic BF inputs potently blocked PG cells firing except in a minority of calretinin-expressing cells in which GABA release elicited spiking. Parallel cholinergic projections excited a previously overlooked PG cell subtype via synaptic activation of M1 muscarinic receptors. Low-frequency stimulation of the cholinergic axons drove persistent firing in these PG cells, thereby increasing tonic inhibition in principal neurons. Taken together, these findings suggest that modality-specific BF inputs can orchestrate synaptic inhibition in OB glomeruli using multiple, potentially independent, inhibitory or excitatory target-specific pathways.
Research organism: Mouse
DOI: https://dx.doi.org/ 10.7554/eLife.71965
Optical stimulation of the BF axons was done using a blue LED (490 nm, pE 100, CoolLED Ltd., Andover, UK) directed through the ×40 objective of the microscope at 50–100% of its maximum power (5 mW at the objective output) and driven by the AxoGraph X acquisition software (AxoGraph Scientific).
Product Associated Features
The compact, single-bandwidth pE-100 is ideal for visualising a single fluorophore - in this case tdT to identify dopaminergic neurons.
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