Functional cerebral changes in multiple sclerosis patients during an autobiographical memory test.

Our aim was to investigate the functional underpinnings of autobiographical memory (AM) impairment in multiple sclerosis (MS) patients. To that end, 18 patients and 18 controls underwent the autobiographical interview (AI). Subsequently, the 36 participants underwent a functional magnetic resonance imaging (fMRI) session designed to assess the construction and elaboration of AMs. A categorical control task was also presented. Patients were trained in the fMRI procedure to optimise the procedural aspects accompanying the task itself. Although the patients obtained significantly poorer AI scores (p < .001), their performance on the easier AM fMRI task was efficiently carried out, allowing relevant comparisons with healthy controls. Relatively to healthy controls, the patients showed increased and bilateral cerebral activations (p < .005) during the construction and elaboration phases. The prefrontal, temporal and posterior cerebral region activations were located within the core network sustaining AM, with the bilateral prefrontal region being centrally involved. The parametric neural responses to the difficulty of access and amount of details of memories were also significantly different for the two groups, with the right hippocampal region showing a particularly increased recruitment (p < .005). The findings suggested the presence of functional cerebral changes during AM performance and supported the presence of AM retrieval deficit in MS patients.journal articleresearch support, non-u.s. gov't20152014 09 22importe

The Impact of Multiple Sclerosis on Future- Oriented Mental Time Travel - Neuropsychological and Neuroimagining Approaches

peer reviewe

FMRI contributions to addressing autobiographical memory impairment in temporal lobe pathology

Episodic autobiographical memory (AM) allows one, through the recollection of sensory-perceptual details, thoughts and feelings, to become aware of an event as belonging to one's own past as well as being able to project into one's future. Because AM provides a sense of self-continuity, contributes to the integrity of the self, and helps predicting future experiences, any deficit of AM may have debilitating consequences for everyday life functioning. Understanding AM failure and the underlying neural mechanisms has the potential to shed light on brain reorganization mechanisms and engagement of compensatory processes. Functional magnetic resonance imaging (fMRI) provides the most promising imaging method to tackle these issues. We reviewed evidence from the few studies that used fMRI to investigate the functionality of the residual tissue, the neural reorganization and compensatory mechanisms in patients with neurological conditions due to impaired medial temporal lobe. Overall, these studies highlight the importance of the left hippocampus, which when atrophied and not functional leads to AM deficits but its residual functionality may support relatively normal AM recollection. When damaged hippocampal tissue is not functional, other brain regions (e.g., the medial prefrontal cortex) may be involved to compensate impairment, but they appear generally ineffective to support detailed episodic recollection

Using mental visual imagery to improve autobiographical memory and episodic future thinking in relapsing-remitting multiple sclerosis patients: a randomised-controlled trial study

PURPOSE: The co-occurrence of autobiographical memory (AM) and episodic future thinking (EFT) impairment has been documented in relapsing-remitting multiple sclerosis (RR-MS) patients. On these bases, we aimed at probing the efficacy of a mental visual imagery (MVI)-based facilitation programme on AM and EFT functioning in the context of a randomised-controlled trial study in RR-MS patients. METHODS: Using the Autobiographical Interview (AI), 40 patients presenting with an AM/EFT impairment were randomly assigned in three groups: (i) the experimental (n = 17), who followed the MVI programme, (ii) the verbal control (n = 10), who followed a sham verbal programme, and (iii) the stability groups (n = 13), who underwent the AM/EFT test twice, with no intervention in between. RESULTS: AI's second assessment scores showed a significant improvement of AM and EFT performance only for the experimental group, with a long-term robustness of treatment benefits. CONCLUSIONS: The control and stability groups' results ruled out nursing and test learning effects as explanations of AM/EFT improvement. These benefits were corroborated by the patients' comments, which indicated an effective MVI strategy transfer to daily life. Our results suggest that the MVI programme tackles a common cognitive process of scene construction present in AM and EFT.journal articlerandomized controlled trialresearch support, non-u.s. gov't2015importe

St. Augustine’s Reflections on Memory and Time and the Current Concept of Subjective Time in Mental Time Travel

behavioral science

Neural correlates of episodic future thinking impairment in multiple sclerosis patients

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.journal articleresearch support, non-u.s. gov't2015importe