Journal: bioRxiv

Article Title: The Reinstatement of a Forgotten Infantile Memory

doi: 10.1101/2025.09.27.678956

Figure Lengend Snippet: (A) Schematic of the behavioral protocol to trigger reinstatement of a forgotten infantile memory. Mice underwent contextual fear conditioning (cFC) training in infancy (P19), followed in adulthood by exposure to reminders of the CONTEXT and the AVERSIVE stimulus experienced during cFC training. The recall of the reinstated memory (REINSTATED recall) was tested in the CONTEXT one day after the final reminder. All behavioral sessions in adulthood were spaced by one day. (B) Freezing at CONTEXT reminder in adulthood was low in mice fear conditioned at P19, similar to animals that never experienced conditioning (Naϊve animals. Dunnett’s test, p = 0.634), and significantly higher in adult-conditioned animals (p < 0.001), indicating infantile amnesia. One-way ANOVA, F(2, 38) = 51.93, p < 0.001, r2 = 0.7321. n 2 11 mice per group. (C) At REINSTATED recall, mice conditioned at P19 expressed robust freezing (Dunnett’s test, p = 0.007), significantly higher than naϊve animals and comparable to animals conditioned during adulthood (> P60) only when both CONTEXT and AVERSIVE reminders were given. No reinstatement was observed in animals lacking either the CONTEXT (Dunnett’s test, p = 0.970) or the AVERSIVE (p > 0.999) reminder. One-way ANOVA, F(25, 226) = 11.18, p < 0.001, r2 = 0.5529; Brown-Forsythe test, F(25, 226) = 2.622, p < 0.001; Bartlett’s test, x2 = 81.17, p < 0.001. n 2 9 mice per group. (D) AAV-mediated expression of excitatory DREADD (hM3Dq-mCherry, yellow) in PV interneurons of dorsal hippocampus. Representative histological image showing mCherry expression in PV+ neurons in dorsal CA3 and CA1 (single-plane image, 10x objective; scale bar = 300 µm). (E, F) Activation of hippocampal PV interneurons via CNO injection during either the CONTEXT (E) or AVERSIVE (F) reminder prevented memory reinstatement, resulting in low freezing at REINSTATED recall. Student’s t -test against saline injected controls: CONTEXT, t = 3.515, p = 0.004, Cohen’s d = 0.507; AVERSIVE, t = 4.04, p = 0.003, Cohen’s d = 0.645. n = 6 for CONTEXT, n 2 4 for AVERSIVE.

Article Snippet: To induce the encoding of a hippocampus-dependent associative memory through contextual fear conditioning (cFC) during infancy, P19 mouse pups (“cFC P19” group) were placed in a conditioning chamber (training context (TR), Ugo Basile; tracking software: EthoVision XT, versions 14-17, Noldus), which consisted of a square box (25 x 25 cm) with a grid floor (fine spacing, electrifiable), patterned walls (stripes and squares), and a distinct odor (2% acetic acid).

Techniques: Expressing, Activation Assay, Injection, Saline

Journal: bioRxiv

Article Title: Adolescent Alcohol Exposure Disrupts Astrocyte-Synaptic Structural And Functional Coupling In The Male Dorsal Hippocampus

doi: 10.1101/2025.10.14.682478

Figure Lengend Snippet: a. Schematic representation of intracranial injection of the astrocyte membrane-specific adeno-associated virus (AAV5.GFAP.hM3D(Gq).mCherry) in the dHipp on PND 26. Beginning at PND 30, animals received AIE or H 2 O intermittently through PND 45. Following 26 day forced abstinence period, animals received saline or clozapine-N-oxide (CNO, i.p. 2 mg/kg) to activate astrocytes. After 30 minutes, animals were assessed in a contextual fear conditioning paradigm. Animals were placed in context A and subjected to 3-foot shocks across a 10-minute test period on day 1. On day 2 and 3, animals were placed in context A for 12 min with no foot shocks. b. Representative images of the dHipp, DAPI (blue), hM3DGq (magenta), GFAP (green), and colocalization of GFAP+hM3DGq confirming astrocyte specificity of AAV. c. Representative images of DeepLabCut output of labeled body parts on the x-y axis of the context box. d. Quantification of freezing behavior in the CFC task (H 2 O+SAL (#) vs. AIE+SAL ($); p = 0.029-0.085; H 2 O+CNO (&) vs. AIE+CNO (@); p = 0.062-0.574 ). e-f . Freeze/dart behavior quantification from sessions collapsed across foot shocks from Day 1 of the CFC. g-h. Freeze/dart behavior quantification from Days 2 and 3 of the CFC. Analysis: Repeated measures Two-way ANOVA, n = 12 animals/treatment group across 2 separate cohorts. ( p < 0.05* p < 0.001**)

Article Snippet: Following the 26-day forced abstinence period, animals underwent a 3-day contextual fear conditioning (CFC) paradigm previously described using Med Associates operant chambers.

Techniques: Injection, Membrane, Virus, Saline, Labeling