Journal Article

Anterior olfactory nucleus mediates parallel inter-bulbar pathways in rodents

Wang, Li, Li, Anan, Guo, Jiajia, Yu, Feilong, Liu, Yue, Zhang, Zhijian, Liu, Qing, Xu, Fuqiang, Jia, Fan, Haddad, Rafi, Su, Peng, Jin, Sen

2025

Overview

Background Interhemispheric communication of olfactory information is crucial for accurate odor perception and odor source localization in animals. However, the underlying structural basis for this communication in mammals remains poorly understood. Using electrophysiological recordings and virus-mediated tracing, we systematically dissected the neural circuits involved in interhemispheric transmission between the bilateral olfactory bulbs (OBs). Results We identified the anterior olfactory nucleus (AON) as a central hub that facilitates direct communication between the OBs via three distinct pathways: the excitatory inter-bulbar pathway, the inhibitory inter-bulbar pathway, and the bi-bulbar co-innervation pathway. Notably, our results highlight the differential roles of AON subregions in these pathways: the pars externa (AONpE) primarily mediates the inhibitory pathway, while the pars principalis (AONpP) participates in all three pathways. These pathways recruit CaMKIIα-positive neurons in specific AON regions, which in turn project to distinct neuronal populations within the OBs.  Conclusions This study provides novel anatomical insights into the neural circuits underlying interhemispheric olfactory communication. The differential connectivity patterns of AON subregions contribute to a better understanding of how bilateral olfactory information is processed and transferred between the two OBs.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Animals / Anterior olfactory nucleus / Biomedical and Life Sciences / Brain research / Cerebral hemispheres / Chemical communication / Circuits / Communication / Electrophysiology / Information processing / Innervation / Interhemispheric communication / Interhemispheric transfer / Life Sciences / Localization / Male / Mice / Neural circuitry / Neural networks / Neurons / Odor / Odors / Olfactory bulb / Olfactory Bulb - anatomy & histology / Olfactory Bulb - physiology / Olfactory pathways / Olfactory Pathways - anatomy & histology / Olfactory Pathways - physiology / Physiological aspects / Post traumatic stress disorder / Rats / Rhinencephalon / Rodents / Smell - physiology / Tropical diseases / Virus tracing / Viruses