Neural correlates of episodic future thinking impairment in multiple sclerosis patients

Abstract

Background. Recent clinical investigations showed impaired episodic future thinking (EFT) abilities in multiple sclerosis (MS) patients. On these bases, the aim of the current study was to explore the structural and functional correlates of EFT impairment in nondepressed MS patients. Method. Twenty-one nondepressed MS patients and 20 matched healthy controls were assessed with the adapted Autobiographical Interview (AI), and patients were selected on the bases of an EFT impaired score criterion. The 41 participants underwent a functional magnetic resonance imaging (fMRI) session, distinguishing the construction and elaboration phases of the experimental EFT, and the categorical control tests. Structural images were also acquired. Results. During the EFT fMRI task, increased cerebral activations were observed in patients (relative to healthy controls) within the EFT core network. These neural changes were particularly important during the construction phase of future events and involved mostly the prefrontal region. This was accompanied by an increased neural response mostly in anterior, and also posterior, cerebral regions, in association with the amount of detail produced by patients. In parallel, structural measures corroborated a main positive association between the prefrontal regions’ volume and EFT performance. However, no association between the hippocampus and EFT performance was observed in patients, at both structural and functional levels. Conclusion. We have documented significant overlaps between the structural and functional underpinnings of EFT impairment, with a main role of the prefrontal region in its clinical expression in MS patients.

Keywords:

• Episodic future thinking
• Multiple sclerosis
• Functional magnetic resonance imaging
• Cognition
• Voxel based morphometry

We thank B. Levine for personal communication of the Autobiographical Interview (AI) to one of us (L.M.). We also thank B. Journault, C. Vinet-Gasse, and A. Botzung for helping with testing, V. Voltzenlogel for interrater reliability scoring, and N. Heider, S. Graves, F. Ernwein, A. Clerc-Renault, E. Montaut, and the Neuropsychologie Cognitive Clinique MA students for the transcriptions of the AI audio-recordings. We are grateful to the “Imagerie in Vivo” Platform (ICube laboratory), where the magnetic resonance imaging (MRI) sessions were conducted, the Clinical Investigation Centre (CIC) of Strasbourg University Hospitals, where patients and controls were examined, and C. Marrer for MRI technical assistance.

Additional information

Funding

We are grateful to the “Fondation pour la Recherche sur la Sclérose en Plaques” (ARSEP; Ile de France; grant to L.M.) for research funding and to the Ministry of National Education and Research (A.E.’s PhD grant).

Notes on contributors

Alexandra Ernst

A.E. is now a postdoctoral researcher in the LEAD (CNRS UMR5022) at the University of Burgundy, supported by a research funding from the Region Bourgogne (France) accorded to Chris Moulin and Céline Souchay (LEAD, CNRS UMR5022, University of Burgundy).