Skip to main content
. Author manuscript; available in PMC: 2023 Sep 21.
Published in final edited form as: Neuron. 2022 Aug 8;110(18):3036–3052.e5. doi: 10.1016/j.neuron.2022.07.004

Figure 4: Input and output synaptic connections of fear learning-activated somatostatin interneurons exhibit distinct properties.

Figure 4:

(A) Targeting of activated (eYFP+/ tdTomato+) versus nonactivated SST-INs (eYFP−/ tdTomato+) for electrophysiology following CS-US pairing. (B) Boxplots depict spontaneous EPSC parameters from tagged (n = 15 cells) and non-tagged SST-INs (n = 15 cells) in the same slices (n = 6 slices from 5 mice). Interevent interval: U = 205, p = 1.35 × 10−4, Mann-Whitney U-test. Amplitude: t28 = −1.03, p = 0.31, two-sided unpaired t-test. (C) Boxplots depict spontaneous IPSC parameters from tagged (n = 14 cells) and non-tagged SST-INs (n = 14 cells) in the same slices (n = 6 slices from 5 mice). Interevent interval: U = 89, p = 0.696, Mann-Whitney U-test. Amplitude: t26 = 0.945, p = 0.353, Mann-Whitney U-test. (D) Boxplots depict EPSC amplitude from tagged (n = 10 cells) and non-tagged SST-INs (n = 11 cells) in the same slices (n = 4 slices in 3 mice) during paired pulse stimulation. Paired pulse ratio: F(3,7) = 16.6, p = 0.0014, interaction between cell type and delay, 2-way repeated measures ANOVA. (E) Electrophysiological analysis of connections from tagged SST-INs onto PV-INs (tdTomato+) as well as tagged (tdTomato+) and non-tagged PNs (tdTomato-) following CS-US pairing or unpaired conditioning. (F) Example IPSCs. (G) Boxplots depict amplitude of IPSCs resulting from photoexcitation (460 nm, 1 ms, 0.1 Hz) of tagged SST-INs in PV-INs, non-tagged PNs (NT-PNs), and tagged PNs (T-PNs) following unpaired conditioning (n = 3 slices from 3 mice: PV-INs (n = 10 cells), NT-PNs (n = 10 cells), T-PNs (n = 8 cells)) and CS-US pairing (n = 3 slices from 3 mice: PV-INs (n = 9 cells), NT-PNs (n = 14 cells), T-PNs (n = 12 cells)). Unpaired conditioning: χ2 = 13.0 (2), p = 0.0015, Kruskal-Wallis ANOVA. CS-US pairing: χ2 = 17.8 (2), p = 1.32 × 10−4, Kruskal-Wallis ANOVA. (H) Boxplots depict amplitude of IPSCs from PV-INs and tagged PNs normalized to the median amplitude of non-tagged PNs from the same slices. PV-IN amplitude: t4 = 3.56, p = 0.023, two-sided unpaired t-test. Tagged PN amplitude: t4 = 4.19, p = 0.013, two-sided unpaired t-test. (I) Model of relative output strength of SST-INs in unpaired versus paired mice. * p < 0.05, ** p < 0.01, *** p < 0.001 by Mann Whitney U-test (B), Tukey’s post-hoc test (D), unpaired t-test (H) or Dunn’s post-hoc test (G). See also Figure S6.