Liliann Manning

Induced Brain Plasticity after a Facilitation Programme for Autobiographical Memory in Multiple Sclerosis: A Preliminary Study

This preliminary study tackles the assessment and treatment of autobiographical memory (AbM) in relapsing-remitting multiple sclerosis (RR-MS) patients. Our aim was to investigate cerebral activation changes, following clinical improvement of AbM due to a cognitive training based on mental visual imagery (MVI). We assessed AbM using the Autobiographical Interview (AI) in eight patients and 15 controls. The latter subjects established normative data. The eight patients showed selective defective performance on the AI. Four patients were trained cognitively and underwent pre- and post-AI and fMRI. The remaining four patients took a second AI, at the same interval, but with no intervention in between. Results showed a significant improvement of AbM performance after the facilitation programme that could not be explained by learning effects since the AI scores remained stable between the two assessments in the second group of patients. As expected, AbM improvement was accompanied by an increased cerebral activity in posterior cerebral regions in post-facilitation fMRI examination. We interpret this activation changes in terms of reflecting the emphasis made on the role of MVI in memory retrieval through the facilitation programme. These preliminary significant clinical and neuroimaging changes suggest the beneficial effects of this technique to alleviate AbM retrieval deficit in MS patients.

The influence of seizure frequency on anterograde and remote memory in mesial temporal lobe epilepsy

PURPOSE Seizure frequency, although considered as an important factor in memory impairment in mesial temporal epilepsy (mTLE), is mostly confounded with other clinical variables, making it unclear to what extent recurrent seizures actually interfere with memory. The present study focuses on the influence of seizure frequency, studied as a main variable, on anterograde and remote memory. METHODS Seventy-one patients with unilateral mTLE were divided into two subgroups, as a function of their seizure frequency (monthly versus weekly seizures). Other seizure-related variables were controlled, namely, lateralisation and type of lesion, age at onset, years of ongoing seizures, etiologic factors, and number of AED. A comprehensive neuropsychological examination, including anterograde memory (verbal and non verbal recognition memory and free recall) tasks together with a large range of tests exploring different domains of remote memory, was carried out. RESULTS Despite similar results on IQ, executive functions and attention, the low seizure-frequency group performed significantly better than the high seizure-frequency group on anterograde memory tests. Loss of autobiographical episodes and public-events memory, concomitant with spared personal semantic knowledge, was observed in both patient groups compared with healthy subjects. A worsening effect of high seizure frequency was recorded for autobiographical incidents and news-events memory, but unexpectedly, not for memory for famous people. CONCLUSION The study of seizure frequency as the main variable leads us to suggest that high seizure frequency, itself, potentiates the effects of mesial temporal lobe damage on episodic memory deficits.

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.

Wearable Cameras Are Useful Tools to Investigate and Remediate Autobiographical Memory Impairment: A Systematic PRISMA Review

Autobiographical memory, central in human cognition and every day functioning, enables past experienced events to be remembered. A variety of disorders affecting autobiographical memory are characterized by the difficulty of retrieving specific detailed memories of past personal events. Owing to the impact of autobiographical memory impairment on patients’ daily life, it is necessary to better understand these deficits and develop relevant methods to improve autobiographical memory. The primary objective of the present systematic PRISMA review was to give an overview of the first empirical evidence of the potential of wearable cameras in autobiographical memory investigation in remediating autobiographical memory impairments. The peer-reviewed literature published since 2004 on the usefulness of wearable cameras in research protocols was explored in 3 databases (PUBMED, PsycINFO, and Google Scholar). Twenty-eight published studies that used a protocol involving wearable camera, either to explore wearable camera functioning and impact on daily life, or to investigate autobiographical memory processing or remediate autobiographical memory impairment, were included. This review analyzed the potential of wearable cameras for 1) investigating autobiographical memory processes in healthy volunteers without memory impairment and in clinical populations, and 2) remediating autobiographical memory in patients with various kinds of memory disorder. Mechanisms to account for the efficacy of wearable cameras are also discussed. The review concludes by discussing certain limitations inherent to using cameras, and new research perspectives. Finally, ethical issues raised by this new technology are considered.

Different Temporal Patterns of Specific and General Autobiographical Memories across the Lifespan in Alzheimer’s Disease

We compared specific (i.e., associated with a unique time and space) and general (i.e., extended or repeated events) autobiographical memories (AbM) in Alzheimers disease (AD). The comparison aims at investigating the relationship between these two components of AbM across the lifespan and the volume of cerebral regions of interest within the temporal lobe. We hypothesized that the ability to elicit specific memories would correlate with hippocampal volume, whereas evoking general memories would be related to lateral temporal lobe. AbM was assessed using the modified Crovitz test in 18 patients with early AD and 18 matched controls. The proportions of total memories—supposed to reflect the ability to produce general memories—and specific memories retrieved were compared between AD patients and controls. Correlations to MRI volumes of temporal cortex were tested. We found different temporal patterns for specific and general memories in AD patients, with (i) relatively spared general memories, according to a temporal gradient that preserved remote memories, predominantly associated with right lateral temporal cortex volume. (ii) Conversely, the retrieval of specific AbMs was impaired for all life periods and correlated with bilateral hippocampal volumes. Our results highlight a shift from an initially episodic to a semantic nature of AbMs during AD, where the abstracted form of memories remains.

Benefits from an autobiographical memory facilitation programme in relapsing- remitting multiple sclerosis patients: a clinical and neuroimaging study

ABSTRACT While the efficacy of mental visual imagery (MVI) to alleviate autobiographical memory (AM) impairment in multiple sclerosis (MS) patients has been documented, nothing is known about the brain changes sustaining that improvement. To explore this issue, 20 relapsing-remitting MS patients showing AM impairment were randomly assigned to two groups, experimental (n = 10), who underwent the MVI programme, and control (n = 10), who followed a sham verbal programme. Besides the stringent AM assessment, the patients underwent structural and functional MRI sessions, consisting in retrieving personal memories, within a pre-/post-facilitation study design. Only the experimental group showed a significant AM improvement in post-facilitation, accompanied by changes in brain activation (medial and lateral frontal regions), functional connectivity (posterior brain regions), and grey matter volume (parahippocampal gyrus). Minor activations and functional connectivity changes were observed in the control group. The MVI programme improved AM in MS patients leading to functional and structural changes reflecting (1) an increase reliance on brain regions sustaining a self-referential process; (2) a decrease of those reflecting an effortful research process; and (3) better use of neural resources in brain regions sustaining MVI. Functional changes reported in the control group likely reflected ineffective attempts to use the sham strategy in AM.

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 ones own past as well as being able to project into ones 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.

THE MEDIAL PREFRONTAL CORTEX SUPPORTS OF THE SENSE OF SELF IN ALZHEIMER’S DISEASE

differences in ultrastructure of capillary basal lamina (CBL) in humans (normal and diseased, <50 years) compared with mouse (young to middle age). Methods: Human autopsy brains without or with neurodegeneration, including Parkinson’s disease, frontotemporal degeneration and amyotrophic lateral sclerosis, and mouse models of tauopathy were evaluated. Brain tissues were fixed in formaldehyde and/or glutaraldehyde and processed for electron microscopy (EM) or post-embedding immunogold EM. Antibodies to types I, III and IV collagen and to fibronectin were used. Results: Mouse CBL is a thin and uniformly amorphous structure that is labeled with anti-type IV collagen in both normal mice and models of neurodegenerative disease at all ages. In contrast, the CBL in normal and diseased human brains has the amorphous BL, but also banded collagens. In addition, the BL frequently shows segmental splitting between endothelial and astrocytic sides of the BL. The split creates an expanded space that contains banded fibrils of type I and III collagen, but not type IV collagen. The expansion and splitting of BL increase with age and in diseased brains. The CBL in diseased human brains often extends into the pericapillary space. Anti-fibronectin co-localizes with collagens. These ultrastructural features are rarely observed in mice, but are detected in the youngest human brains studied. Conclusions: Human CBL has ageand disease-related alternations including split BL and accumulation of banded type I and III collagen fibrils associated with fibronectin. This BL “fibrosis” is rarely observed in mice brains. If these structural BL alterations are associated with capillary dysfunction, the lack of these changes inmicewarrants caution about use of mouse models for neurovascular studies.