Job ID: 118107

PhD project: Understanding the role of sensorimotor representation in dyslexia: neural basis and impact of comorbidity

Position: Ph.D. Student

Deadline: 14 April 2024

Employment Start Date: 1 October 2024

Contract Length: 3 years

City: Marseille

Country: France

Institution: Aix Marseille Université

Department: CRPN and CRMBM laboratories

Description:

The NeuroSchool PhD Program of Aix-Marseille University (France) has launched its annual calls for PhD contracts for students with a master’s degree in a non-French university. This project is one of the 13 proposed projects. Not all proposed projects will be funded, check our website for details.

State of art: The first attempt at integrating phonological and sensorimotor hypotheses of dyslexia in a unified framework yielded successful results in young adults with dyslexia, with sensorimotor impairment affecting phonemic and articulatory performances, as well as mental action representations (Marchetti et al., 2022; 2023). Interestingly, behavioural studies also highlighted an increased proportion of sensorimotor impairment in young adults with dyslexia (27%) compared to control readers (5%), further substantiating the link between deficits in phonemic representation and impaired articulatory and bodily actions internal representations, specific to the dyslexic subgroup with sensorimotor impairments.

Objectives: This PhD project aims to investigate the neural basis of the functional links between language and sensorimotor representations impairment in dyslexia. With a set of fMRI studies, this study will determine whether sensorimotor representation deficits are devoted to a particular sub-group of dyslexic adults (domain-specific, dependent of dyslexia) or devoted to more global sensorimotor impairments (domain-general, independent of dyslexia).

Expected results: We will investigate whether dyslexic deficits are underpinned by associated brain features in the networks devoted to internal representation of action and learning (i.e., fronto-parietal, cingulo-opercular, somato-motor and cerebellar-cortical networks), speech articulation (i.e., left posterior IFG, left anterior insula, left sensorimotor cortex, and right inferior cerebellum), skilled reading, including phonological processing (left fronto-temporo-parietal regions, planum temporale, and precentral gyrus) and visual-orthographic processing (left occipito-temporal regions), as well as the connection between the inferior parietal lobule and the visual word form area (VWFA), which was recently reported as a plausible marker for dyslexia. We propose a set of 3 MRI studies, using 7T ultra-high field (UHF) MRI, including structural and functional resting state investigations, along with two fMRI protocols of bodily and articulatory representations to unify sensorimotor and phonological hypotheses of dyslexia.

Feasibility: To address these questions, a comparative study of four groups is required: Dyslexic Adults (DA) without sensorimotor comorbidity; Dyslexic Adults with sensorimotor comorbidity (DAC); Skilled readers with sensorimotor deficit, called developmental coordination disorder (DCD); Skilled readers without sensorimotor deficit (SR), as controls. The total cohort will include 100 students (19 – 24 years), recruited from the Aix-Marseille university. The CNRS has agreed to promote this project. Ethical approval was obtained in December 2022 for a 5-year period (N°SI: 22.03910.000124). The first 7T MRI pilot acquisitions were performed in spring 2023, and the fMRI protocols were successfully tested. MRI acquisitions will benefit from previous funding of NeuroMarseille and ILSB that secure half of the project. Other funding applications are in progress.

Complementarity of the two co-supervisors: This PhD project results from an association between two scientists from NEUROMARSEILLE, specialized in cognitive neurosciences and neurodevelopmental deficits (Ch. Assaiante) and in magnetic resonance imaging and clinical expertise (JP. Ranjeva), located in the same place and used to collaborating.

Expected candidate profile: Ideally, candidates should have experience in 7T MRI acquisition, processing, analysis, and interpretation, along with proficiency in statistical analysis (MATLAB, Python, or R). Previous experience in designing and conducting experimental studies, especially with clinical populations, is necessary. Excellent interpersonal and communication skills are required. A solid understanding of cognitive theories linked to the project is desirable.