Bulbar projecting subcortical GABAergic neurons send collateral branches extensively and selectively to primary olfactory cortical regions.
J Comp Neurol
; 531(3): 451-460, 2023 02.
Article
en En
| MEDLINE
| ID: mdl-36463397
Circuit operations of the olfactory bulb are modulated by higher order projections from multiple regions, many of which are themselves targets of bulbar output. Multiple glutamatergic regions project to the olfactory bulb, including the anterior olfactory nucleus (AON), prefrontal cortex (PFC), piriform cortex (PC), entorhinal cortex (EC), and tenia tecta (TT). In contrast, only one region provides GABAergic projections to the bulb. These GABA neurons are located in the horizontal limb of the diagonal band of Broca extending posteriorly through the magnocellular preoptic nucleus to the nucleus of the lateral olfactory bulb. However, it was unclear whether bulbar projecting GABAergic neurons collaterallize projecting to other brain regions. To address this, we mapped collateral projections from bulbar projecting GABAergic neurons using intersectional strategies of viral and traditional tract tracers. This approach revealed bulbar projecting GABAergic neurons show remarkable specificity targeting other primary olfactory cortical regions exhibiting abundant collateral projections into the accessory olfactory bulb, AON, PFC, PC, and TT. The only "nonolfactory" region receiving collateral projections was sparse connectivity to the medial prefrontal orbital cortex. This suggests that basal forebrain inhibitory feedback also modulates glutamatergic feedback areas that are themselves prominent bulbar projection regions. Thus, inhibitory feedback may be simultaneously modulating both synaptic processing of olfactory information in the bulb and associational processing of olfactory information from primary olfactory cortex. We hypothesize that these olfactory GABAergic feedback neurons are a regulator of the entire olfactory system.
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Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Bulbo Olfatorio
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Encéfalo
Idioma:
En
Revista:
J Comp Neurol
Año:
2023
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos