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. Author manuscript; available in PMC: 2019 Feb 27.
Published in final edited form as: Nat Neurosci. 2018 Aug 27;21(9):1185–1195. doi: 10.1038/s41593-018-0205-2

Figure 4. Intrinsic electrophysiological properties of rosehip cells.

Figure 4

A, Examples of different firing patterns induced by current injections in layer 1 interneurons. Firing pattern of a RC (top), a NGFC (middle) and an unidentified layer 1 interneuron (bottom). B, Support vector machine (SVM) based wrapper feature selection of electrophysiological parameters for the identification of RCs. Anatomically identified RCs (red dots) and other types of interneurons with known morphology (black dots) are mapped to the distribution of electrophysiological features ranked as the two best delineators by SVM. Black lines show the best hyperplane separating RCs from other interneuron types. C-D, RCs exhibit distinct impedance profile relative to neurogliaform and other human interneurons in layer 1. C, Individual responses of anatomically identified rosehip (red), neurogliaform (blue) and other (black) interneurons to current injections with an exponential chirp (0.2-200 Hz, top). Traces were normalized to the amplitude of the rosehip response at 200 Hz. D, Left, Normalized impedance (Z) profiles of distinct groups of interneurons. RCs (n=5) had higher impedance in the range of 0.9 - 12.4 Hz compared to neurogliaform (n=5) and other (n=5) interneurons. Shaded regions represent standard deviation. Right, Impedances were similar at the lowest frequency (Z0.2 Hz, left), but resonance magnitude (Q) calculated as maximal impedance value divided by the impedance at lowest frequency (middle) and frequencies of maximal impedance (fmax, right) showed significant differences (p<0.05, ANOVA with and Bonferroni post hoc correction). E, Automatized selection of recording periods for the assessment of subthreshold membrane potential oscillations (boxed segments) and detection of bursts (bars) for measuring intraburst spiking frequency demonstrated on a RC response to near rheobasic stimulation showing stuttering firing behavior. F, Averaged fast Fourier transforms (FFT) of membrane potential oscillations had higher power between 3.8 and 80 Hz in RCs compared to neurogliaform and other interneurons. G, Intraburst frequency of RCs peaked in the gamma range.