Event Abstract Back to Event The Selective requirement of Activity in maturation of specific cortical interneuron populations. N. DeMarco1*, Fishell G1 and Karayannis T1 1 NYU Langone Medical Center, Smilow Neuroscience Program and the Departments of Cell Biology and Neural Science, United States Recent experimental evidence uncovered the identity of genetic programs that regulate the generation of GABAergic interneuron subtypes. In contrast, the notion that spontaneous neuronal activity may contribute to interneuron differentiation remains unexplored. Caudal ganglionic eminence (CGE)-derived interneurons are born relatively late during embryonic development in the ventral telencephalon and migrate dorsally to reach stereotypic positions in cortical laminae. Different patterns of early neuronal activity can be detected in migrating interneurons and after they reach their laminar destination. However, the significance of early activity for subtype maturation is not understood. We sought to assess the role of activity in the maturation of CGE-interneuron subtypes. To manipulate the excitability of developing interneurons, we targeted the expression of the inward rectifying potassium channel Kir2.1 to CGE-derived interneurons. We overexpress the channel under the Dlx5/6 enhancer element by means of in utero electroporation. The high levels of GFP expression achieved with this approach allowed for the detailed characterization of neuronal morphologies. Our experiments revealed that calretinin (Cr) and reelin (Re)-expressing CGE-derived interneurons exhibit marked defects in axonal arborization. In addition, Re interneurons show simple dendritic arbors and a concomitant defect in the kinetics of excitatory synaptic inputs. In contrast, vasointestinal peptide (VIP)-expressing interneurons are not affected by changes in membrane excitability. In addition, Cr and Re interneurons fail to migrate to appropriate laminae and occupy deeper layers in the somatosensory cortex. By using a suppressible genetic strategy, we found that neuronal activity is required cell-autonomously and independently at different developmental stages to determine neuronal morphology and layer positioning of select CGE-derived interneuron subtypes. Cr and Re interneuron silencing between postnatal day 2 (P2) and P3 perturbs laminar targeting whereas the development of neuronal morphology is unaffected. In contrast, reduction in neuronal excitability after P3 impairs the proper development of axons and dendrites. Blockade of synaptic transmission has no effect on either migration or morphology suggesting that the cell-autonomous release of GABA is not required for subtype specification. By contrast, we observed that pharmacological suppression of glutamatergic transmission phenocopied the morphological defects observed in Cr ant Re-expressing interneuron populations. We conclude that in these populations activity is sequentially required for the selection of laminar position and differentiation of select populations of cortical interneurons. Conference: EMBO workshop: Gaba Signalling and Brain Networks , Amsterdam, Netherlands, 30 Jun - 2 Jul, 2010. Presentation Type: Oral Presentation Topic: Talks Citation: DeMarco N, G F and T K (2010). The Selective requirement of Activity in maturation of specific cortical interneuron populations.. Conference Abstract: EMBO workshop: Gaba Signalling and Brain Networks . doi: 10.3389/conf.fnins.2010.15.00030 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Jun 2010; Published Online: 22 Jun 2010. * Correspondence: N. DeMarco, NYU Langone Medical Center, Smilow Neuroscience Program and the Departments of Cell Biology and Neural Science, New York, United States, gordon.fishell@med.nyu.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers N. DeMarco Fishell G Karayannis T Google N. DeMarco Fishell G Karayannis T Google Scholar N. DeMarco Fishell G Karayannis T PubMed N. DeMarco Fishell G Karayannis T Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.