Study: NCT04468360

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: 3-day differential fear conditioning, extinction, and extinction retention testing paradigm
Description: Day 1: Fear acquisition involving the pairing of a brief, noxious but not painful air blast to the neck (unconditioned stimulus; US) to a conditioned stimuli (CS) (Expts. 1 and 2). The CS will be different colored shapes appearing on a computer monitor. An auditory stimulus will serve as the startle probe. Day 2: Either extinction training (Expt. 1) or fear memory reactivation by a single CS+ with no US (Expt. 2) will occur followed by IV Allo vs. IV placebo administration. Day 3: The effects of IV Allo vs. IV placebo (administered on Day 2) on extinction retention (Expt. 1) or reconsolidation blockade (Expt. 2), as well as reinstatement of conditioned fear (Expts. 1 and 2) will be assessed.

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: 3-day differential fear conditioning, extinction, and extinction retention testing paradigm
Description: Day 1: Fear acquisition involving the pairing of a brief, noxious but not painful air blast to the neck (unconditioned stimulus; US) to a conditioned stimuli (CS) (Expts. 1 and 2). The CS will be different colored shapes appearing on a computer monitor. An auditory stimulus will serve as the startle probe. Day 2: Either extinction training (Expt. 1) or fear memory reactivation by a single CS+ with no US (Expt. 2) will occur followed by IV Allo vs. IV placebo administration. Day 3: The effects of IV Allo vs. IV placebo (administered on Day 2) on extinction retention (Expt. 1) or reconsolidation blockade (Expt. 2), as well as reinstatement of conditioned fear (Expts. 1 and 2) will be assessed.

Intervention type: BEHAVIORAL
Group type: PLACEBO_COMPARATOR
Intervention: 3-day differential fear conditioning, extinction, and extinction retention testing paradigm
Description: Day 1: Fear acquisition involving the pairing of a brief, noxious but not painful air blast to the neck (unconditioned stimulus; US) to a conditioned stimuli (CS) (Expts. 1 and 2). The CS will be different colored shapes appearing on a computer monitor. An auditory stimulus will serve as the startle probe. Day 2: Either extinction training (Expt. 1) or fear memory reactivation by a single CS+ with no US (Expt. 2) will occur followed by IV Allo vs. IV placebo administration. Day 3: The effects of IV Allo vs. IV placebo (administered on Day 2) on extinction retention (Expt. 1) or reconsolidation blockade (Expt. 2), as well as reinstatement of conditioned fear (Expts. 1 and 2) will be assessed.

Intervention type: BEHAVIORAL
Group type: PLACEBO_COMPARATOR
Intervention: 3-day differential fear conditioning, extinction, and extinction retention testing paradigm
Description: Day 1: Fear acquisition involving the pairing of a brief, noxious but not painful air blast to the neck (unconditioned stimulus; US) to a conditioned stimuli (CS) (Expts. 1 and 2). The CS will be different colored shapes appearing on a computer monitor. An auditory stimulus will serve as the startle probe. Day 2: Either extinction training (Expt. 1) or fear memory reactivation by a single CS+ with no US (Expt. 2) will occur followed by IV Allo vs. IV placebo administration. Day 3: The effects of IV Allo vs. IV placebo (administered on Day 2) on extinction retention (Expt. 1) or reconsolidation blockade (Expt. 2), as well as reinstatement of conditioned fear (Expts. 1 and 2) will be assessed.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Allopregnanolone (Allo) with Dexolve in 0.9% saline for injection manufactured by University of California, Davis
Description: Expt. 1 (extinction retention): On Day 2, a 1.7 ug/kg IV bolus of Allo will be administered over 5 minutes at the completion of extinction training and continued as a 5-hour drip to maintain resting plasma Allo levels at \~1500 pg/ml. Expt. 2 (reconsolidation blockade): On Day 2, a 28 ug/kg IV bolus of Allo will be infused over 30 minutes immediately following presentation of a single CS+.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Allopregnanolone (Allo) with Dexolve in 0.9% saline for injection manufactured by University of California, Davis
Description: Expt. 1 (extinction retention): On Day 2, a 1.7 ug/kg IV bolus of Allo will be administered over 5 minutes at the completion of extinction training and continued as a 5-hour drip to maintain resting plasma Allo levels at \~1500 pg/ml. Expt. 2 (reconsolidation blockade): On Day 2, a 28 ug/kg IV bolus of Allo will be infused over 30 minutes immediately following presentation of a single CS+.

Intervention type: OTHER
Group type: PLACEBO_COMPARATOR
Intervention: Matching IV Placebo
Description: Expt. 1 (extinction retention): On Day 2, a 1.7 ug/kg IV bolus of the matching placebo formulation will be administered over 5 minutes at the completion of extinction training and continued as a 5-hour drip to maintain resting plasma Allo levels at \~1500 pg/ml. Expt. 2 (reconsolidation blockade): On Day 2, a 28 ug/kg IV bolus of the matching placebo formulation will be infused over 30 minutes immediately following presentation of a single CS+.

Intervention type: OTHER
Group type: PLACEBO_COMPARATOR
Intervention: Matching IV Placebo
Description: Expt. 1 (extinction retention): On Day 2, a 1.7 ug/kg IV bolus of the matching placebo formulation will be administered over 5 minutes at the completion of extinction training and continued as a 5-hour drip to maintain resting plasma Allo levels at \~1500 pg/ml. Expt. 2 (reconsolidation blockade): On Day 2, a 28 ug/kg IV bolus of the matching placebo formulation will be infused over 30 minutes immediately following presentation of a single CS+.