The organization and development of cortical interneuron presynaptic circuits are area specific

• Published in: Cell reports (Cambridge) 2021-11, Vol.37 (6), p.109993-109993, Article 109993
• Main Authors: Pouchelon, Gabrielle, Dwivedi, Deepanjali, Bollmann, Yannick, Agba, Chimuanya K., Xu, Qing, Mirow, Andrea M.C., Kim, Sehyun, Qiu, Yanjie, Sevier, Elaine, Ritola, Kimberly D., Cossart, Rosa, Fishell, Gord
• Format: Article
• Language: English
• Subjects: ALM; Animals; Cerebral Cortex - metabolism; Cerebral Cortex - pathology; cortical areas; development; Female; Fragile X Mental Retardation Protein - physiology; fragile X syndrome; Fragile X Syndrome - genetics; Fragile X Syndrome - metabolism; Fragile X Syndrome - pathology; GABAergic interneurons; Interneurons - metabolism; Interneurons - pathology; Life Sciences; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; monosynaptic rabies tracing; Neural Pathways; Presynaptic Terminals - metabolism; Presynaptic Terminals - pathology; Rabies virus - genetics; Sense Organs - metabolism; Sense Organs - pathology; sensory cortex; Synapses - metabolism; Synapses - pathology; thalamocortical input
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2021.109993

Parvalbumin and somatostatin inhibitory interneurons gate information flow in discrete cortical areas that compute sensory and cognitive functions. Despite the considerable differences between areas, individual interneuron subtypes are genetically invariant and are thought to form canonical circuits regardless of which area they are embedded in. Here, we investigate whether this is achieved through selective and systematic variations in their afferent connectivity during development. To this end, we examined the development of their inputs within distinct cortical areas. We find that interneuron afferents show little evidence of being globally stereotyped. Rather, each subtype displays characteristic regional connectivity and distinct developmental dynamics by which this connectivity is achieved. Moreover, afferents dynamically regulated during development are disrupted by early sensory deprivation and in a model of fragile X syndrome. These data provide a comprehensive map of interneuron afferents across cortical areas and reveal the logic by which these circuits are established during development. [Display omitted] •Monosynaptic rabies tracing and physiological properties reveal circuit maturation•Inputs to inhibitory interneurons are primarily defined by their cortical location•Cell types adjust their areal-specific inputs with distinct developmental dynamics•Fmr1 KO and sensory deprivations induce specific sets of input maturation defects Using monosynaptic rabies tracing and physiology, Pouchelon et al. show that inputs to inhibitory interneurons primarily reflect their cortical location, which adjust those inputs through distinct dynamics during development, in accordance with cell type. Specific sets of the developmentally regulated inputs are disrupted by sensory deprivation or in Fmr1 KOs.