Fig. 5: PKCδ/CEloff neuronal activity during CS exposure is required for extinction memory formation.
From: Central amygdala micro-circuits mediate fear extinction
a Left, PKCδ unit identified with optogenetics. Right, waveform similarity of spikes with or without optogenetic stimulation. Bottom right, latency and magnitude of inhibition of PKCδ/CEloff neurons. b Normalized activity (z-score, bottom) of PKCδ/CEloff cells (n = 7) and example raster plot (top). CS: conditioned stimuli. c An adeno-associated virus (AAV2/7) conditionally expressing ChR2, eNpHR and a Venus reporter under the control of an elongation factor-1α (EF-1α) promoter was injected into the CEl of a PKCδ-Cre+ or PKCδ-Cre− mice (middle). Anti-GFP immunolabelling of the Venus reporter gene in CEl (right). DIO: double-inverted open reading frame; PKCδ: protein-kinase c delta; 2A: ribosomal self-processing peptide; BLA: basolateral amygdala; CEA: central amygdala. d Behavioural protocol. e Freezing response in PKCδ-Cre+ mice expressing ChR2 and eNpHR in PKCδ neurons. B6 mice: n = 11; freezing, ChR2, fear memory, CS I: 65.5 ± 5.6%, extinction learning, CS I: 57.1 ± 4.5%, CS II: 39.9 ± 5.2%, CS III: 37.9 ± 7.3%, CS IV: 33.7 ± 7.0%, extinction memory, CS I: 37.7 ± 5.0. eNpHR, fear memory, CS I: 59.9 ± 6.3%, extinction learning, CS I: 60.1 ± 8.4%, CS II: 42.4 ± 7.3%, CS III: 44.9 ± 7.4%, CS IV: 40.5 ± 8.2%, extinction memory, CS I: 60.1 ± 5.2% (blocks of 4 CSs). Main effect of CS presentations during extinction learning: two-way repeated-measures ANOVA F(5,49) = 8.7, p < 0.001. Interaction of light stimulation and CS presentations: two-way repeated-measures ANOVA F(5,49) = 2.34, p = 0.056 followed by post hoc Bonferroni t-test vs. CS1 block during fear memory, p < 0.01. All values are expressed as means ± SEM. f Control experiment. Freezing response in PKCδ-Cre− mice not expressing ChR2 and eNpHR in PKCδ neurons. B6 mice: n = 5; freezing, blue light, fear memory, CS I: 63.1 ± 4.9%, extinction learning, CS I: 70.4 ± 9.7%, CS II: 44.6 ± 15.0%, CS III: 26.8 ± 8.2%, CS IV: 31.8 ± 13.5%, extinction memory, CS I: 33.2 ± 3.8%. Yellow light, fear memory, CS I: 64.1 ± 14.2%, extinction learning, CS I: 66.9 ± 12.2%, CS II: 43.9 ± 6.1%, CS III: 32.2 ± 4.1%, CS IV: 26.6 ± 5.7%, extinction memory, CS I: 34.1 ± 12.1% (blocks of 4 CSs). Main effect of CS presentations during extinction: two-way repeated-measures ANOVA F(5,20) = 15.5, p < 0.001. Interaction of light stimulation and CS presentations: two-way repeated-measures ANOVA F(5,20) = 0.12, p = 0.987 followed by post hoc Bonferroni t-test vs. CS1 block during fear memory, p > 0.05 for all comparisons. All values are expressed as means ± SEM. Source data are provided as a Source data file.
