title: The columnar and laminar organization of inhibitory connections to neocortical excitatory cells.
abstract: The cytoarchitectonic similarities of different neocortical regions have given rise to the idea of 'canonical' connectivity between excitatory neurons of different layers within a column. It is unclear whether similarly general organizational principles also exist for inhibitory neocortical circuits. Here we delineate and compare local inhibitory-to-excitatory wiring patterns in all principal layers of primary motor (M1), somatosensory (S1) and visual (V1) cortex, using genetically targeted photostimulation in a mouse knock-in line that conditionally expresses channelrhodopsin-2 in GABAergic neurons. Inhibitory inputs to excitatory neurons derived largely from the same cortical layer within a three-column diameter. However, subsets of pyramidal cells in layers 2/3 and 5B received extensive translaminar inhibition. These neurons were prominent in V1, where they might correspond to complex cells, less numerous in barrel cortex and absent in M1. Although inhibitory connection patterns were stereotypical, the abundance of individual motifs varied between regions and cells, potentially reflecting functional specializations.
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
authors.forename: Dennis
authors.initials: D
authors.lastname: Kätzel
authors.forename: Boris V
authors.initials: BV
authors.lastname: Zemelman
authors.forename: Christina
authors.initials: C
authors.lastname: Buetfering
authors.forename: Markus
authors.initials: M
authors.lastname: Wölfel
authors.forename: Gero
authors.initials: G
authors.lastname: Miesenböck
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D000075402:Channelrhodopsins; D055879:Gene Knock-In Techniques; D007395:Interneurons / Q000378:metabolism / Q000502:physiology; D051379:Mice; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology; D019579:Neocortex / Q000033:anatomy & histology* / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D009434:Neural Pathways / Q000033:anatomy & histology* / Q000502:physiology; D056347:Neuroanatomical Tract-Tracing Techniques / Q000379:methods; D009474:Neurons / Q000502:physiology; D010775:Photic Stimulation; D013003:Somatosensory Cortex / Q000033:anatomy & histology / Q000502:physiology; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D000075402:Channelrhodopsins; D005680:gamma-Aminobutyric Acid