An interventional study of Functional brain imaging without any contrast agent in Healthy Volunteers, sponsored by Hospices Civils de Lyon. Completed at 1 site in France. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-09-03.
Sponsored by Hospices Civils de Lyon · Not applicable, Interventional, and Basic science
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.
Exclusion Criteria:
Additional exclusion criteria for an fMRI recording
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
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).
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.
Time frame: 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.
Time frame: up to 1 week after the end of the encoding session
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.
Time frame: up to 1 week after the end of the encoding session
Plan to share: Undecided
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Hospices Civils de Lyon