Physiological Properties of Supragranular Cortical Inhibitory Interneurons Expressing Retrograde Persistent Firing

Figure 4

Persistent firing layer 2/3 interneurons showed small soma size and heterologous gap junction coupling. (a) One representative biocytin-filled FS-nPF and nFS-nPF interneuron (top) and two representative biocytin-filled nFS-PF interneurons (bottom). (b) Size of soma in the three electrophysiologically characterized interneuronal classes (FS nonpersistent firing, FS-nPF; nFS nonpersistent firing, nFS-nPF; nFS persistent firing, nFS-PF). (c) Triple immunofluorescence staining for biocytin (red), GFP (green), and parvalbumin (blue). The white arrow points at one representative biocytin-filled nFS-PF neuron. Note the biocytin diffusion from the patched-PF interneuron (white arrow) into two neighboring GFP and parvalbumin-positive interneurons (presumably FS-nPF) (grey arrow heads), suggesting gap junction coupling among these cells.

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