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.

Functional and structural cerebral changes in key brain regions after a facilitation programme for episodic future thought in relapsing-remitting multiple sclerosis patients

“…In particular, the hippocampus is involved in the extraction and binding of details associated with future events, but also in the encoding of the simulation product . As mentioned earlier, in MS patients, significant brain activation changes have been reported within the EFT core network when imagining personal future events, especially increased activations in the bilateral prefrontal regions (Ernst, Noblet, et al, 2015). In this same study, a positive association between the volume of the prefrontal region and the amount of details of future events has also been reported in MS patients.…”

“…In the case of RR-MS patients, the use of a high retrieval support condition led to a significant EFT improvement, as previously reported in non-amnesic conditions (McKinnon, Black, Miller, Moscovitch, & Levine, 2006;Svoboda et al, 2002). Furthermore, converging evidence were also obtained from neuroimaging findings, showing that EFT impairment in RR-MS patients were mainly associated with increased prefrontal activation changes and with the volume of prefrontal regions (Ernst, Noblet, et al, 2015).…”

“…While EFT involves a collection of different cognitive processes, visual imagery and executive functions contribute to a large extent to the generation of future events (D'Argembeau, Ortoleva, Jumentier, & Van der Linden, 2010). Based on this, the rationale of the MVI programme is to emphasise on the role and the use of visual imagery in the generation of future events to alleviate the one of executive functions, which is a driving mechanism of EFT impairment in MS patients (Ernst et al, 2014;Ernst, Noblet, et al, 2015). As such, the strategy taught to patients is to use mental visual cues to engage in the construction of future events and flesh them out with details.…”

Episodic Past, Future, and counterfactual thinking in Relapsing-Remitting Multiple sclerosis

“…To add to this evidence, recent studies have shown that RRMS patients also present parallel difficulties in EAM and EFT ( Ernst et al, 2014 , Ernst et al, 2015a ). As with EAM in RRMS, this impairment in EFT, too, has been associated with bilateral prefrontal and hippocampal hyperactivation ( Ernst et al, 2015b , Ernst et al, 2016 ). Such parallel impairments align with the finding that both EAM and EFT share common neurocognitive mechanisms ( Schacter et al, 2012 ).…”

Episodic foresight in multiple sclerosis.

“…1In two other studies (Ernst et al, 2015, 2016), the RRMS participants also contributed to the Ernst et al, (2014) dataset.…”