fear conditioning arena  (Med Associates Inc)

Journal: Cells

Article Title: Dendrimer-Conjugated Glutamine Antagonist, D-TTM020, Ameliorates Brain Immune Dysregulation and Improves Neurobehavioral Deficits in the Mecp2- Deficient Mouse Model

doi: 10.3390/cells15030272

Figure Lengend Snippet: D-TTM020 restores contextual fear memory in Mecp2 het mice. ( A ) Fear-conditioning paradigm, ( B ) contextual fear memory. D-TTM020-treated hets rescued conditioned fear memory to baseline levels. ( C ) Fear extinction test (Cue response). D-TTM020 improved contextual fear memory and cue response in Mecp2 hets versus saline and free TTM020. *** p < 0.001, ** p < 0.01, * p < 0.05 in comparison to the saline-treated hets. Data is represented as mean ± SD. n = 9–13/group.

Article Snippet: Contextual fear conditioning: On day 1, the mice were introduced to a fear-conditioning arena (10.75′′ × 9.97′′ × 11.25′′; Med Associates, St. Albans, VT, USA) and allowed to habituate for two minutes.

Techniques: Saline, Comparison

Journal: Frontiers in Synaptic Neuroscience

Article Title: NPY Released From GABA Neurons of the Dentate Gyrus Specially Reduces Contextual Fear Without Affecting Cued or Trace Fear

doi: 10.3389/fnsyn.2021.635726

Figure Lengend Snippet: Activation of GABA neurons in the dorsal dentate gyrus reduces fear expression. (A) Upper image: schematic illustration of the injection site of rAAV-hSyn-DIO-hM3DGq-mCherry (Gq) or rAAV-hSyn-DIO-hM4DGi-mCherry (Gi) in the dorsal dentate gyrus (DG) of VGAT-cre mice. Lower image: immunohistochemical distribution of mCherry in the dorsal DG (arrows point towards individual immuno-positive GABA neurons). (B) Schematic fear conditioning protocol. On day 1 (D1), five pairings of a CS (20 s) followed by a 5 s trace and a 0.5 mA footshock were delivered with a variable inter-trial interval of 40–60 s. On day 2 (D2), mice were placed into the acquisition context for 25 min. On day 3 (D3), mice were injected with 1 mg/kg clozapine-N-oxide (CNO) 30 min before fear recall testing, consisting of 5CS presentations in a different context. (C) Equal fear acquisition for all groups, (D) no change in contextual fear, (E) during testing of CS-induced fear recall, Gq group showed a lower percentage of freezing than Gi and saline during 5 CS as demonstrated by two-way ANOVA for repeated measurements and Tukey’s post hoc test. (F) A similar reduction of the percentage of freezing was seen during the trace period. (G) Saline, Gq, and Gi injected mice showed a higher percentage of freezing during the trace period compared to the CS, suggesting intact stimulus contingency. Data are presented as means ± SEM, * P < 0.05. Saline: n = 11, Gi: n = 6, Gq: n = 14. Abbreviation: CS, conditioned stimulus.

Article Snippet: In brief, trace fear acquisition was performed in context A, consisting of a fear conditioning arena made of a transparent acrylic chamber with a metal grid floor (Ugo Basile, Italy).

Techniques: Activation Assay, Expressing, Injection, Immunohistochemical staining, Saline