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Soutenance de thèse (Malek ABIDI)

Publié le 29 juin 2020 – Mis à jour le 2 juillet 2020

Étude Des Circuits Et Réseaux Neuronaux Engagés Dans La Préparation Et L’imagerie Motrice De La Locomotion Chez Des Patients Atteints De Sclérose Latérale Amyotrophique

Date(s)

le 20 décembre 2019

15h30
Lieu(x)

Bâtiment Alice Milliat (S)

Amphi S2
ALS with lower motor neurons (LMN) and ALS with upper motor neurons (UMN), we evaluated the functional adaptation in ALS patients during the preparation of self-initiated motor task. Decreased supplementary motor area (SMA) and dorsolateral prefrontal cortex activities and increased activities in subcortical regions were detected in UMN patients compared to controls and LMN during motor preparation. Increased effective connectivity of the striato-cerebellar circuit reinforcing weakened AMS-striatum and AMS-cerebellum circuits was also demonstrated. The loss of functional integrity of the planning sensorimotor network could lead to impaired motor imagery of locomotion in UMN patients. Therefore, in the second study, we tested this hypothesis by devising an fMRI paradigm involving locomotor imagery. Behavioral data showed a significant increase in imagery time in UMN patients compared to controls and LMN during precise postural gait. Functionally, in UMN patients, decreased SMA and the dorsolateral prefrontal cortex activities as well as additional recruitment of the parietal and cerebellar regions were recorded during imagined locomotion. Enhanced functional connectivity of the striato and parieto-cerebellar circuits reinforcing weakened connections of the premotor region was also demonstrated. Our findings indicate that, despite compensatory processes, the coexistence of circuits with decreased and increased connectivity suggests concomitant neurodegenerative and adaptive changes and could explain motor disorders observed in ALS.

 

Mis à jour le 02 juillet 2020