Inhibitory interneurons represent 10-15% of the neurons in the somatosensory cortex, and their activity powerfully shapes sensory processing. Three major groups of GABAergic interneurons have been defined according to developmental, molecular, morphological, electrophysiological, and synaptic features. Dendritic-targeting somatostatin-expressing interneurons (SST-INs) have been shown to display diverse morphological, electrophysiological, and molecular properties and activity patterns in vivo However, the correlation between these properties and SST-IN subtype is unclear. In this study, we aimed to correlate the morphological diversity of layer 5 (L5) SST-INs with their electrophysiological and molecular diversity in mice of either sex. Our morphological analysis demonstrated the existence of three subtypes of L5 SST-INs with distinct electrophysiological properties: T-shaped Martinotti cells innervate L1, and are low-threshold spiking; fanning-out Martinotti cells innervate L2/3 and the lower half of L1, and show adapting firing patterns; non-Martinotti cells innervate L4, and show a quasi-fast spiking firing pattern. We estimated the proportion of each subtype in L5 and found that T-shaped Martinotti, fanning-out Martinotti, and Non-Martinotti cells represent ∼10, ∼50, and ∼40% of L5 SST-INs, respectively. Last, we examined the connectivity between the three SST-IN subtypes and L5 pyramidal cells (PCs). We found that L5 T-shaped Martinotti cells inhibit the L1 apical tuft of nearby PCs; L5 fanning-out Martinotti cells also inhibit nearby PCs but they target the dendrite mainly in L2/3. On the other hand, non-Martinotti cells inhibit the dendrites of L4 neurons while avoiding L5 PCs. Our data suggest that morphologically distinct SST-INs gate different excitatory inputs in the barrel cortex.SIGNIFICANCE STATEMENT Morphologically diverse layer 5 SST-INs show different patterns of activity in behaving animals. However, little is known about the abundance and connectivity of each morphological type and the correlation between morphological subtype and spiking properties. We demonstrate a correlation between the morphological and electrophysiological diversity of layer 5 SST-INs. Based on these findings we built a classifier to infer the abundance of each morphological subtype. Last, using paired recordings combined with morphological analysis, we investigated the connectivity of each morphological subtype. Our data suggest that, by targeting different cell types and cellular compartments, morphologically diverse SST-INs might gate different excitatory inputs in the mouse barrel cortex.
Pubmed ID: 29326172 RIS Download
Publication data is provided by the National Library of Medicine ® and PubMed ®. Data is retrieved from PubMed ® on a weekly schedule. For terms and conditions see the National Library of Medicine Terms and Conditions.
This polyclonal targets GFP
View all literature mentionsThis monoclonal targets Calbindin D-28k
View all literature mentionsThis polyclonal targets Calbindin D-28k
View all literature mentionsThis unknown targets Somatostatin-14
View all literature mentionsMulti paradigm numerical computing environment and fourth generation programming language developed by MathWorks. Allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, Java, Fortran and Python. Used to explore and visualize ideas and collaborate across disciplines including signal and image processing, communications, control systems, and computational finance.
View all literature mentionsA complete graphing and data analysis software package that provides a suite of features catering to the needs of scientists and engineers. Main features: * Drag-and-drop import of data and images * Save import settings to a worksheet or external files for repeated use * Use saved settings to re-import files with a single click * Post-process imported data * Import Wizard with visual feedback * Handle non-standard files by programming
View all literature mentionsSoftware suite for electrophysiology data acquisition and analysis by Molecular Devices. Used for the control and recording of voltage clamp, current clamp, and patch clamp experiments. The software suite consists of Clampex 11 Software for data acquisition, AxoScope 11 Software for background recording, Clampfit 11 Software for data analysis, and optional Clampfit Advanced Analysis Module for sophisticated and streamlined analysis.
View all literature mentionsMus musculus with name B6;129S-Gt(ROSA)26Sortm65.1(CAG-tdTomato)Hze/J from IMSR.
View all literature mentionsMus musculus with name B6;129S-Calb1tm2.1(cre)Hze/J from IMSR.
View all literature mentionsMus musculus with name B6(Cg)-Calb2tm1(cre)Zjh/J from IMSR.
View all literature mentionsMus musculus with name STOCK Ssttm3.1(flpo)Zjh/J from IMSR.
View all literature mentionsMus musculus with name B6.129X1-Gt(ROSA)26Sortm1(EYFP)Cos/J from IMSR.
View all literature mentionsMus musculus with name B6.Cg-Gt(ROSA)26Sortm9(CAG-tdTomato)Hze/J from IMSR.
View all literature mentionsMus musculus with name B6J.Cg-Ssttm2.1(cre)Zjh/MwarJ from IMSR.
View all literature mentions