Contextual Associations During Episodic Recall of Everyday or Virtual Reality

Study Overview
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Brief Summary
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The project is dedicated to development of new paradigms to investigate memory and attention in the rich and realistic environments. The investigator will use modern interactive digital technologies for encoding complex episodes either using mobile phone technology in everyday life or using a virtual reality life-like simulation. He aims to characterize the role of the medial temporal lobe and prefrontal cortex during recall of naturalistic episodic experiences, using functional neuroimaging (fMRI) in healthy participants. The secondary aim is assess how the allocation of attention during memory encoding contribute to mechanisms of the subsequent recall. He will achieve this by monitoring gaze direction during encoding and by analyzing the retrieval data as a function of the elements that participants attended / fixated during encoding. The protocol will involve, first, behavioral testing of memory performance with encoding in the real-life or in virtual reality, followed by the main hypothesis testing phase when fMRI will be used to measure brain activity during retrieval.

Official Title
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Contextual Associations During Episodic Recall of Everyday or Virtual Reality

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Other: Functional brain imaging without any contrast agent


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Possession a Smartphone compatible with GPS 3-rd generation and exploitation system Android 4.2 with user-activated geolocation (for mobile phone studies). Able to navigate in virtual reality with a help of the keyboard (for virtual reality studies). Not using glasses. All subjects will give their written consent for participation in the study. They will be right-handed They will have French social coverage. Exclusion Criteria: Previous neurologic or psychiatric disease. Cognitive deficits restricting understanding of the tasks. Pregnant or breath-feeding women. Persons under guardianship, curatorship or any other administrative or judicial measure of deprivation of rights or liberty. Subjects currently participating in other study. Additional exclusion criteria for an fMRI recording Neurologic, cardiac electrostimulation or defibrillator. Cardiac prostheses Intracranial clips or clamps Cerebrospinal fluid disorders Metal particles in the eyes Metal dental or articular prostheses Diffusion pomp or other infusion system Claustrophobia Head tattoo , makeup, hair gel

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Memory for naturalistic episodes<br>Encoding of episode in real life situations (using Smartphones) or in a virtual environment, followed by memory retrieval (either behavior only or with fMRI, in successive studies) | Other: Functional brain imaging without any contrast agent<br>* During the fMRI protocol, the subject will perform the retrieval tasks while whole-brain activity will be recorded using Echo Planar Imaging (EPI) that measures the Blood Oxygen Level Dependent (BOLD) signal (2x2x2 isotropic voxels, Echo Time (TE) = 30 ms, Repetition Time (TR) = 2.5 sec). The functional session will be subdivided into several parts (Runs, duration: 10-15 min). Together with the functional data, the protocol will include a structural scan (T1 weighted, 1x1x1 mm voxels; duration 5-7 min) and a field mapping sequence (duration: 1 min).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| BOLD cerebral response to contextual recall in medial temporal lobe | After spatial preprocessing of individual series of EPI fMRI images, normalization and smoothing as suggested for SPM analysis, the successful and failed contextual recall will be modeled and convolved with canonical HRF function. The GLM will be estimated according to the algorithm of SPM, the significance threshold will be p<0.05 FWE within the regions of interest. Our hypothesis will be confirmed by activation of medial temporal lobe and prefrontal cortex in contextual recall, congruent contextual cueing and recall of episodes when targets were semantically congruent with the context at encoding. | up to 1 week after the end of the encoding session | 
| BOLD cerebral response to contextual recall in prefrontal cortex | After spatial preprocessing of individual series of EPI fMRI images, normalization and smoothing as suggested for Statistical Parametric Mapping (SPM) analysis, the successful and failed contextual recall will be modeled and convolved with canonical HRF function. The GLM will be estimated according to the algorithm of SPM, the significance threshold will be p<0.05 Family-wise error (FWE) within the regions of interest. Our hypothesis will be confirmed by activation of medial temporal lobe and prefrontal cortex in contextual recall, congruent contextual cueing and recall of episodes when targets were semantically congruent with the context at encoding. | up to 1 week after the end of the encoding session | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pattern of gaze fixation during episodic encoding and cerebral activity during recall | The gaze direction during both during episodic encoding and recall. We will estimate a correlation between the activation of medial temporal lobe/ prefrontal cortex and the similarity of the gaze fixations during encoding and retrieval. A positive correlation will support our hypothesis about the link between attention and contextual encoding. | up to 1 week after the end of the encoding session | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Memory, naturalistic, context, fMRI, Attention