Figure 1. | An inhibitory corticostriatal pathway

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An inhibitory corticostriatal pathway

Figure 1.

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University of Texas at San Antonio, United States
Figure 1.
Download figureOpen in new tabFigure 1. Morphological characteristics, axonal projections and electrical properties of long-range CS-SOM neurons in the mouse auditory cortex.

(a) Schematic depicting injection site using the SOM-Cre-tdTomato transgenic mouse line to identify CS-SOM neurons and their projections to the dorsal striatum. Bottom, auditory cortex: AAV.GFP.Flex injection site; yellow CS-SOM somata coexpressing GFP and tdTomato. Top, dorsal striatum: green CS-SOM GFP-positive axons; red SOM tdTomato-positive interneurons. (b) Epifluorescence images of SOM GFP-positive neurons. Top, left: GFP-positive SOM neurons in the auditory cortex identified by viral injection of AAV.GFP.Flex in the SOM-Cre-tdTomato transgenic mouse line. Middle, left: tdTomato-expressing SOM neurons in the SOM-Cre-tdTomato transgenic mouse line. Bottom, left: overlay of GFP and tdTomato images. Middle, the dashed box indicates the location GFP-positive axons from CS-SOM neurons in the dorsal striatum and the location of image in the right panel. Right, higher magnification of GFP fluorescence of CS-SOM axons in the dorsal striatum. (c) Schematic depicting injection site using the SOM-Cre transgenic mouse line to identify CS-SOM neurons by anatomical retrograde transfection. Top, striatum: AAV.GFP.Flex injection site. Bottom, auditory cortex: green CS-SOM GFP positive somata. (d) Bright-field (top left) and epifluorescence (bottom left) images of striatal SOM interneurons transfected with AAV.GFP.Flex. Middle (left and right), epifluorescence image of laminar distribution of CS-SOM neurons in the auditory cortex identified by anatomical retrograde transfection. Right, high-resolution image of a biocytin-labeled CS-SOM neuron. (e) Morphological reconstruction of one CS-SOM neuron (dendrites, blue; axons, gray). (f) Bottom, train of action potentials recorded in a GFP-positive CS-SOM neuron during step current injection (1.0 s, 100 pA pulse). Top, single action potential from GFP-positive CS-SOM neuron (black); compare to an action potential from a fast-spiking interneuron (red). (g) Summary plot of Vrest: resting membrane potential; Ri: input resistance; Tau: membrane time constant; Rheobase, the smallest current step evoking an action potential; AP thr: action potential threshold; AP height: action potential height; AP half-width: action potential half-width; and F/I slope from CS-SOM neurons (n = 13), including group averages (± s.e.m.).

DOI: http://dx.doi.org/10.7554/eLife.15890.003