Source Paper
Facilitation of Conditioned Fear Extinction by Systemic Administration or Intra-Amygdala Infusions of d-Cycloserine as Assessed with Fear-Potentiated Startle in Rats
David L. Walker, Kerry J. Ressler, Kwok-Tung Lu, Michael Davis
Journal of Neuroscience • 2002
Fear Extinction Training
Objective: To evaluate the ability of d-cycloserine (DCS) to facilitate conditioned fear extinction by measuring fear-potentiated startle responses before and after non-reinforced light stimulus presentations
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Equipment1
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Protocol Steps
Fear Conditioning
Rats received pairings of a light stimulus and footshock to establish conditioned fear response
Note: 10 pairings total; light duration 3.7 seconds; footshock intensity 0.4 mA
View evidence from paper
“Rats received 10 pairings of a 3.7 sec light and a 0.4 mA footshock (fear conditioning)”
Baseline Fear-Potentiated Startle Measurement
Measure startle response before extinction training to establish baseline fear-potentiated startle
Note: Measured as increased startle in presence versus absence of light
View evidence from paper
“Fear-potentiated startle was subsequently measured before and after 30, 60, or 90 presentations of the light without shock”
Extinction Training
Present the light stimulus without shock to induce extinction of conditioned fear response
Note: Three conditions tested: 30, 60, or 90 non-reinforced light presentations
View evidence from paper
“30, 60, or 90 presentations of the light without shock (extinction training)”
Post-Extinction Fear-Potentiated Startle Measurement
Measure startle response after extinction training to assess extinction effectiveness
Note: Compared to baseline measurements to determine extinction level
View evidence from paper
“Fear-potentiated startle was subsequently measured before and after 30, 60, or 90 presentations of the light without shock”
Drug Administration (Experiment 2)
Administer DCS systemically at varying doses before extinction training
Note: Three dose levels tested: 3.25, 15, or 30 mg/kg
View evidence from paper
“DCS injections (3.25, 15, or 30 mg/kg) before 30 non-reinforced light exposures dose-dependently enhanced extinction”
Intra-Amygdala DCS Infusion (Experiment 6)
Infuse DCS directly into the amygdala as alternative to systemic administration
Note: 10 μg/side dose used; bilateral infusions implied
View evidence from paper
“The effect of systemic administration was mimicked by intra-amygdala DCS (10 μg/side) infusions”
HA-966 Antagonist Administration (Experiment 4)
Administer HA-966 to block glycine-recognition site and test if DCS effects are blocked
Note: Used to verify mechanism of DCS action
View evidence from paper
“These effects were blocked by HA-966, an antagonist at the glycine-recognition site”
Testing Phase Drug Administration (Experiment 5)
Administer DCS or HA-966 before fear-potentiated startle testing (not extinction training)
Note: Control experiment to test if drugs affect startle measurement itself
View evidence from paper
“Neither DCS nor HA-966 altered fear-potentiated startle when injected before testing”