Evaluation of the Impact of Laterality on Cerebral Activation During a Motor Task of the Upper Limb in Healthy Subjects
Condition: Healthy
Study type: Interventional

Summary: 
      The aim of this study is to investigate the differences in brain activation in healthy
      subjects during motor tasks, depending on the laterality of the subject, the laterality of
      the task and the complexity of the task. It seems that the laterality of activation is less
      marked in left-handed people, when using the non-dominant hand and when performing a complex
      task. The objective of this study is to highlight profiles of subject and modality of use of
      the hand with a specific lateralization of cerebral activation.
    

Detailed description: 
      Stroke frequently leads to upper limb deficit. The recovery of motor skills depends on many
      factors including laterality. The literature shows that cerebral activation during motor
      tasks differs depending on whether one is right-handed or left-handed and whether one uses
      the dominant hand or not. These differences probably lead to different recovery mechanisms
      depending on the side of the lesion and the laterality. An imaging technique is particularly
      suitable for exploring these different mechanisms: fNIRS (Functional Near Infra Red
      Spectroscopy). This method allows (like fMRI) to study cerebral neurovascular coupling. It is
      based on the fact that an activated brain region increases its local blood flow. Oxygenated
      (HbO) and deoxygenated (HbR) hemoglobin absorb infrared light and it is then possible to
      identify the cerebral cortical regions involved in a given task. This technique therefore
      makes it possible to study cerebral activation under more ecological conditions than fMRI and
      is thus particularly suitable for exploring rehabilitation techniques.

      This research aims to study and compare in healthy subjects, using an fNIRS apparatus, the
      brain regions involved in the performance of different motor tasks according to the
      laterality of the task and the subject.

      The investigations will be carried out by the principal investigator or by specialized
      technicians from the neurology functional exploration department.

      Stroke frequently leads to upper limb deficit. The recovery of motor skills depends on many
      factors including laterality. The literature shows that cerebral activation during motor
      tasks differs depending on whether one is right-handed or left-handed and whether one uses
      the dominant hand or not. These differences probably lead to different recovery mechanisms
      depending on the side of the lesion and the laterality. An imaging technique is particularly
      suitable for exploring these different mechanisms: fNIRS (Functional Near Infra Red
      Spectroscopy). This method allows (like fMRI) to study cerebral neurovascular coupling. It is
      based on the fact that an activated brain region increases its local blood flow. Oxygenated
      (HbO) and deoxygenated (HbR) hemoglobin absorb infrared light and it is then possible to
      identify the cerebral cortical regions involved in a given task. This technique therefore
      makes it possible to study cerebral activation under more ecological conditions than fMRI and
      is thus particularly suitable for exploring rehabilitation techniques.

      This research aims to study and compare in healthy subjects, using an fNIRS apparatus, the
      brain regions involved in the performance of different motor tasks according to the
      laterality of the task and the subject.

      The investigations will be carried out by the principal investigator or by specialized
      technicians from the neurology functional exploration department.

      The acquisition has a duration of 25 minutes, it begins with a rest period of 120 seconds,
      which corresponds to the baseline. Four different tasks are performed during the acquisition
      for each subject:

        -  Simple task right hand (SD)

        -  Simple task left hand (SG)

        -  Complex task right hand (CD)

        -  Complex stain left hand (CG)

      The design is a block design, each task, which has a duration of 20 seconds, is carried out 8
      times per acquisition. There is therefore a total of 32 tasks whose order will be randomized.

      For simple tasks, movements are performed at a frequency of 0.5 Hz which appears to be the
      optimal frequency for observing cortical activation using a metronome.

      Between periods of movement, the subject is in a rest position for a period from 15 to 25
      seconds.

      Instructions are given verbally at the start of each phase. After recruiting the subjects,
      the study investigator will check the inclusion and exclusion criteria.

      If the subject can integrate the protocol, the acquisition will then be planned.

      On the day of the acquisition, the fNIRS acquisition helmet (Brite MKII) will be installed by
      a specialist technician and instructions will be given. The recording is then made.
    

Intervention name(s): Simple task; complex task
Intervention type(s): Behavioral; Behavioral
Intervention description(s): The subject is seated on a chair facing a table, both hands resting on the table.
The subject is asked, for each block of 20 seconds, to perform flexion / extension movements of the fingers of the left hand at 0.5 Hz.; The subject is seated on a chair facing a table, both hands resting on the table.
The subject is asked, for each block of 20 seconds, to perform an exercise based on the nine hole peg test
Intervention model: Single Group Assignment
Intervention model description: 60 healthy subjects (30 left handed and 30 right handed) will be recruited and will carry out the acquisition.
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Laterality; motor task; cerebral activation; near infrared spectroscopy