A New Generation of Magnetoencephalographs for High Speed Functional Brain Imaging

The goal is to perform a first evaluation of the capabilities of a new generation of non-invasive magnetoencephalography whole head device using optically pumped magnetometers using Helium 4 as the sensitive element (OPM He4) to record brain magnetic activities. The investigators will record 1) healthy subjects stimulated with visual, auditory, somesthesic and motor stimuli and 2) athletes who suffered a mild concussion. The main hypothesis is that the OPM magnetoencephalographs (MEG) system will be able to detect brain activity. The secondary hypothesis is that the data recorded with the OPM MEG system will allow to reconstruct maps of the brain activity. To test the main hypothesis, they will compare the signal to noise ratio of brain activities between a classical MEG system and the new OPM He4 MEG. The secondary hypothesis will be tested through a comparison of the maps of brain activity obtained thanks to the data recorded with a classical MEG system and the new OPM He4 MEG.


Eligibility Criteria:
Healthy volunteers:

Inclusion Criteria:

* Age 18 to 70
* Strongly motivated to participate to the study
* Signed informed consent for the study

Exclusion Criteria:

* major cognitive deficit and unable to understand the instructions
* previous neurology or psychiatric or sleep pathologies
* Woman with a positive pregnancy test during the inclusion.
* Subjects under guardianship, curatorship or safeguard of justice protection
* Subjects deprived of their liberty
* Subject not affiliated to a social security system.
* Subject with common contraindications to MEG and MRI examination :

  * Metal in the body incompatible with performance of the examination (pacemaker, implantable pump, neurostimulator, cochlear implant, auditory prothesis, metalic prothesis, intracerebral clip, implantable defibrillator, any metalic parts in the brain or upper part of the body, ventriculoperitoneal valve, dental appliance or steel pivot for root canal, ferromagnetic foreign body in the upper part of the upper part of the body)
  * Claustrophobia

Subjects who suffered a mild concussion:

Inclusion Criteria:

* Male aged from 18 to 40
* Strongly motivated to participate to the study
* Signed informed consent for the study
* Mild concussion confirmed by the club doctor and a neurologist neurologist in the three weeks preceding the experiment

Exclusion Criteria:

* major cognitive deficit and unability to understand the instructions
* previous neurology or psychiatric or sleep pathologies except mild concussion
* Woman with a positive pregnancy test during the inclusion.
* Subjects under guardianship, curatorship or safeguard of justice protection
* Subjects deprived of their liberty
* Subject not affiliated to a social security system
* Subject with common contraindications to MEG and MRI examination :

  * Metal in the body incompatible with performance of the examination (pacemaker, implantable pump, neurostimulator, cochlear implant, auditory prothesis, metalic prothesis, intracerebral clip, implantable defibrillator, any metalic parts in the brain or upper part of the body, ventriculoperitoneal valve, dental appliance or steel pivot for root canal, ferromagnetic foreign body in the upper part of the upper part of the body)
  * Claustrophobia