Représentation du membre fantôme des amputés unilatéraux : une étude IRMf de la moelle épinière et du cerveau

Description

Context
Amputations of limbs are common with an estimated prevalence of 1.7 per 1000 in France for only the lower limb and this figure is set to increase. Besides problems with own-body image, most amputees suffer from phantom limb pain. The neural underpinnings of phantom pain, which relate to neural disruption at both the peripheral and central level, are not fully elucidated.
The objectives of the project are:
– First, to test a new rehabilitation method based on proprioceptive feedback relating to the missing limb, to alleviate phantom pain after amputation. The rationale is to stimulate peripheral sensory fibers and provide the brain with proprioceptive feedback normally associated with the actual movement of the missing limb.
– Second, to investigate peripheral and central underpinnings of PLP by correlating the beneficial impact of this promising rehabilitation method with changes in cortical representations evidenced by fMRI, and ii) by studying changes at the spinal cord level also by fMRI.
Methods
The project combines psychophysics, neuroimaging (fMRI, MR-spectroscopy, DTI) and clinical approaches.
– The effect of proprioceptive illusions using muscle tendon vibration to alleviate PLP in unilateral limb amputees will be tested during ten days of repeated stimulation treatment.
– The cerebral mechanisms responsible for the possible beneficial impact of the treatment will be investigated using fMRI and MR-spectroscopy performed before and after ten days of treatment, in amputees and in a healthy control group.
– Functional changes at the spinal cord level will be also assessed using an fMRI approach

Expected results
Activating residual muscle afferents from the stump and feeding the brain with more realistic proprioceptive feedback that simulates movements of the missing limb should restore appropriate spontaneous afferent firing, cortical organization and spinal sensorimotor circuits to finally alleviate phantom pain.

Profil recherché

The candidate will have a background in neurophysiology, statistics and programming skills (in Matlab/python). He/she will also have a keen interest for clinical perspectives and a real desire to interact with patients. Basic knowledge of fMRI will also be appreciated.

Établissement d'accueil

The student will be part of the Multisense and Body team at the Laboratory of Cognitive Neurosciences (campus Saint-Charles – Marseille). The team includes 8 permanent researchers, 7 PhD students and 3 post-doctorates. He/she will interact more closely with another PhD already working on the Phantom Pain project. The experiment will be conducted in two fMRI centres: the centre IRMf-INT at CERIMED and the CERMEP in Lyon.