Fig. 2

Electrophysiological and molecular characterization of tPA expressing FS-PV interneurons. A,B Characterization of Plat-expressing FS-PV cells. A Current-clamp recordings of a Plat-expressing FS-PV interneuron. Upper traces show voltage responses to current steps (bottom traces). This neuron typically displayed a low input resistance, a high rheobasic current (120 pA, black trace first depolarizing current step) and fired short-duration action potentials with fast and large after hyperpolarizing potentials. A strong depolarizing current (380 pA) evoked a high and sustained firing rate with little or no spike frequency adaptation (shaded trace). B Agarose gel analysis of the RT-PCR products of the same FS-PV neuron showing expression of VGlut1, GAD65, GAD67, PV, Akr1c18, Sst, APC, Ncan, Plat, Ptprr, and Sema3a. C Ward’s clustering based on the expression of 16 genes performed on 28 cortical neurons (upper panel). The x-axis represents individual cells and the y-axis the average Euclidian within-cluster linkage distance. Pyramidal (grey) and FS-PV (magenta) cells were segregated into two first-order clusters as suggested by Thorndike procedure (dotted line). Gene expression profile of genes expression across the different cell clusters (bottom panel). For each cell, colored and white squares indicate presence and absence of genes, respectively. Note the presence of VGlut1 in pyramidal cells and of PV in FS-PV cells. Plat-expressing FS-PV neurons (dotted box) displayed a similar gene expression profile and were segregated together. D Histograms depicting a similar occurrence of Plat in pyramidal and FS-PV cells