fear conditioning test box  (Med Associates Inc)

Journal: Frontiers in Neuroscience

Article Title: Serotonin Deficiency Increases Context-Dependent Fear Learning Through Modulation of Hippocampal Activity

doi: 10.3389/fnins.2019.00245

Figure Lengend Snippet: Experimental design for c-Fos immunoreactivity after fear conditioning and context-dependent extinction. Tph2 +/+ , Tph2 +/- , and Tph2 -/- mice were exposed to a fear conditioning (FC) protocol and subsequently subjected to a context-dependent extinction protocol. On day 0 mice were placed in the conditioning chamber receiving three pairings of a 20 s tone cue co-terminating with a 2 s foot shock. On day 1 and again on day 2, mice were tested for recall and extinction of context-dependent fear memory using an extinction session consisting of re-exposing the animals to the conditioning context for 800 s without negative reinforcement. Two hours after extinction on day 2, brains were dissected for hippocampal c-Fos expression analysis (EXT) and compared to controls that were left undisturbed in the home cage (CTRL), controls that were exposed to the FC context and tone cue without foot shocks (FS–), and mice that underwent FC with tone-signaled foot shocks (FS+) with brain dissection 2 h after the test .

Article Snippet: Briefly, on day 0, mice were placed by a blinded operator in randomized order into the fear conditioning test box (TSE Systems, Homburg, Germany), which was comprised of a transparent Perspex arena (23 cm × 23 cm × 35 cm) on a stainless steel foot shock grid (floor bars 4 mm diameter, distance rod center to rod center 8.9 mm) that was connected to a shocker-scrambler unit for delivering foot shocks of defined duration and intensity ( ).

Techniques: Expressing, Dissection

Journal: Frontiers in Neuroscience

Article Title: Serotonin Deficiency Increases Context-Dependent Fear Learning Through Modulation of Hippocampal Activity

doi: 10.3389/fnins.2019.00245

Figure Lengend Snippet: Increased context-dependent fear memory recall but effective contextual extinction learning due to 5-HT deficiency. (A) Time-course analysis of the conditioned fear response of Tph2 +/+ , Tph2 +/- , and Tph2 -/- mice during acquisition training showing relative freezing levels before the first pairing of a tone cue with a foot shock (pre-FS), during tone presentations and inter-trial intervals (ITI), and after the last foot shock (post-FS). (B) Unconditioned foot shock reactivity, measured as maximum movement velocity before the first pairing of a tone cue with a foot shock (pre-FS) and following the foot shock (3 × FS). (C) Time-course analysis of the freezing response during contextual fear memory recall and extinction training on day 1 and 2 after conditioning. (D) Average freezing scores in the two extinction sessions. (E) Time-course analysis of the inactivity level during acquisition training showing relative inactivity levels. (F) Positive relationship between freezing scores obtained after the last foot shock (post-FS) in the conditioning session and inactivity scores. Data are shown as means + or ± SEM. ∗ p < 0.05, ∗∗ p < 0.01 and ∗∗∗ p < 0.001.

Article Snippet: Briefly, on day 0, mice were placed by a blinded operator in randomized order into the fear conditioning test box (TSE Systems, Homburg, Germany), which was comprised of a transparent Perspex arena (23 cm × 23 cm × 35 cm) on a stainless steel foot shock grid (floor bars 4 mm diameter, distance rod center to rod center 8.9 mm) that was connected to a shocker-scrambler unit for delivering foot shocks of defined duration and intensity ( ).

Techniques:

Journal: Frontiers in Neuroscience

Article Title: Serotonin Deficiency Increases Context-Dependent Fear Learning Through Modulation of Hippocampal Activity

doi: 10.3389/fnins.2019.00245

Figure Lengend Snippet: Increased c-Fos activity in the dorsal hippocampus (dHip) of Tph2 -/- mice following fear conditioning. ( A , left panel) Overview of the dHip indicating the subregions dentate gyrus (DG), cornu ammonis area 1 (CA1), and cornu ammonis area 3 (CA3) and ( A , right panel) higher magnification images depicting the DG of representative Tph2 -/- mice for the different groups: home cage controls (CTRL), context controls subjected to the conditioning procedure without foot shocks (FS–), fear-conditioned mice receiving three tone-signaled foot shocks (FS+), fear-conditioned mice that underwent two extinction training sessions (EXT). Quantification of c-Fos-ir cell densities in (B) the total dHip, (C) DG, (D) CA1, and (E) CA3 of Tph2 +/+ , Tph2 +/- , and Tph2 -/- mice of the four different groups. Arrowheads in (A) indicate c-Fos-ir cells (red), DAPI-stained cell nuclei (blue). Scale bars in (A) : 200 μm (left panel) and 100 μm (right panel). Data are shown as means + SEM. ∗∗ p < 0.01; ∗∗∗ p < 0.001.

Article Snippet: Briefly, on day 0, mice were placed by a blinded operator in randomized order into the fear conditioning test box (TSE Systems, Homburg, Germany), which was comprised of a transparent Perspex arena (23 cm × 23 cm × 35 cm) on a stainless steel foot shock grid (floor bars 4 mm diameter, distance rod center to rod center 8.9 mm) that was connected to a shocker-scrambler unit for delivering foot shocks of defined duration and intensity ( ).

Techniques: Activity Assay, Staining

Journal: Frontiers in Neuroscience

Article Title: Serotonin Deficiency Increases Context-Dependent Fear Learning Through Modulation of Hippocampal Activity

doi: 10.3389/fnins.2019.00245

Figure Lengend Snippet: Lifelong brain 5-HT synthesis deficiency prevents activation of parvalbumin-ir neurons in fear conditioning. (A) Anti-parvalbumin (PV) (green) and c-Fos (red) immunofluorescent staining with DAPI in the dorsal hippocampus (dHip) of a fear conditioned Tph2 +/- mouse. (B) Magnified with magnified area of cornu ammonis area 1 (CA1). Density of c-Fos/PV-ir cells of home cage control (CTRL) and fear-conditioned (FS+) Tph2 +/+ , Tph2 +/- , and Tph2 -/- mice in (C) dHip and (E) CA1. PV-ir cell density of CTRL and FS+ Tph2 +/+ , Tph2 +/- , and Tph2 -/- mice in (D) dHip and (F) CA1. Data are shown as means + SEM. ∗ p < 0.05; ∗∗ p < 0.01. Two-way ANOVA followed by Fisher’s LSD post hoc test. Scale bar: 100 μm.

Article Snippet: Briefly, on day 0, mice were placed by a blinded operator in randomized order into the fear conditioning test box (TSE Systems, Homburg, Germany), which was comprised of a transparent Perspex arena (23 cm × 23 cm × 35 cm) on a stainless steel foot shock grid (floor bars 4 mm diameter, distance rod center to rod center 8.9 mm) that was connected to a shocker-scrambler unit for delivering foot shocks of defined duration and intensity ( ).

Techniques: Activation Assay, Staining, Control