Measure of Fatigue in Functional MRI
Condition: Fatigue
MeSH terms: Fatigue
Study type: Interventional

Summary: 
      The purpose of this study is to determine more objective, central and peripheral indices of
      fatigue state by exploring the neural and behavioral correlates of the alert process while
      keeping the idea to corroborate these results with those obtained during the performance of
      physical exercises and neuropsychological tests "classics" of attention, motivation, and
      functions evaluation. The interest of this study is to manipulate and compare the phasic and
      tonic alert mechanism through the activation of an extrinsic motivational system during
      fatigue. The investigators have chosen the alert since it is a basic cognitive process
      defined as the ability to increase attentional resources with the expectation of a target
      stimulus resulting in reduced response time. It can be phasic (extrinsic), favored by the
      presence of a warning signal preceding the target (preparation time) or tonic (intrinsic)
      occurring without warning signal (wakefulness). The evaluation of the alert is classically
      realized by a simple reaction time task with the presence or not of warning signal soliciting
      wether the tonic alert or the phasic alert.

      The investigators suppose to revisit the healthy population with brain model alert issued in
      2010 which highlighted the predominant role of the regions of the dorsolateral prefrontal
      cortex, parietal, cingulate and thalamus (non-motor) in maintaining attention and temporal
      preparation alert task.

      The investigators identify also functional, motor and cognitive components of basal ganglia
      of thalamus. Cognitive-motor paradigm and neurological dysfunctions observed in multiple
      sclerosis population will help to identify and separate the cognitive role and motor brain
      regions, particularly the thalamus and basal ganglia. New neurological hypotheses are
      proposed
    

Detailed description: 
      This project will be applied on healthy subjects, and the subject will be equipped with two
      electrodes attached to the muscle of the left arm (flexor) to measure muscle activity. That
      will be performed with a handgrip (the subject press on the handgrip).The subject will
      receive two sessions. It will conduct a trial session in the laboratory to control his
      ability to imagine the task (imagination run) and perform the driving task correctly.

      Two saliva samples will be placed in tubes to be analysed to measure the concentration of
      cortisol before and after functional MRI. Then, psychological and satisfaction questionnaires
      will be completed by volunteers.

      This protocol will then be adapted and transferred to multiple sclerosis population (in a
      second study), for which fatigue is one of the symptoms most commonly reported.
    

Intervention name(s): Volunteer with MRI
Intervention type(s): Procedure
Intervention description(s): functional MRI
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Fatigue; functional MRI