Simultaneous PET/MR Imaging of Human Brain Plasticity

Study Overview
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Brief Summary
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Background: Neuronal plasticity is the brain's ability to continuously adapt to experiences and learning of new skills. Although this affects multiple characteristics of the brain such as structure, function and metabolism, direct interactions between these aspects are largely missing. Aim: Using recent advancements in neuroimaging we aim to identify novel relationships how neuronal plasticity is related across these characteristics. Design: 40 healthy subjects will undergo two simultaneous PET/MR measurements at baseline and after 4 weeks. During the measurements a cognitively challenging task will be performed and the training group (20 subjects) will practice during the 4-week period. Implications: We combine simultaneous PET/MR and novel task-specific PET imaging to study brain metabolism, structure and function in a single measurement session. This provides optimal sensitivity for assessment of multimodal neuroplasticity associations. Knowledge how cognitive training affects multiple characteristics of the brain will also increase our understanding of disorders like depression, dementia and brain injuries, since these are diagnosed with cognitive evaluations. Considering the vast usage of the applied imaging procedures in diagnosis and therapy monitoring, the thorough investigation of multimodal associations offers benefit for the interpretability of neuroimaging in clinical routine.

Detailed Description
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Methodological details: Each subject will undergo two PET/MR examinations. Imaging will include PET as well as acquisition of structural and functional MRI. Task-specific glucose metabolism will be quantified with the radioligand [18F]FDG. Gray matter volume and white matter microstructure will be assessed with T1-weighted and diffusion weighted MRI, respectively. Functional imaging will focus on functional connectivity during rest and task as well as cerebral blood flow as acquired with ASL.

Official Title
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Multimodal Associations of Human Brain Plasticity Investigated With Simultaneous PET/MR Imaging

Conditions
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Neuronal Plasticity

Intervention / Treatment
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* Behavioral: Tetris


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age range 21-30 years Right-handedness Willingness and competence to sign the informed consent form Exclusion Criteria: History of or current physical, neurological or psychiatric disorder History of or current substance abuse or medication including antipsychotic, antidepressant and antianxiety agents Pregnancy or current breastfeeding Contraindications for MRI-scanning (e.g., metal implants, steel grafts, etc), including dental implants causing signal artifacts For subjects participating in earlier studies using ionizing radiation, the total radiation exposure of 30mSv over the last 10 years must not be exceeded, as specified in the Austrian legislation on radiation protection Regular players of the video game Tetris (3 years before scanning). Failure to comply with the study protocol or to follow the instructions of the investigating team

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Training<br>20 healthy participants, 4 week training of a challenging cognitive task (Tetris) between PET/MR measurements | Behavioral: Tetris<br>* The video game Tetris is a cognitively challenging task, which requires mental rotation, problem solving and fast visuo-spatial and motor coordination.<br>|
| No Intervention: Control<br>20 healthy participants, no training between PET/MR measurements | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Training induced changes in imaging parameters | Imaging parameters are glucose metabolism ([18F]FDG PET), cerebral blood flow (arterial spin labeling MRI), functional connectivity (resting-state and task fMRI), gray matter volume (T1-weighted MRI) and white matter structure (diffusion weighted MRI) | 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cognitive performance | Training induced changes in performance of the video game (score per minute) | 4 weeks |