Multisensory Body and Space Representations (BASES-EXTINCTION)

The acquisition of the surface EOG activity will be carried out by means of 3 surface electrodes, one of which, referred to as a reference, is placed on a bone zone (the glabella, above the nasion) and two others placed on The temples, coupled to an EOG amplifier.

In behavioral or transcranial stimulation protocols, surface EMG activity may be recorded for further analysis. No protocol included in this project will involve the recording of intramuscular electromyographic activity, which is invasive and involves the implantation of needle electrodes into the muscles.

The electrodermal response is a useful, simple and reproducible method for recording sweat gland activity that reflects autonomic nervous activity. Recordings will be made using traditional devices, including an amplifier (Delsys or BrainAMP or equivalent) as well as disposable electrodes.

The skin temperature will therefore be recorded during behavioral protocols using techniques for manipulating the representation of the body (perceptual illusion, prismatic deviation, etc.) using a specific measuring device.

Whatever the protocol, a diffusion tensor MRI (DTI) acquisition sequence as well as an image of the entire brain and high spatial resolution (T1 weight, 1x1x1 mm, nasion markers and pre-atrial points) will be acquired (Total duration: 20 minutes).

During the examination, the subject will have to perform tasks comparable to those described for the fMRI procedure, but with the additional possibility, offered by the MEG environment, of performing pointing or seizing of objects, provided that the Trunk and the subject's head be held in place by a suitable restraint system.

TMS is a non-invasive technique that uses very short (\ 100μs) magnetic pulses applied to the scalp to transiently and focally disrupt or improve the functioning of neuronal populations in the underlying superficial cortical regions.

The tDCS consists in passing a current of low intensity (generally ≤ 1mA to stimulate the cerebral cortex) between an anode and a cathode placed on the scalp, a part of this current crossing the tissues, and in particular the cortical regions situated between these two Electrodes. Generally, if the cathode is placed on the region of interest, it will be inhibited, while it will be energized if the anode is positioned thereon.