title: Complementary sensory and associative microcircuitry in primary olfactory cortex.
abstract: The three-layered primary olfactory (piriform) cortex is the largest component of the olfactory cortex. Sensory and intracortical inputs converge on principal cells in the anterior piriform cortex (aPC). We characterize organization principles of the sensory and intracortical microcircuitry of layer II and III principal cells in acute slices of rat aPC using laser-scanning photostimulation and fast two-photon population Ca(2+) imaging. Layer II and III principal cells are set up on a superficial-to-deep vertical axis. We found that the position on this axis correlates with input resistance and bursting behavior. These parameters scale with distinct patterns of incorporation into sensory and associative microcircuits, resulting in a converse gradient of sensory and intracortical inputs. In layer II, sensory circuits dominate superficial cells, whereas incorporation in intracortical circuits increases with depth. Layer III pyramidal cells receive more intracortical inputs than layer II pyramidal cells, but with an asymmetric dorsal offset. This microcircuit organization results in a diverse hybrid feedforward/recurrent network of neurons integrating varying ratios of intracortical and sensory input depending on a cell's position on the superficial-to-deep vertical axis. Since burstiness of spiking correlates with both the cell's location on this axis and its incorporation in intracortical microcircuitry, the neuronal output mode may encode a given cell's involvement in sensory versus associative processing.
authors.affiliation: Neuroscience Research Center, and Department of Psychiatry, Charité-Universtiätsmedizin Berlin, 10117 Berlin, Germany.
authors.forename: Hauke F
authors.initials: HF
authors.lastname: Wiegand
authors.forename: Prateep
authors.initials: P
authors.lastname: Beed
authors.forename: Michael H K
authors.initials: MH
authors.lastname: Bendels
authors.forename: Christian
authors.initials: C
authors.lastname: Leibold
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schmitz
authors.forename: Friedrich W
authors.initials: FW
authors.lastname: Johenning
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000344:Afferent Pathways / Q000166:cytology / Q000502:physiology; D000818:Animals; D001931:Brain Mapping / Q000379:methods; D002118:Calcium / Q000502:physiology; D005260:Female; D018698:Glutamic Acid / Q000502:physiology; D008297:Male; D009833:Olfactory Pathways / Q000166:cytology* / Q000502:physiology*; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques / Q000379:methods; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011984:Sensory Receptor Cells / Q000502:physiology*
chemical_list: D018698:Glutamic Acid; D002118:Calcium