fMRI Study of the Cerebal Bases of the Spatialization Process in Working Memory

Study Overview
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Brief Summary
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The present neuroimaging study investigates cerebral and behavioral markers of spatialization. Spatialization in memory corresponds to a mental representation of successive items from left to right in Westerners. A simple task to detect spatialization consists in presenting a series of stimuli sequentially. All stimuli are centered on the screen, so there is no spatial information during the task. After the presentation of the sequence, there is a recognition phase in which the participant is requested to take a decision as to whether a memory probe belongs to the sequence maintained in memory. The decision is made by pressing a key with the left or the right hand, depending on the instruction. The main measure is the difference in response times between the two hands. The standard spatialization effect in working memory in Westerners is that left-key responses are faster when retrieving the first items of the sequence whereas later items elicit faster right-key responses. To date, the factors that can influence this spatialization process in working memory as well as the brain structures involved remain largely unknown. Participants need to complete three experimental conditions associated with fMRI recording of brain activity. In task A (Visual Spatial), participants will see the sequences presented from left to right; in task B (Visual No Spatial), participants will see sequences of items presented in the middle of the screen; and in task C (Auditory), the sequences will be presented in an auditory format. When comparing tasks, A and B, we will be able to investigate if seeing information from left to right (spatialization is provided through the spatial coordinates of the items) is comparable to spatializing information from left to right (spatialization is not provided, all items have the same spatial coordinates). The comparison between task B and C will allow us to investigate the effect of seeing items (spatialization is not provided, all items have the same spatial coordinates) versus hearing them (spatialization is not provided and items have no spatial coordinates).

Official Title
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fMRI Study of the Cerebal Bases of the Spatialization Process in Working Memory in Young Healthy Adults

Conditions
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Healthy

Intervention / Treatment
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* Radiation: fMRI


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: right-handed adult subjects between 18 and 35 years of age, affiliated to or benefiting from a social security system having signed a prior informed consent. Exclusion Criteria: minors subjects aged 36 years and older, left-handed, neurological disorders contraindicating fMRI examinations, protected by law under guardianship or curatorship, or unable to participate in a clinical study under Article L. 1121-16 of the French Public Health Code.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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
Interventional Model Description: One group of young healthy adults. Participants need to complete three experimental conditions associated with fMRI recording of brain activity. In condition A (Visual Spatial), participants will see the sequences presented from left to right; in condition B (Visual No Spatial), participants will see sequences of items presented in the middle of the screen; and in condition C (Auditory), the sequences will be presented in an auditory format.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: young healthy adults<br>Participants need to complete three experimental conditions associated with fMRI recording of brain activity. In condition A (Visual Spatial), participants will see the sequences presented from left to right; in condition B (Visual No Spatial), participants will see sequences of items presented in the middle of the screen; and in condition C (Auditory), the sequences will be presented in an auditory format. | Radiation: fMRI<br>* The participant will then complete a series of working memory tasks under three distinct conditions as described above (visual spatial, visual non-spatial, auditory). The instructions and tasks will be administered via an MRI compatible monitor and headset system (NordicNeuroLab). During the tasks, the participant's brain activity will be recorded. Finally, at the end of the experiment, a high-resolution anatomical image of the brain will be acquired in order to facilitate the subsequent data processing steps and to define the position of the interparietal sulcus for each subject. The visit will be completed by a visual imaging questionnaire.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Behavioral measure | Reaction time (ms) across experimental conditions | during the fMRI | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Brain measure | Brain activity recorded using fMRI device across experimental conditions level of Blood-Oxygen-Level-Dependant (BOLD) effect | through study completion, an average of 2 years |