Cognitive vs. Emotional Psychopharmacological Manipulations of Fear vs. Anxiety

Cognitive vs. Emotional Psycho-Pharmacological Manipulations of Fear vs. Anxiety

Objective:

The overall aim of this protocol is to examine the effect of pharmacological manipulations of affective and cognitive processes on anxiety and task performance. Ultimately, the goal is 1) to provide insight into the relative influence of cognitive and affective states on anxiety, 2) generate theoretical models that can be applied to a better understanding of the interaction between cognition and emotion, 3) develop a better screening approach to candidate anxiolytics, and 4) help formulate novel therapeutic interventions for clinical anxiety.

Excessive or inappropriately sustained anxiety and fear lead to the most common group of psychiatric disorders. A number of theoretical models have been proposed to understand the mechanisms engaged in these maladaptive behaviors. Most recent emphasis has focused on the synergistic contribution of cognitive and emotional processes. Our laboratory has been instrumental in delineating aspects of behavioral and neural processes that are associated with fear and anxiety, using psychophysiological and neuroimaging measures of fear and anxiety. Evidence shows that levels of anxiety modulate cognitive performance, such as working memory or perceptual discrimination, and that, conversely, cognitive engagement influences severity of experimentally induced anxiety. The exact contribution of emotional processes vs. cognitive processes to the experience of anxiety is not clear, similarly to the neural mechanisms underlying these interactions.

In this protocol, we propose to manipulate pharmacologically separately cognitive and emotional processes to dissociate their contribution to fear/anxiety, while using state-of-the-art measures of anxiety derived from translational work. Indeed, we already developed integrative experimental models of fear and anxiety via the manipulation of predictable and unpredictable shock, respectively. We already employed successfully these models to measure anxiolytic and anxiogenic effects of various compounds such as alprazolam, citalopram, hydrocortisone, and oxytocin in healthy participants.

We propose in a first step (step-1) to start with a simple proof-of-concept study, using two pharmacological compounds in a double-blind randomized parallel design, each preferentially acting respectively on the cognitive (methylphenidate) or affective (propranolol) domain, and using a single cognitive process (working memory). In a second step (step-2), we propose to extend this work to the fMRI to examine the cognitive correlates of the effects seen in the step-1 behavioral study, specifically with methylphenidate. Whereas the comparison among three drugs is planned for the electrophysiology study, we plan to study only the drug that improves cognition in the fMRI. The reason we will focus on methylphenidate in step 2 is that our overall goal is to study the effect of improving cognitive functions on anxiety using neuroimaging. To reach this goal, we plan to use different approaches to boost cognitive functions in the coming years, including psychopharmacology, direct current stimulation, mindfulness. Methylphenidate is our first psychopharmacological study towards this objective. Future work will also expand to other compounds and cognitive processes, as well as vary the strategy to induce anxiety. Presently, anxiety will be induced using the threat of shock, while participants perform the task. We will examine in step-1 whether 1) the reduction of induced-anxiety with propranolol improves cognitive performance, and 2) the facilitation of cognitive performance with methylphenidate reduces induced-anxiety. In step-2, we will identify the neural mechanisms underlying the effects of methylphenidate, the drug having beneficial effects on cognitive function.

Study population:

Medically and psychiatrically healthy adult males and females, aged 18 to 50 years.

Design:

The study is a double-blind design. For step-1, three groups of healthy participants will come for one experimental session. During this session, they will be asked to perform a working memory task under the threat of shock, i.e., while anticipating unpleasant electric shocks. Each group will receive one drug challenge, either placebo, propranolol (40 g) or methylphenidate (20 mg). For step-2, the study tasks will be conducted in a 3T fMRI scanner. In this step, only methylphenidate and placebo will be compared. Two groups will come for one experimental session, one will receive placebo and the other one will receive methylphenidate (20 mg). In a follow-up study for the step-2 fMRI the two groups will come for one experimental fMRI session one will receive methylphenidate (60 mg).

Outcome measures:

In step-1, the primary outcome measures are the startle reflex and performance on the working memory task. In step-2, the primary outcome measures are the startle reflex and the cerebral fMRI blood-oxygen-level ...

Study Overview

Status

Completed

Conditions

Detailed Description

Objective:

The overall aim of this protocol is to examine the effect of pharmacological manipulations of affective and cognitive processes on anxiety and task performance. Ultimately, the goal is 1) to provide insight into the relative influence of cognitive and affective states on anxiety, 2) generate theoretical models that can be applied to a better understanding of the interaction between cognition and emotion, 3) develop a better screening approach to candidate anxiolytics, and 4) help formulate novel therapeutic interventions for clinical anxiety.

Excessive or inappropriately sustained anxiety and fear lead to the most common group of psychiatric disorders. A number of theoretical models have been proposed to understand the mechanisms engaged in these maladaptive behaviors. Most recent emphasis has focused on the synergistic contribution of cognitive and emotional processes. Our laboratory has been instrumental in delineating aspects of behavioral and neural processes that are associated with fear and anxiety, using psychophysiological and neuroimaging measures of fear and anxiety. Evidence shows that levels of anxiety modulate cognitive performance, such as working memory or perceptual discrimination, and that, conversely, cognitive engagement influences severity of experimentally induced anxiety. The exact contribution of emotional processes vs. cognitive processes to the experience of anxiety is not clear, similarly to the neural mechanisms underlying these interactions.

In this protocol, we propose to manipulate pharmacologically separately cognitive and emotional processes to dissociate their contribution to fear/anxiety, while using state-of-the-art measures of anxiety derived from translational work. Indeed, we already developed integrative experimental models of fear and anxiety via the manipulation of predictable and unpredictable shock, respectively. We already employed successfully these models to measure anxiolytic and anxiogenic effects of various compounds such as alprazolam, citalopram, hydrocortisone, and oxytocin in healthy participants.

We propose in a first step (step-1) to start with a simple proof-of-concept study, using two pharmacological compounds in a double-blind randomized parallel design, each preferentially acting respectively on the cognitive (methylphenidate) or affective (propranolol) domain, and using a single cognitive process (working memory). In a second step (step-2), we propose to extend this work to the fMRI to examine the cognitive correlates of the effects seen in the step-1 behavioral study, specifically with methylphenidate. Whereas the comparison among three drugs is planned for the electrophysiology study, we plan to study only the drug that improves cognition in the fMRI. The reason we will focus on methylphenidate in step 2 is that our overall goal is to study the effect of improving cognitive functions on anxiety using neuroimaging. To reach this goal, we plan to use different approaches to boost cognitive functions in the coming years, including psychopharmacology, direct current stimulation, mindfulness. Methylphenidate is our first psychopharmacological study towards this objective. Future work will also expand to other compounds and cognitive processes, as well as vary the strategy to induce anxiety. Presently, anxiety will be induced using the threat of shock, while participants perform the task. We will examine in step-1 whether 1) the reduction of induced-anxiety with propranolol improves cognitive performance, and 2) the facilitation of cognitive performance with methylphenidate reduces induced-anxiety. In step-2, we will identify the neural mechanisms underlying the effects of methylphenidate, the drug having beneficial effects on cognitive function.

Study population:

Medically and psychiatrically healthy adult males and females, aged 18 to 50 years.

Design:

The study is a double-blind design. For step-1, three groups of healthy participants will come for one experimental session. During this session, they will be asked to perform a working memory task under the threat of shock, i.e., while anticipating unpleasant electric shocks. Each group will receive one drug challenge, either placebo, propranolol (40 g) or methylphenidate (20 mg). For step-2, the study tasks will be conducted in a 3T fMRI scanner. In this step, only methylphenidate and placebo will be compared. Two groups will come for one experimental session, one will receive placebo and the other one will receive methylphenidate (20 mg). In a follow-up study for the step-2 fMRI the two groups will come for one experimental fMRI session one will receive methylphenidate (60 mg).

Outcome measures:

In step-1, the primary outcome measures are the startle reflex and performance on the working memory task. In step-2, the primary outcome measures are the startle reflex and the cerebral fMRI blood-oxygen-level dependent (BOLD) responses. For both step-1 and step-2, secondary measures include skin conductance, heart rate, and subjective measures of anxiety.

Study Type

Interventional

Enrollment (Actual)

142

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Maryland
      • Bethesda, Maryland, United States, 20892
        • National Institutes of Health Clinical Center, 9000 Rockville Pike

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 48 years (Adult)

Accepts Healthy Volunteers

No

Description

  • INCLUSION CRITERIA:
  • Ages 18-50
  • Males and females
  • Subjects give their own consent

EXCLUSION CRITERIA:

  • Clinically significant prior exposure to medications, that based on the investigator s judgment, may impact the study, such as Ritalin (MPH).
  • Any significant medical or neurological problems (e.g. cardiovascular illness, respiratory illness, neurologic illness, seizure, etc.)
  • Raynaud syndrome
  • IQ < 80
  • Sinus bradycardia (P<45), or tachycardia (P>90)
  • Significant ECG abnormality (i.e., greater than first-degree block etc.) as determined by investigators judgement
  • High or low blood pressure (SBP>140 or SBP<90; SDP<50 or SDP>90)
  • A first-degree family history of mania, schizophrenia, or other psychoses based on verbal reports
  • Significant past psychopathology (e.g., hospitalization for psychiatric disorders, recurrent depression, suicide attempt, psychoses)
  • Current psychiatric disorders according to Diagnostic and Statistical Manual (DSM)-V
  • Current alcohol or substance use disorder
  • Current use of psychotropic medication
  • Impaired hearing (clinic study only)
  • Pregnancy or positive pregnancy test
  • Neurological syndrome of the wrist (e.g., carpal tunnel syndrome) for shocks to be delivered on affected arm.
  • Breastfeeding
  • Significant lab abnormalities (i.e., complete blood count (CBC) with differential, acute care and mineral panel, hepatic panel, TSH)
  • Positive urine toxicology screen
  • You have been in another study with an experimental medication within the previous month
  • For physiological/clinic participants: small startle reactivity (a change in EMG activity that is less than 3 times the baseline EMG activity)
  • Current daily use of anti-acid -medication or within 5 half-lives of study visit if taken on pro re nata (PRN) basis
  • Employee of National Institute of Mental Health (NIMH) or an immediate family member who is a NIMH employee.
  • For functional magnetic resonance imaging (fMRI) participants: Any medical condition that increases risk for fMRI:

    • Any metal implants (clips, screws, plates, pins, etc.) that are not safe for MRI or metal fragments cause by injuries or metal working. Metal implants that are deemed MRI safe are allowable (i.e. certain screws).
    • Any sort of medical implants that are not safe for the MRI (aneurysm clips, pacemaker, insulin pump, Hickman line, etc.). Medical implants that are MRI safe (Nexplanon implant, certain intrauterine device (IUDs), etc.) are allowable.
    • Permanent eye liner and tattoos above the neck
    • Patients who have difficulty lying flat on their back for up to 90 min in the scanner
    • Participants who are uncomfortable in small closed spaces (have claustrophobia) and would feel uncomfortable in the MRI machine

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Behavioral: Drug challenge with methylphenidate
Participant received methylphenidate 20 mg orally during study visit
Methylphenidate 20mg was given orally during study visit
Placebo Comparator: Behavioral: Drug challenge with placebo
Participant received placebo orally during study visit
Placebo was given orally during study visit
Experimental: Behavioral: Drug challenge with propranolol
Participants received propranolol 40mg orally during study visit
Propranolol 40 mg was given orally during study visit
Experimental: fMRI: Drug challenge with methylphenidate
Participant received methylphenidate 20 mg orally during study visit
Methylphenidate 20mg was given orally during study visit
Placebo Comparator: fMRI: Drug challenge with placebo
Participant received placebo orally during study visit
Placebo was given orally during study visit

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Magnitude of Startle Reflex During Safe Condition
Time Frame: 20-120 milliseconds following the onset of the startle stimulus
The magnitude of the startle reflex during working memory tasks (n-back) while undergoing alternating periods of safety and threat of shock. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. The participant holds each stimulus in short-term memory while new stimuli are presented. For each new item presented, the participant's task is to decide if it is the same as the stimulus presented one time before (1Back), two times before (2Back) or three times before (3Back) by responding "yes" if the stimulus currently presented matches the stimulus presented earlier. Participants responded with a button press. The startle reflex was elicited with a 102 decibel (dB) white noise (40-ms duration) delivered via headphone. The eyeblink component of the startle reflex was recorded binaurally with two silver chloride (AgCl) electrodes placed under one eye.
20-120 milliseconds following the onset of the startle stimulus
Magnitude of Startle Reflex During Threat Condition
Time Frame: 20-120 milliseconds following the onset of the startle stimulus
The magnitude of the startle reflex during working memory tasks (n-back) while undergoing alternating periods of safety and threat of shock. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. The participant holds each stimulus in short-term memory while new stimuli are presented. For each new item presented, the participant's task is to decide if it is the same as the stimulus presented one time before (1Back), two times before (2Back) or three times before (3Back) by responding "yes" if the stimulus currently presented matches the stimulus presented earlier. Participants responded with a button press. The startle reflex was elicited with a 102 decibel (dB) white noise (40-ms duration) delivered via headphone. The eyeblink component of the startle reflex was recorded binaurally with two silver chloride (AgCl) electrodes placed under one eye.
20-120 milliseconds following the onset of the startle stimulus
Proportion of Correct Responses in the Working Memory Task (N-back) - Safe Condition
Time Frame: Task started 90 minutes post drug admin up to max of 125 mins post drug admin (max total is 35 mins) during a 6-hour single day visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one, two, or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. The participant holds each stimulus in short-term memory while new stimuli are presented. For each new item presented, the participant's task is to decide if it is the same as the stimulus presented one time before (1Back), two times before (2Back) or three times before (3Back)" by responding "yes" if the stimulus currently presented matches the stimulus presented earlier. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1Back, 2Back, 3Back) using repeated measures ANOVA.
Task started 90 minutes post drug admin up to max of 125 mins post drug admin (max total is 35 mins) during a 6-hour single day visit
Proportion of Correct Responses in the Working Memory Task (N-back) - Threat Condition
Time Frame: task started 90 minutes post drug admin up to max of 125 mins post drug admin (max total is 35 mins) during a 6-hour single day visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one, two, or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. The participant holds each stimulus in short-term memory while new stimuli are presented. For each new item presented, the participant's task is to decide if it is the same as the stimulus presented one time before (1Back), two times before (2Back) or three times before (3Back)" by responding "yes" if the stimulus currently presented matches the stimulus presented earlier. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1Back, 2Back, 3Back) using repeated measures ANOVA.
task started 90 minutes post drug admin up to max of 125 mins post drug admin (max total is 35 mins) during a 6-hour single day visit
Proportion of Correct Responses in the Working Memory Task (N-Back): Safe Condition - 1BACK - Run 1
Time Frame: 90 minutes post drug admin plus zero seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe).Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes post drug admin plus zero seconds within a 6-hour study visit
Proportion of Correct Responses in the Working Memory Task (N-back): Threat Condition - 1BACK - Run 1
Time Frame: 90 minutes plus 90 seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes plus 90 seconds within a 6-hour study visit
Proportion of Correct Responses in the Working Memory Task (N-back): Safe Condition - 1BACK - Run 2
Time Frame: 90 minutes plus 180 seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes plus 180 seconds within a 6-hour study visit
Proportion of Correct Responses in the Working Memory Task (N-back): Threat Condition - 1BACK - Run 2
Time Frame: 90 minutes plus 260 seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes plus 260 seconds within a 6-hour study visit
Proportion of Correct Responses in the Working Memory Task (N-back): Safe Condition - 3BACK - Run 1
Time Frame: 90 minutes post drug admin plus 45 seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes post drug admin plus 45 seconds within a 6-hour study visit
Proportion of Correct Responses in the Working Memory Task (N-back): Threat Condition - 3BACK - Run 1
Time Frame: 90 minutes plus 135 seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes plus 135 seconds within a 6-hour study visit
Proportion of Correct Responses in the Working Memory Task (N-back): Safe Condition - 3BACK - Run 2
Time Frame: 90 minutes plus 215 seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes plus 215 seconds within a 6-hour study visit
Proportion of Correct Responses in the Working Memory Task (N-back): Threat Condition - 3BACK - Run 2
Time Frame: 90 minutes plus 305 seconds within a 6-hour study visit
Stimuli were presented one at a time on a screen. Participants were instructed to remember (working memory) one or three stimuli back (N-back) from the current stimulus on the screen while undergoing alternating periods of safety and threat of shock i.e. while anticipating unpleasant electric shocks or no shock (safe). Two levels of difficulties were tested: 1- and 3-back. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Participants indicated whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task included 3 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block represented a given level of difficulty, i.e., 1- and 3-back. Performance on working memory task (n-back) accuracy was measured across condition (threat and safe) x Load (1-back, 3-back) using repeated measures ANOVA.
90 minutes plus 305 seconds within a 6-hour study visit
Reaction Time to Stimuli: Safe Condition - 1BACK - Run 1
Time Frame: 90 minutes post drug admin plus zero seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition( threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes post drug admin plus zero seconds within a 6-hour study visit
Reaction Time to Stimuli: Threat Condition - 1BACK - Run 1
Time Frame: 90 minutes plus 90 seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition (threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes plus 90 seconds within a 6-hour study visit
Reaction Time to Stimuli: Safe Condition - 1BACK - Run 2
Time Frame: 90 minutes plus 180 seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition (threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes plus 180 seconds within a 6-hour study visit
Reaction Time to Stimuli: Threat Condition - 1BACK - Run 2
Time Frame: 90 minutes plus 260 seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition (threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes plus 260 seconds within a 6-hour study visit
Reaction Time to Stimuli: Safe Condition - 3BACK - Run 1
Time Frame: 90 minutes post drug admin plus 45 seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition (threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes post drug admin plus 45 seconds within a 6-hour study visit
Reaction Time to Stimuli: Threat Condition - 3BACK - Run 1
Time Frame: 90 minutes plus 135 seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition (threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes plus 135 seconds within a 6-hour study visit
Reaction Time to Stimuli: Safe Condition - 3BACK - Run 2
Time Frame: 90 minutes plus 215 seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition (threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes plus 215 seconds within a 6-hour study visit
Reaction Time to Stimuli: Threat Condition - 3BACK - Run 2
Time Frame: 90 minutes plus 305 seconds within a 6-hour study visit
Reaction time (RT) is the time it takes to respond to stimuli. Participants RTs were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks (threat) or no shock (safe) during the n-back paradigm task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back. The task was organized in 2 runs, 8 blocks per run (4 safe and 4 threat presented alternatively), 18 sequential letters per block. Each block (threat or safe) corresponded to 2 tasks, 1- and 3-back tasks. RT was analyzed using condition (threat, safe) x Load (1Back, 3Back) repeated-measures ANOVA.
90 minutes plus 305 seconds within a 6-hour study visit
Measure of BOLD Response in Brain Clusters - Safe Condition - 1BACK
Time Frame: started 90 minutes post drug administration plus 90 seconds within a 6-hour study visit
The blood-oxygen-level dependent (BOLD) responses were measured using an fMRI scanner. The cerebral fMRI BOLD uses magnetic fields to measure localized changes in brain blood flow and blood oxygenation in activated regions-of-interest (ROI). Participants BOLD responses were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks or no shock (safe) during the n-back task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back.
started 90 minutes post drug administration plus 90 seconds within a 6-hour study visit
Measure of BOLD Response in Brain Cluster - Threat Condition - 1BACK
Time Frame: started 90 minutes post drug administration plus up to 360 seconds within a 6-hour study visit
The blood-oxygen-level dependent (BOLD) responses were measured using an fMRI scanner. The cerebral fMRI BOLD uses magnetic fields to measure localized changes in brain blood flow and blood oxygenation in activated regions-of-interest (ROI). Participants BOLD responses were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks or no shock (safe) during the n-back task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back.
started 90 minutes post drug administration plus up to 360 seconds within a 6-hour study visit
Measure of BOLD Response in Brain Clusters - Safe Condition - 3BACK
Time Frame: started 90 minutes post drug administration plus up to 270 seconds within a 6-hour study visit
The blood-oxygen-level dependent (BOLD) responses were measured using an fMRI scanner. The cerebral fMRI BOLD uses magnetic fields to measure localized changes in brain The blood-oxygen-level dependent (BOLD) responses were measured using an fMRI scanner. The cerebral fMRI BOLD uses magnetic fields to measure localized changes in brain blood flow and blood oxygenation in activated regions-of-interest (ROI). Participants BOLD responses were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks or no shock (safe) during the n-back task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back.
started 90 minutes post drug administration plus up to 270 seconds within a 6-hour study visit
Measure of BOLD Response in Brain Cluster - Threat Condition - 3BACK
Time Frame: started 90 minutes post drug administration plus up to 450 seconds within a 6-hour study visit
The blood-oxygen-level dependent (BOLD) responses were measured using an fMRI scanner. The cerebral fMRI BOLD uses magnetic fields to measure localized changes in brain blood flow and blood oxygenation in activated regions-of-interest (ROI). Participants BOLD responses were measured while undergoing alternating periods of safety and shock threat conditions i.e. while anticipating unpleasant electric shocks or no shock (safe) during the n-back task. The n-back is a paradigm used to assess working memory function by presenting sequential stimuli individually. Two levels of difficulties were tested: 1Back and 3Back (n-back). Participants were instructed to indicate whether the letter currently displayed was the same as the letter presented 1 or 3 letters back.
started 90 minutes post drug administration plus up to 450 seconds within a 6-hour study visit

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Measure of Level of Anxiety
Time Frame: 20 minutes after arrival for study; 80, 100, & 125 minutes post drug administration
The level of anxiety was assessed using the State Anxiety Inventory questionnaire. The State Anxiety Scale (S-Anxiety) evaluates the current state of anxiety. The State Anxiety Scale has 20 items. All items are rated on a 4-point scale ranging from "1 = not at all" to "4 = very much so". The scale has a minimum score of 20 and a maximum score of 80. Higher score indicates greater anxiety. State Anxiety score was measured at different time points during the study.
20 minutes after arrival for study; 80, 100, & 125 minutes post drug administration
Measure of Level of Anxiety
Time Frame: 20 minutes after arrival for study; 10 minutes & 145 minutes post drug administration
The level of anxiety was assessed using the State Anxiety Inventory questionnaire. The State Anxiety Scale (S-Anxiety) evaluates the current state of anxiety. The State Anxiety Scale has 20 items. All items are rated on a 4-point scale ranging from "1 = not at all" to "4 = very much so". The scale has a minimum score of 20 and a maximum score of 80. Higher score indicates greater anxiety. State Anxiety score was measured at different time points during the study.
20 minutes after arrival for study; 10 minutes & 145 minutes post drug administration
Measure of Heart Rate
Time Frame: 20 minutes after arrival for study; 80 minutes & 125 minutes post drug administration
The heart rate was monitored with two disposable electrodes on the ribcage midway between the waist and the armpit.
20 minutes after arrival for study; 80 minutes & 125 minutes post drug administration
Measure of Heart Rate
Time Frame: 20 minutes after arrival for study; 10 minutes & 145 minutes post drug administration
The heart rate was monitored with two disposable electrodes on the ribcage midway between the waist and the armpit.
20 minutes after arrival for study; 10 minutes & 145 minutes post drug administration

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Monique Ernst, M.D., National Institute of Mental Health (NIMH)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 16, 2014

Primary Completion (Actual)

October 7, 2021

Study Completion (Actual)

October 7, 2021

Study Registration Dates

First Submitted

May 31, 2014

First Submitted That Met QC Criteria

May 31, 2014

First Posted (Estimate)

June 3, 2014

Study Record Updates

Last Update Posted (Actual)

April 11, 2023

Last Update Submitted That Met QC Criteria

March 14, 2023

Last Verified

October 1, 2021

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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