Open AccessHierarchical organization of long‐range circuits in the olfactory cortices
Author(s) -
Yang Weiguo,
Sun QianQuan
Publication year - 2015
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12550
Subject(s) - piriform cortex , neuroscience , entorhinal cortex , sensory system , olfactory system , channelrhodopsin , glutamatergic , biological neural network , cortex (anatomy) , biology , optogenetics , central nervous system , hippocampus , glutamate receptor , biochemistry , receptor
How sensory information is processed within olfactory cortices is unclear. Here, we examined long‐range circuit wiring between different olfactory cortical regions of acute mouse brain slices using a channelrhodopsin‐2 (ChR2)‐based neuronal targeting approach. Our results provide detailed information regarding the synaptic properties of the reciprocal long‐range monosynaptic glutamatergic projections ( LRMGP ) between and within anterior piriform cortex ( aPC ), posterior piriform cortex ( pPC ), and lateral entorhinal cortex ( LEC ), thereby creating a long‐range inter‐ and intracortical circuit diagrams at the level of synapses and single cortical neurons. Our results reveal the following information regarding hierarchical intra‐ and intercortical organizations: (i) there is massive bottom‐up (i.e., rostral–caudal) excitation within the LRMGP accompanied with strong feedforward ( FF ) inhibition; (ii) there are convergent FF connections onto LEC from both aPC and pPC ; (iii) feedback ( FB ) intercortical connections are weak with a significant fraction of presumptive silent synapses; and (iv) intra and intercortical long‐range connections lack layer specificity and their innervation of interneurons are stronger than neighboring pyramidal neurons. The elucidation of the distinct hierarchical organization of long‐range olfactory cortical circuits paves the way for further understanding of higher order cortical processing within the olfactory system.