Effect of Transcutaneous Auricular Stimulation of the Vagus Nerve on Functional Connectivity in the Brain at Rest

Effect of Transcutaneous Auricular Stimulation of the Vagus Nerve on Functional Connectivity in the Brain at Rest: fNIRS Study in Chronic Post-stroke Subjects and Healthy Subjects

The goal of this clinical trial is to study the effect of Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) on resting-state brain functional connectivity. The study will assess this effect using functional Near-Infrared Spectroscopy (fNIRS) in both chronic post-stroke patients and healthy subjects.

The main questions it aims to answer are:

Does taVNS affect resting-state functional connectivity (measured by fNIRS) in chronic post-stroke patients?

Does taVNS affect resting-state functional connectivity (measured by fNIRS) in healthy subjects?

Are there differences in the effect of taVNS on functional connectivity between the post-stroke group and the healthy group?

Researchers will compare the effect of active taVNS (real stimulation) to a sham stimulation (control) to evaluate its specific impact on the brain's functional networks.

Inclusion Criteria for post-stroke participant:

• age 18 or older
• Right-handed participant;
• Hemiparesis in the chronic phase (>6 months post-stroke)
• Participant who has agreed to sign an informed consent form;
• Participant who is affiliated with social security.

Inclusion Criteria for healthy participant:

• age 18 or older
• Right-handed participant;
• Participant who has agreed to sign an informed consent form;
• Participant who is affiliated with social security.

Exclusion Criteria for post-stroke participant:

• Allergy to neoprene (the material used to make the fNIRS cap);
• Hair volume preventing the cap from being put on and/or access to the scalp;
• Cognitive impairment making it impossible to participate in the study;
• Phasic disorders preventing understanding of instructions and effective communication;
• Pregnant or breastfeeding women;
• Persons under legal protection

Exclusion Criteria for post-stroke participant:

• Allergy to neoprene (the material used to make the fNIRS cap);
• Hair volume preventing the cap from being put on and/or access to the scalp;
• Pregnant or breastfeeding women;
• Persons under legal protection