HIERARCHY OF VISION

Not Applicable

Withdrawn

• Conditions: Neurologic Signs
• Interventions: Device: functional Magnetic Resonance Imaging

• Registration Number: NCT03905616
• Lead Sponsor: Hospices Civils de Lyon

Brief Summary

Little is known about the exact role of feedback in cortical processing. Hypotheses on its function range from attentional control to the transmission of Bayesian priors in the interpretation of sensory events, such as in the theory of Predictive Coding. Recent advances in identification of functional signatures of feedback and feedforward signal, as well as additional techniques based on causal relations in signal processing open a unique methodology for probing such processes in awake and behaving organisms and testing these theories and more generally the hierarchical processing between cortical areas.

The objective of this project is to study feedback and feedforward relations and localization in the well established pathways between cortical areas V1 and Medial Temporal (MT) that have been implicated in early integration processes in motion perception.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2019-04-04
• Study First Submitted QC: 2019-04-04
• Study First Posted: 2019-04-05
• Study Start: 2019-07-22
• Status Verified: 2021-02
• Primary Completion: 2021-02-17
• Study Completion: 2021-02-17
• Last Update Submitted: 2021-02-23
• Last Update Posted: 2021-02-25

Recruitment & Eligibility

• Status: WITHDRAWN
• Sex: All
• Target Recruitment: Not specified

Inclusion Criteria

• Aged between 18 and 40 years old
• Affiliated to a social security scheme
• Be right-handed
• Have signed the informed consent

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Exclusion Criteria

• Subjects with a neurological or psychiatric history
• Subjects with visual disturbances not corrected
• Pregnant, lactating or childbearing women without contraception.
• Persons under guardianship, trusteeship or any other administrative or judicial measure of deprivation of rights or liberty, as well as adults protected by law.
• Participants refusing to be informed of the results of the medical examination.
• Participants refusing to be informed of the possible detection of an anomaly.
• Volunteers with contraindications to the MRI examination: people using a pacemaker or an insulin pump, persons wearing a metal prosthesis or an intracerebral clip as well as claustrophobic subjects, neurosensory stimulator or implantable defibrillator, cochlear implants, ferromagnetic foreign body ocular or cerebral close to the nerve structures, agitation of the subject (non-cooperating or agitated subjects), ventriculoperitoneal neurosurgical bypass valves, dental apparatus.

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
healthy subjects	functional Magnetic Resonance Imaging	25 healthy subjects with a normal/corrected vision fitting to all of the inclusion/exclusion criteria. All the subjects will be tested on the same visual stimuli, leading to intrasubject comparison analyses of functional magnetic resonance imaging (fMRI) activity between conditions.

Primary Outcome Measures

Name	Time	Method
Non-invasive Blood oxygenation level dependent (BOLD) fMRI activity	At inclusion	Blood oxygenation level dependent (BOLD) imaging is the standard technique used to generate images in fMRI studies, and relies on regional differences in cerebral blood flow to delineate regional activity. This non-invasive technic is not inducing any particular risk. The non invasive BOLD fMRI activity will be recorded in healthy subjects during a task of visual perception.