Reference : UMR7291-ROCACK-001
Workplace : MARSEILLE 02
Date of publication : Friday, June 17, 2022
Scientific Responsible name : Rochelle ACKERLEY
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2022
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Decades of research have enabled significant innovations in peripheral nerve interfaces to restore sensation to the arms and hands of amputees. Mastectomy, another type of amputation, involves removal of breast tissue and often requires complete denervation of the chest wall. Despite the success of these surgeries in the treatment and prevention of cancer, the sensory consequences are severe, with many women experiencing sensory loss, chronic pain, and/or sexual dysfunction. Breast sensation plays a critical role in the daily lives of women, from the comfort of a hug to the awareness of one's shirt on the skin. Little is known about the neural basis of these sensations, and such a foundation of knowledge is necessary for the development of peripheral nerve interfaces to restore or preserve sensation to women undergoing mastectomy.
This project aims to address this gap by building an understanding of the neural underpinnings of tactile, affective, and erogenous touch on the breasts using: (i) psychophysical experiments to characterize sensation on the breasts, (ii) microneurography to monitor response properties of human afferent nerve fibres, and (iii) electrical stimulation of these same nerve fibres to evaluate the evoked artificial sensations. Psychophysical studies will include mapping tactile and affective sensations on the breasts and torso, including how these sensations differ with breast size, and age. Microneurography studies will allow us to characterize, for the first time, the response properties of peripheral nerves in the torso. In combination, the project links the responses in touch receptors with the perception of sensations. The overall aim of the collaboration – between Aix-Marseille University and the University of Chicago – is to characterize the neural coding and sensitivity of the breast, which lays the groundwork for restoring sensation in women who have had their breasts removed.
The thesis work will be performed at the Cognitive Neuroscience Laboratory (LNC, UMR7291, https://lnc.univ-amu.fr/en) at Aix-Marseille University under the supervision of Rochelle Ackerley (https://somatosense.fr/rochelleackerley), in collaboration with the groups of Sliman Bensmaia (https://bensmaialab.github.io) and Stacy Lindau (https://womanlab.org) at the University of Chicago, USA. The PhD student will be based at the LNC and funds come with the thesis for travel between France and the US. The PhD student will work in a team with researchers, engineers, post-docs, and other students. A microneurography room is installed at the LNC and additional facilities exist for behavioral work. Physiological and behavioral data sets will be collected, analyzed, interpreted, and presented at conferences and in scientific papers. He/she will be enrolled in the Doctoral School 62 Life and Health Sciences (https://ecole-doctorale-62.univ-amu.fr/en).
Constraints and risks
The thesis project consists of several sub-projects. Microneurography is a rare technique and takes time to learn, and data are not guaranteed. On the other hand, it enables recording of the activity of neurons in human peripheral nerve by the insertion of a small needle, and is thus uniquely valuable in advancing our understanding, not only of natural response patterns in human nerves, but also to the artificial sensations evoked by stimulation of these fibres. To avoid the risk of low yield of data, this project includes a full battery of psychophysical assessments to characterize sensation throughout the torso, as has been done in the hand – an undertaking that guarantees novel and necessary contributions to our understanding of sensation throughout the body.
The University of Chicago is developing the Bionic Breast Device, an implantable neuroprosthesis to restore touch sensation and reduce pain following mastectomy. Peripheral nerve stimulation has been shown to produce vivid tactile sensations and this will be tested at Aix-Marseille University for the stimulation of the intercostal nerves that innervate the breast. Dr. Ackerley's group has extensive experience characterizing the neural basis of pleasant and affective touch. Dr. Lindau's team has world renown expertise in female sexual function, including in breast cancer survivors. Dr. Bensmaia's team has expertise in discriminative touch and neuroprosthetics. The collaboration between these groups will allow for an unprecedented evaluation of the neural mechanisms that underlie the dynamic interplay between touch and breast sensation. A motivated and enthusiastic candidate is sought to work on this collaborative, interdisciplinary project, funded by the CNRS. A background in in neuroscience or a related subject (e.g. physiology, psychology, engineering, medicine) is required to perform physiological and behavioral experiments in humans and a good level of French and English is required. The PhD student will have the possibility to have secondments in Chicago.
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