Article Figures & Data
Figures
- Figure 1.
Experimental design. A, Rats nose poke for food. Independently, cues can be played through overhead speakers, and shocks can be delivered through metal floor bars. B, Minimal threat learning consisted of 10 s auditory cues predicting unique footshock probabilities: threat (red, p = 0.3; purple, p = 0.2; and pink, p = 0.1) and neutral (gray; p = 0). Footshock was 2 s following cue offset on trials it was presented. C, The Mean ± SEM baseline nose poke rate during the cue pre-exposure session (p) and the 10 sessions of shock presentation (1–10) is shown. Baseline nose poke rates are shown because they are used to calculate cue suppression ratio.
- Figure 2.
Responding during minimal threat learning. Mean ± SEM suppression ratios for threat (red, p = 0.3; purple, p = 0.2; and pink, p = 0.1) and neutral (gray, p = 0) from pre-exposure (p) through the 10 minimal threat learning sessions (1–10) are shown for rats in the (A) 30%, (B) 20%, and (C) 10% probability conditions. D, Group Mean (bars) and individual (female, filled; male, open) change in suppression ratio from Session 1 to Sessions 2–4 (Mean) are shown. The +95% BCI does not contain zero.
- Figure 3.
Responding during extinction test. A, Group Mean (bars) and individual (female, filled; male, open) suppression ratios for threat (red, p = 0.3; purple, p = 0.2; and pink, p = 0.1) and neutral (gray, p = 0) from the extinction test are shown. B, Group Mean and individual baseline nose poke rates are shown (color as in A). *Independent samples t test, p < 0.05.
- Figure 4.
Dual viral approach and GFP/deletion mapping. A, Control rats received bilateral rAAV2-retro and mCherry infusions into the ventral pallidum. B, Casp3VP rats received bilateral rAAV2-retro and cre-dependent caspase-3 into the ventral pallidum. The ventral pallidum indicated in red. Representative fluorescent images of subcommissural ventral pallidum are shown for (C) controls and for (D) Casp3VP rats (substance P, magenta; GFP, yellow). E, Individual control rat GFP expression (green–yellow) was mapped at bregma levels +0.36, 0.00, and −0.36, made transparent then overlayed. Areas of darker green–yellow indicate areas of more consistent GFP expression. F, Individual Casp3VP rat neuronal deletion (blue) was mapped at bregma levels +0.36, 0.00, and −0.36, made transparent then overlayed. Areas of darker blue indicate areas of more consistent neuronal deletion. The ventral pallidum border is outlined in red for both E and F. Representative NeuroTrace images from a control and Casp3VP rat are shown in Extended Data Figure 4-1.
- Figure 5.
Quantifying GFP, experimental design, and baseline nose poke rate. A, Group Mean (bars) and individual (female, filled; male, open) ventral pallidum neuron number is shown for control (circles) and Casp3VP rats (triangles). B, Minimal threat learning procedure consisted of 10 s auditory cues predicting unique footshock probabilities: threat (red, p = 0.3, and pink, p = 0.1) and neutral (gray, p = 0). The Mean ± SEM baseline nose poke rate from pre-exposure (p) through the 10 minimal threat learning sessions (1–10) is shown for control (circles) and Casp3VP rats (triangles) in the (C) 30% (red) and (D) 10% (pink) probability conditions.
- Figure 6.
Control and Casp3VP responding during minimal threat learning. Mean ± SEM suppression ratios for threat (red, p = 0.3, and pink, p = 0.1) and neutral (gray, p = 0) from pre-exposure (p) through the 10 minimal threat learning sessions (1–10) are shown for (A) control (circles) and (B) Casp3VP rats (triangles) in the 30% probability condition and (C, D) the 10% probability condition.
- Figure 7.
Control and Casp3VP responding during extinction test. A, Group Mean (bars) and individual (female, filled; male, open) suppression ratios for threat (red, p = 0.3, and pink, p = 0.1) and neutral (gray, p = 0) from the extinction test are shown control (left, circles) and CaspVP rats (right, triangles). B, Group Mean and individual baseline nose poke rates are shown (color and shape as in A). *Independent samples t test, p < 0.05.
- Figure 8.
Histology, experimental design, and baseline nose poke rate. A, All rats received bilateral rAAV2-retro infusions into the ventral pallidum (left). Control rats received mCherry infusions into the nucleus accumbens core, while Casp3NAcc→VP rats received cre-dependent caspase-3 infusions into the nucleus accumbens core (right). Representative fluorescent images of the nucleus accumbens show GFP+ neurons in (B) controls but not in (C) Casp3NAcc→VP rats. The accumbens core and anterior commissure are outlined. Representative fluorescent images of the ventral pallidum show GFP + neurons in (D) controls and in (E) Casp3NAcc→VP rats. The anterior commissure is outlined. Group Mean (bars) and individual (female, filled; male, open) nucleus accumbens neuron number (F) and ventral pallidum neuron number (G) are shown for control (circles) and Casp3VP (triangles). H, Minimal threat learning procedure consisted of 10 s auditory cues predicting unique footshock probabilities: threat (red, p = 0.3) and neutral (gray, p = 0). I, M ± SEM baseline nose poke rate from pre-exposure (p) through the 10 minimal threat learning sessions (1–10) is shown for control (circles) and Casp3NAcc→VP rats (triangles). *Independent samples t test, p < 0.05.
- Figure 9.
Control and Casp3NAcc→VP responding during minimal threat learning and extinction. Mean ± SEM suppression ratios for threat (red, p = 0.3) and neutral (gray, p = 0) from pre-exposure (p) through the 10 minimal threat learning sessions (1–10) are shown for (A) control (circles) and (B) Casp3NAcc→VP rats (triangles). C, Group Mean (bars) and individual (female, filled; male, open) suppression ratios for threat (red, p = 0.3, and pink, p = 0.1) and neutral (gray, p = 0) from the extinction test are shown for control (left, circles) and Casp3NAcc→VP rats (right, triangles). D, Group Mean and individual baseline nose poke rates from the extinction test are shown for control and Casp3NAcc→VP rats (color and shape as in D). *Independent samples t test, p < 0.05. A single rat that did not poke during testing is outlined with an additional triangle in C and D.
Tables
Term Definition Fear learning Acquiring a behavioral response to a threat cue paired with shock Fear discrimination Differential responding to a threat cue (paired with shock) and a neutral cue (not paired with shock) Fear generalization Threat-like responding to a neutral cue Operationalized definitions for fear learning, fear discrimination, and fear generalization.
Group Probability Sex n Experiment 1 30% Female 8 30% Male 8 20% Female 8 20% Male 8 10% Female 7 10% Male 8 Experiment 2 ControlVP 30% Female 3 ControlVP 30% Male 3 ControlVP 10% Female 3 ControlVP 10% Male 3 Casp3VP 30% Female 3 Casp3VP 30% Male 3 Casp3VP 10% Female 2 Casp3VP 10% Male 3 Experiment 3 ControlNAc→VP 30% Female 6 ControlNAc→VP 30% Male 6 Casp3NAc→VP 30% Female 6 Casp3NAc→VP 30% Male 6 The number of rats in each surgical group and footshock probability condition are shown by sex.
Figure 4-1
Representative NeuroTrace Images from Experiment 2 (A) A coronal section from a control rat containing the ventral pallidum is stained with NeuroTrace. The anterior commissure (AC) is outline in white. Sub-commissural ventral pallidum neurons are intact. (B) A coronal section from a caspase-3 rat containing the ventral pallidum is stained with NeuroTrace. The anterior commissure (AC) is outlined in white. Sub-commissural ventral pallidum neurons are deleted with little or no evidence of remaining neurons. Download Figure 4-1, TIF file.
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