The brain is composed of a set of areas specialized in specific computations whose outputs need to be transferred to other specialized areas for cognition to emerge. To account for context-dependent behaviors, the information must be flexibly routed through the fixed anatomy of the brain. The aim of this project is to test a general framework for this flexible communication between brain areas based on nested oscillations. The general idea is that internally-driven slow oscillations (<20Hertz) either set-up or prevent the communication between brain areas. Stimulus-driven gamma oscillations (>30Hertz), nested in the slow oscillations, can then be directed to task-relevant areas of the network. This multimodal, multi-scale approach uses magnetoencephalography using a 3-Dimensional (3D) printed individual head-cast system and transcranial stimulation in experiments manipulating visual processing, attention and memory to test core predictions of this framework. The theoretical approach and the methodological development used in this basic science study will provide the basis for future fundamental and clinical research.

Inclusion Criteria:

• 20-36 years old
• Right handed
• Registered with the French healthcare system
• Motivated to participate in the study
• Normal or corrected vision
• Adequate knowledge of French to be able to follow directions and give informed consent
• Capacity to listen and follow study instructions
• Use of contraception (in sexually active women)
• BMI between 18.5 and 30
• Informed consent for participation in the study

Exclusion Criteria:

• For All Experiments:

• Persons with :

  • Sleep disorders, neurological or psychiatric illnesses or a history of such problems that could impact quality/variability of data or cooperation and retention of the subject in the study
  • Migraines or light-sensitive epilepsy
  • Regular use of medications that impact the central nervous system
  • Regular use of medications, such as opioids and antidepressants, including Selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants
  • Severe hearing loss
  • Skin conditions or allergies
  • Chronic pain, or any other medical conditions conducive to pain sensitivity
  • A history of stroke or recent trauma to the head
  • A pacemaker, insulin or other pump, neurostimulator, cochlear implants or other hearing aid, metal stents, prosthesis, or implants, intracerebral clips, implantable defibrillator, cerebral shunt or ventricular catheter, other foreign metal objects in the upper part of the body

• Persons unable to adhere to abstinence from the use of drugs or alcohol the day or evening before experimental sessions

• Women who are pregnant, breastfeeding, or have given birth in the last 6 months

For experiments using magnetoencephalography:

• Persons with

  • claustrophobia
  • any dental apparatus containing metal including or root canals
  • any foreign metallic object anywhere in the body
  • bolts, screws
  • orthopedic devices or implants
  • glasses (given the participant cannot use contact lenses)
  • a head size incompatible with the use of a personalized 3D head-cast or a magnetoencephalograph

• Persons having had any surgery prior to the study which puts them at risk for metal objects left in the body

For experiments using Magnetic Resonance Imaging (MRI) or Functional Magnetic Resonance Imaging (fMRI) techniques:

• Anxious, non-cooperative, or agitated persons
• Claustrophobia
• Persons having had any surgery prior to the study which puts them at risk for metal objects left in the body

For experiments using transcranial stimulation:

-Persons with frequent syncope episodes (loss of consciousness) as a result of any particular sensorial stimulations