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Trial registered on ANZCTR
Registration number
ACTRN12624000943549
Ethics application status
Approved
Date submitted
21/06/2024
Date registered
5/08/2024
Date last updated
8/09/2024
Date data sharing statement initially provided
5/08/2024
Type of registration
Retrospectively registered
Titles & IDs
Public title
Pharmacology of human decision making - Study of the effects of ketamine on healthy volunteers (18-55) making simple perceptual decisions
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Scientific title
Pharmacology of human decision making (Phase 4 placebo-controlled ketamine hydrochloride study with healthy volunteers (18-55) targeting glutamatergic activity during perceptual decision making)
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Secondary ID [1]
311693
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Nil known
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Universal Trial Number (UTN)
U1111-1305-2231
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Trial acronym
PhD
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Linked study record
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Health condition
Health condition(s) or problem(s) studied:
Cognitive function
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Condition category
Condition code
Neurological
329854
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0
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Studies of the normal brain and nervous system
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Intervention/exposure
Study type
Interventional
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Description of intervention(s) / exposure
Ketamine injection - we will administer a single subcutaneous abdominal injection of ketamine hydrochloride, achieving a concentration of 0.7 mg/kg. As the intervention is a single injection, supervised by the study physician, no additional adherence monitoring is needed. There will be a one week washout period between active/placebo testing sessions.
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Intervention code [1]
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Treatment: Drugs
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Comparator / control treatment
In a placebo condition, participants will receive an abdominal injection, but this will be a saline solution of equivalent volume to the ketamine injection.
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Control group
Placebo
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Outcomes
Primary outcome [1]
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Accuracy on the decision task
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Assessment method [1]
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Accuracy will be recorded by the computerised task as whether the participant correctly identifies the direction of coherent motion on each trial.
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Timepoint [1]
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Accuracy will be recorded as participants complete the decision making task on each of the three testing sessions (baseline, active/placebo session 1, active/placebo session 2). The decision task, which will begin 10 minutes after administration, lasts 40 minutes.
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Primary outcome [2]
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Reaction times on the decision task
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Assessment method [2]
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Reaction times will be recorded by the computerised task as the interval between evidence onset (i.e. coherent motion) and the participant response on each trial.
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Timepoint [2]
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Reaction times will be recorded as participants complete the decision making task on each of the three testing sessions (baseline, active/placebo session 1, active/placebo session 2). The decision task, which will begin 10 minutes after administration, lasts 40 minutes.
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Primary outcome [3]
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Decision process dynamics
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Assessment method [3]
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Electroencephalograhic (EEG) signals linked to key stages of the decision process will be analysed to offer insight into the effects of glutamate challenge on decision formation. These signals include well-established neurophysiological signatures of evidence accumulation (centroparietal positivity), attention/task engagement (alpha oscillatory activity), decision urgency (contingent negative variation), and response preparation (desynchronisation of beta oscillatory activity). This is considered a composite outcome because each signal's dynamics must be considered in the context of the other signals to draw conclusions about the decision process.
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Timepoint [3]
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EEG will be recorded as participants complete the decision making task during each of the three testing sessions (baseline, active/placebo session 1, active/placebo session 2). The decision task, which will begin 10 minutes after administration, lasts 40 minutes.
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Secondary outcome [1]
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Depression
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Assessment method [1]
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Depression will be assessed with a number of online self-report questionnaires delivered through Qualtrics. The questionnaires will be analysed as a composite outcome to develop an profile of the participants experience of depression symptoms over the course of participation. There will be three types of questionnaire:
1) Baseline questionnaire - participants will complete a baseline questionnaire to establish baseline levels of depression. This will allow us to identify if any changes in psychological wellbeing detected over the course of the experiment were more/less pronounced based on these baseline scores. The questionnaire broadly target how the participant feels in general, rather than being specific to a narrow window of time. These measures include:
1a) The Beck Depression Inventory
1b) The Perceived Stress Scale
2) Pre-testing questionnaire - participants will complete a questionnaire before starting the decision task on each of the testing days. These questionnaires will monitor changes in their mood and wellbeing on a session-by-session basis, allowing us to isolate any effect of ketamine. These measures ask the participant to describe how they felt in the interval since the last testing session. These measures include:
2a) The Depression Anxiety Stress Scale 21
2b) The Patient Health Questionnaire 9
2c) The Clinical Outcomes in Routine Evaluation 10
3) Post-testing questionnaire - after participants have completed the task, they will complete a questionnaire, which repeats some of the pre-testing measures and includes some additional measures designed to assess the effect of ketamine on the participant. They will be used to assess the acute effects of ketamine. They include:
3a) The Positive and Negative Affect Schedule
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Timepoint [1]
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The baseline questionnaire will be completed at any time in advance of the baseline testing session. The pre- and post-testing questionnaires will be completed upon arrival (approx. 1 hour before starting the task) and immediately after completing the task on each of the testing days (baseline, active/placebo session 1, and active/placebo session 2). Participants will complete a final pre-testing questionnaire 1 week after participation in the final testing session.
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Secondary outcome [2]
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Anxiety
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Assessment method [2]
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Anxiety will be assessed with a number of online self-report questionnaires delivered through Qualtrics. The questionnaires will be analysed as a composite outcome to develop an profile of the participants experience of anxiety symptoms over the course of participation. There will be three types of questionnaire:
1) Baseline questionnaire - participants will complete a baseline questionnaire to establish baseline levels of anxiety. This will allow us to identify if any changes in psychological wellbeing detected over the course of the experiment were more/less pronounced based on these baseline scores. The questionnaire broadly target how the participant feels in general, rather than being specific to a narrow window of time. These measures include:
1a) The Brief Fear of Negative Evaluation Scale
1b) The Social Avoidance and Distress Scale
1c) The Perceived Stress Scale
2) Pre-testing questionnaire - participants will complete a questionnaire before starting the decision task on each of the testing days. These questionnaires will monitor changes in their mood and wellbeing on a session-by-session basis, allowing us to isolate any effect of ketamine. These measures ask the participant to describe how they felt in the interval since the last testing session. These measures include:
2a) The State-Trait Anxiety Inventory
2b) The Generalised Anxiety Disorder 7
2c) APA Severity Measure for Social Anxiety Disorder
2d) The Depression Anxiety Stress Scale 21
2e) The Clinical Outcomes in Routine Evaluation 10
3) Post-testing questionnaire - after participants have completed the task, they will complete a questionnaire, which repeats some of the pre-testing measures and includes some additional measures designed to assess the effect of ketamine on the participant. They will be used to assess the acute effects of ketamine. They include:
3a) The State-Trait Anxiety Inventory
3b) The Positive and Negative Affect Schedule
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Timepoint [2]
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The baseline questionnaire will be completed at any time in advance of the baseline testing session. The pre- and post-testing questionnaires will be completed upon arrival (approx. 1 hour before starting the task) and immediately after completing the task on each of the testing days (baseline, active/placebo session 1, and active/placebo session 2). Participants will complete a final pre-testing questionnaire 1 week after participation in the final testing session.
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Secondary outcome [3]
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Dissociation
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Assessment method [3]
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Dissociative symptoms will be assessed with a number of online self-report questionnaires delivered through Qualtrics. The questionnaires will be analysed as a composite outcome to develop a profile of the participants experience of dissociative symptoms over the course of participation. There will be three types of questionnaire:
1) Baseline questionnaire - participants will complete a baseline questionnaire to establish baseline levels of dissociative experiences. This will allow us to identify if any changes in psychological wellbeing detected over the course of the experiment were more/less pronounced based on these baseline scores. The questionnaire broadly targets how the participant feels in general, rather than being specific to a narrow window of time. These measures include:
1a) The Dissociative Experiences Scale II (dissociative symptoms)
2) Pre-testing questionnaire - participants will complete a questionnaire before starting the decision task on each of the testing days. These questionnaires will monitor changes in their mood and wellbeing on a session-by-session basis, allowing us to isolate any effect of ketamine. These measures ask the participant to describe how they felt in the interval since the last testing session. These measures include:
2a) The Cambridge Depersonalisation Scale - State Version
2b) The Clinician Administered Dissociative Symptoms Scale
3) Post-testing questionnaire - after participants have completed the task, they will complete a questionnaire, which repeats some of the pre-testing measures and includes some additional measures designed to assess the effect of ketamine on the participant. They will be used to assess the acute effects of ketamine. They include:
2a) The Cambridge Depersonalisation Scale - State Version
2b) The Clinician Administered Dissociative Symptoms Scale
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Timepoint [3]
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The baseline questionnaire will be completed at any time in advance of the baseline testing session. The pre- and post-testing questionnaires will be completed upon arrival (approx. 1 hour before starting the task) and immediately after completing the task on each of the testing days (baseline, active/placebo session 1, and active/placebo session 2). Participants will complete a final pre-testing questionnaire 1 week after participation in the final testing session.
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Secondary outcome [4]
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Obsessive-compulsive symptoms
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Assessment method [4]
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Obsessive-compulsive symptoms will be assessed with a number of online self-report questionnaires delivered through Qualtrics. The questionnaires will be analysed as a composite outcome to develop an profile of the participants experience of obsessive-compulsive symptoms over the course of participation. There will be two types of questionnaire:
1) Baseline questionnaire - participants will complete a baseline questionnaire to establish baseline levels of obsessive-compulsive symptoms. This will allow us to identify if any changes in psychological wellbeing detected over the course of the experiment were more/less pronounced based on these baseline scores. The questionnaire broadly target how the participant feels in general, rather than being specific to a narrow window of time. These measures include:
1a) The Vancouver Obsessional Compulsive Inventory
2) Pre-testing questionnaire - participants will complete a questionnaire before starting the decision task on each of the testing days. These questionnaires will monitor changes in their mood and wellbeing on a session-by-session basis, allowing us to isolate any effect of ketamine. These measures ask the participant to describe how they felt in the interval since the last testing session. These measures include:
2a) The Obsessive Compulsive Inventory Revised (OCD symptoms)
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Timepoint [4]
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The baseline questionnaire will be completed at any time in advance of the baseline testing session. The pre-testing questionnaires will be completed upon arrival (approx. 1 hour before starting the task) on each of the testing days (baseline, active/placebo session 1, and active/placebo session 2). Participants will complete a final pre-testing questionnaire 1 week after participation in the final testing session.
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Secondary outcome [5]
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Life satisfaction/general wellbeing
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Assessment method [5]
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Life satisfaction/general wellbeing will be assessed with online self-report questionnaires delivered through Qualtrics. The questionnaires will be analysed as a composite outcome to develop an profile of the participant's life satisfaction/general wellbeing over the course of participation.
1) Post-testing questionnaire - after participants have completed the task, they will complete a questionnaire, which repeats some of the pre-testing measures and includes some additional measures designed to assess the effect of ketamine on the participant. They will be used to assess the acute effects of ketamine. These measure include:
1a) The Subjective Happiness Scale
1b) The Personal Wellbeing Index Adult
1c) The Rosenberg Self-Esteem Scale
1d) The Compassion Motivation and Action Scales - Self
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Timepoint [5]
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The post-testing questionnaires will be completed immediately after completing the task on each of the testing days (baseline, active/placebo session 1, and active/placebo session 2).
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Secondary outcome [6]
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Fatigue
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Assessment method [6]
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fatigue will be assessed with online self-report questionnaires delivered through Qualtrics.
1) Pre-testing questionnaire - participants will complete a questionnaire before starting the decision task on each of the testing days. These measures include:
1a) The Karolinska Sleepiness Scale
2) Post-testing questionnaire - after participants have completed the task, they will complete a questionnaire, which repeats some of the pre-testing measures and includes some additional measures designed to assess the effect of ketamine on the participant. They will be used to assess the acute effects of ketamine. They include:
2a) The Karolinska Sleepiness Scale
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Timepoint [6]
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The pre- and post-testing questionnaires will be completed upon arrival (approx. 1 hour before starting the task) and immediately after completing the task on each of the testing days (baseline, active/placebo session 1, and active/placebo session 2).
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Eligibility
Key inclusion criteria
Aged 18-55
Right-handed
Normal or corrected-to-normal vision (glasses and contact lenses are ok)
No knowledge of any reason why they should not be given ketamine
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Minimum age
18
Years
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Maximum age
55
Years
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Sex
Both males and females
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Can healthy volunteers participate?
Yes
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Key exclusion criteria
Any cardiac conditions or history of high blood pressure
Assessed as having any contraindication to ketamine by our study physician
Assessed as suffering from a psychiatric disorder (according to DSM-V criteria) by our study physician
History of epilepsy
Females not on hormonal contraception
Pregnant or currently breastfeeding
Personal history of psychiatric or neurological illness
Family history of psychotic illness
Report any previous usage of antipsychotic or stimulant medication
History of significant* drug use
*'Significant' defined as (i) use of any illicit substances within the last 6 months; (ii) >5 lifetime intake of any illicit drug, except cannabis; (iii) more than monthly cannabis intake in the last 6 months
Current smoker or have smoked more than 5 cigarettes per week in their lifetime
Dependent on alcohol and consume more than 24 units/week
Currently taking any of the following substances: St. John's Wort, rifampin, grapefruit juice, clarithromycin
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Study design
Purpose of the study
Educational / counselling / training
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Allocation to intervention
Randomised controlled trial
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Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation to treatment schedules will be handled by a third party using a computerised randomisation script. That person will not involved in any stage of recruitment. The randomised schedule will be sent to the clinical pharmacy that prepare the doses, but will not seen by any member of the research team. The research team will remain blinded until the final participant has completed their last testing session.
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Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A randomisation code will be generated by a third-party using computer software and supplied to the clinical pharmacy supplying the doses. The code randomly assigns participants to one of two schedules (placebo -> active or active -> placebo) using their participant ID code. The code also ensures there is an even ratio of participants assigned to each schedule. The research team will only receive the randomisation code for analysis after data collection is complete.
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Masking / blinding
Blinded (masking used)
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Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
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Intervention assignment
Crossover
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Other design features
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Phase
Phase 4
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Type of endpoint/s
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Statistical methods / analysis
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Recruitment
Recruitment status
Recruiting
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Date of first participant enrolment
Anticipated
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Actual
14/06/2024
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Date of last participant enrolment
Anticipated
17/10/2024
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Actual
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Date of last data collection
Anticipated
31/10/2024
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Actual
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Sample size
Target
35
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Accrual to date
24
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Final
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Recruitment in Australia
Recruitment state(s)
VIC
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Funding & Sponsors
Funding source category [1]
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University
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Name [1]
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Monash University
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Address [1]
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Country [1]
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Australia
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Primary sponsor type
University
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Name
Monash University
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Address
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Country
Australia
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Secondary sponsor category [1]
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None
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Name [1]
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Address [1]
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Country [1]
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Ethics approval
Ethics application status
Approved
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Ethics committee name [1]
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Monash University Human Research Ethics Committee
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Ethics committee address [1]
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https://www.monash.edu/researchoffice/ethics
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Ethics committee country [1]
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Australia
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Date submitted for ethics approval [1]
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22/02/2024
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Approval date [1]
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28/02/2024
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Ethics approval number [1]
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37698
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Summary
Brief summary
Perceptual decision making is a fundamental cognitive process whereby sensory information is converted into meaningful perceptual interpretations of the environment for action. At a synaptic-level, the components of the decision process rely on a complex neuropharmacology, but the specific role of signalling pathways in supporting perceptual decisions is not well understood. Ketamine disrupts the brain's primary excitatory neurotransmitter, glutamate, by blocking glutamate receptors. This project will investigate the neuropharmacological basis of perceptual decisions by characterising the impact of glutamate challenge on key electrophysiological signatures of the decision process.
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Trial website
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Trial related presentations / publications
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Public notes
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Contacts
Principal investigator
Name
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Prof Mark Bellgrove
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Address
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School of Psychological Sciences, Monash University, Room 540, 18 Innovation Walk, Clayton Campus, Clayton, VIC 3800
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Country
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Australia
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Phone
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+61 3 9902 4200
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Fax
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Email
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[email protected]
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Contact person for public queries
Name
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Mark Bellgrove
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Address
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School of Psychological Sciences, Monash University, Room 540, 18 Innovation Walk, Clayton Campus, Clayton, VIC 3800
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Country
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Australia
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Phone
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+61 3 9902 4200
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Fax
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Email
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[email protected]
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Contact person for scientific queries
Name
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Mark Bellgrove
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Address
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School of Psychological Sciences, Monash University, Room 540, 18 Innovation Walk, Clayton Campus, Clayton, VIC 3800
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Country
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Australia
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Phone
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+61 3 9902 4200
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Fax
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Email
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[email protected]
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Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
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What data in particular will be shared?
De-identified behavioural and electrophysiological data
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When will data be available (start and end dates)?
The data will be uploaded to an open science repository as part of the publication process
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Available to whom?
Open science repositories are accessible to anyone
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Available for what types of analyses?
Access is not contingent on an analysis plan
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How or where can data be obtained?
The data will be accessible via the Open Science Framework (OSF; https://osf.io/).
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What supporting documents are/will be available?
No Supporting Document Provided
Results publications and other study-related documents
Documents added manually
No documents have been uploaded by study researchers.
Documents added automatically
No additional documents have been identified.
Download to PDF