Source Paper
David L. Walker, Kerry J. Ressler, Kwok-Tung Lu, Michael Davis
Journal of Neuroscience • 2002
NMDA receptor antagonists block conditioned fear extinction when injected systemically and also when infused directly into the amygdala. Here we evaluate the ability of d -cycloserine (DCS), a partial agonist at the strychnine-insensitive glycine-recognition site on the NMDA receptor complex, to facilitate conditioned fear extinction after systemic administration or intra-amygdala infusions. Rats received 10 pairings of a 3.7 sec light and a 0.4 mA footshock (fear conditioning). Fear-potentiated startle (increased startle in the presence vs the absence of the light) was subsequently measured before and after 30, 60, or 90 presentations of the light without shock (extinction training). Thirty non-reinforced light presentations produced modest extinction, and 60 or 90 presentations produced nearly complete extinction (experiment 1). DCS injections (3.25, 15, or 30 mg/kg) before 30 non-reinforced light exposures dose-dependently enhanced extinction (experiment 2) but did not influence fear-potentiated startle in rats that did not receive extinction training (experiment 3). These effects were blocked by HA-966, an antagonist at the glycine-recognition site (experiment 4). Neither DCS nor HA-966 altered fear-potentiated startle when injected before testing (experiment 5). The effect of systemic administration was mimicked by intra-amygdala DCS (10 µg/side) infusions (experiment 6). These results indicate that treatments that promote NMDA receptor activity after either systemic or intra-amygdala administration promote the extinction of conditioned fear.
Objective: To evaluate the ability of d-cycloserine (DCS) to facilitate conditioned fear extinction in rats as assessed with fear-potentiated startle
This is a Fear Conditioning protocol using rat as the model organism. The procedure involves 9 procedural steps, 2 equipment items, 2 materials. Extracted from a 2002 paper published in Journal of Neuroscience.
Model and subjects
rat • Not specified • Not specified • Not specified • Not specified • Not specified
Study window
Estimated timing pending
Core workflow
Fear Conditioning • Baseline Fear-Potentiated Startle Measurement • Extinction Training
Primary readouts
Key equipment and reagents
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Rats received pairings of a light stimulus and footshock to establish conditioned fear responses
Note: 10 pairings total with 3.7 second light and 0.4 mA footshock
“Rats received 10 pairings of a 3.7 sec light and a 0.4 mA footshock (fear conditioning)”
Fear-potentiated startle was measured before extinction training to establish baseline responses
Note: Measured as increased startle in presence vs absence of light
“Fear-potentiated startle (increased startle in the presence vs the absence of the light) was subsequently measured before and after”
Rats received non-reinforced light presentations without shock to extinguish the conditioned fear response
Note: Light presented without accompanying footshock
“30, 60, or 90 presentations of the light without shock (extinction training)”
Fear-potentiated startle was measured after extinction training to assess extinction learning
Note: Compared to baseline measurements
“Fear-potentiated startle (increased startle in the presence vs the absence of the light) was subsequently measured before and after”
DCS was injected systemically before non-reinforced light exposures to test dose-dependent effects on extinction
Note: Three dose levels tested: 3.25, 15, or 30 mg/kg
“DCS injections (3.25, 15, or 30 mg/kg) before 30 non-reinforced light exposures dose-dependently enhanced extinction”
DCS was administered to rats that did not receive extinction training to test for non-specific effects on fear-potentiated startle
Note: Control to verify DCS does not influence startle without extinction training
“DCS injections (3.25, 15, or 30 mg/kg) before 30 non-reinforced light exposures dose-dependently enhanced extinction but did not influence fear-potentiated startle in rats that did not receive extinction training”
HA-966 was administered to block the glycine-recognition site and test whether DCS effects are mediated through this site
Note: HA-966 blocked the extinction-enhancing effects of DCS
“These effects were blocked by HA-966, an antagonist at the glycine-recognition site”
DCS or HA-966 were injected before testing to determine if they affect startle measurement itself
Note: Neither drug altered fear-potentiated startle when given before testing
“Neither DCS nor HA-966 altered fear-potentiated startle when injected before testing”
DCS was infused directly into the amygdala before extinction training to test local effects
Note: 10 µg/side dose used; effects mimicked systemic administration
“The effect of systemic administration was mimicked by intra-amygdala DCS (10 µg/side) infusions”
This section explains what the experiment is doing, which readouts matter, what the data artifacts usually look like, and how the analysis should flow from raw capture to reported result.
To evaluate the ability of d-cycloserine (DCS) to facilitate conditioned fear extinction in rats as assessed with fear-potentiated startle
Objective
To evaluate the ability of d-cycloserine (DCS) to facilitate conditioned fear extinction in rats as assessed with fear-potentiated startle
Subjects
From paperrat • Not specified • Not specified • Not specified • Not specified
Sample count
From paperNot specified
Cohort notes
From paperNone specified
Fear Conditioning (Not specified)
Baseline Fear-Potentiated Startle Measurement (Not specified)
Extinction Training (30, 60, or 90 presentations depending on experiment)
Post-Extinction Fear-Potentiated Startle Measurement (Not specified)
Fear-potentiated startle response (increased startle in presence vs absence of light)
From paperNot specified in provided text
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Extinction learning as measured by reduction in fear-potentiated startle after non-reinforced light presentations
From paperNot specified in provided text
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Dose-dependent effects of DCS on extinction
From paperNot specified in provided text
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Effects of HA-966 antagonist on DCS-mediated extinction enhancement
From paperNot specified in provided text
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Fear-potentiated startle response (increased startle in presence vs absence of light)
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Extinction learning as measured by reduction in fear-potentiated startle after non-reinforced light presentations
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Dose-dependent effects of DCS on extinction
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Effects of HA-966 antagonist on DCS-mediated extinction enhancement
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Acquisition
Collect raw experimental outputs with enough metadata to preserve sample identity, condition, and timing.
Preprocessing / cleaning
Not specified in provided text
Scoring or quantification
Quantify the primary readouts for this experiment: Fear-potentiated startle response (increased startle in presence vs absence of light); Extinction learning as measured by reduction in fear-potentiated startle after non-reinforced light presentations; Dose-dependent effects of DCS on extinction; Effects of HA-966 antagonist on DCS-mediated extinction enhancement.
Statistical comparison
Statistical method not yet structured for this page.
Reporting output
Report representative outputs alongside summary comparisons for Fear-potentiated startle response (increased startle in presence vs absence of light), Extinction learning as measured by reduction in fear-potentiated startle after non-reinforced light presentations, Dose-dependent effects of DCS on extinction, Effects of HA-966 antagonist on DCS-mediated extinction enhancement.
Source links and direct wording from the methods section for validation and deeper review.
Citation
David L. Walker et al. (2002). Facilitation of Conditioned Fear Extinction by Systemic Administration or Intra-Amygdala Infusions of d-Cycloserine as Assessed with Fear-Potentiated Startle in Rats. Journal of Neuroscience
Fear Conditioning • Protocol step
“Rats received 10 pairings of a 3.7 sec light and a 0.4 mA footshock (fear conditioning)”
Baseline Fear-Potentiated Startle Measurement • Protocol step
“Fear-potentiated startle (increased startle in the presence vs the absence of the light) was subsequently measured before and after”
Extinction Training • Protocol step
“30, 60, or 90 presentations of the light without shock (extinction training)”
DCS Administration (Experiment 2) • Protocol step
“DCS injections (3.25, 15, or 30 mg/kg) before 30 non-reinforced light exposures dose-dependently enhanced extinction”
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