scholarly journals Comparison of fMRI correlates of successful episodic memory encoding in temporal lobe epilepsy patients and healthy controls

NeuroImage ◽  
2020 ◽  
Vol 207 ◽  
pp. 116397 ◽  
Author(s):  
Paul F. Hill ◽  
Danielle R. King ◽  
Bradley C. Lega ◽  
Michael D. Rugg
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Healthy Controls ◽  
Memory Encoding

Atypical neural topographies underpin dysfunctional pattern separation in temporal lobe epilepsy

Brain ◽  
2021 ◽  
Author(s):  
Qiongling Li ◽  
Shahin Tavakol ◽  
Jessica Royer ◽  
Sara Larivière ◽  
Reinder Vos De Wael ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Neural Activity ◽  
Pattern Separation ◽  
Healthy Controls ◽  
Intrinsic Connectivity ◽  
Measures Of Concordance ◽  
Anterior Segments ◽  
Topographic Gradients

Abstract Episodic memory is the ability to accurately remember events from our past. The process of pattern separation is hypothesized to underpin this ability and is defined as the ability to orthogonalize memory traces, to maximize the features that make them unique. Contemporary cognitive neuroscience suggests that pattern separation entails complex interactions between the hippocampus and the neocortex, where specific hippocampal subregions shape neural reinstatement in the neocortex. To test this hypothesis, the current work studied both healthy controls and patients with temporal lobe epilepsy (TLE) who present with hippocampal structural anomalies. In all participants, we measured neural activity using functional magnetic resonance imaging (fMRI) while they retrieved memorized items compared to lure items which share features with the target. Behaviorally, TLE patients were less able to exclude lures than controls, and showed a reduction in pattern separation. To assess the hypothesized relationship between neural patterns in the hippocampus and the neocortex, we identified topographic gradients of intrinsic connectivity along neocortical and hippocampal subfield surfaces and identified the topographic profile of the neural activity accompanying pattern separation. In healthy controls, pattern separation followed a graded pattern of neural activity, both along the hippocampal long axis (and peaked in anterior segments that are more heavily engaged in transmodal processing) and along the neocortical hierarchy running from unimodal to transmodal regions (peaking in transmodal default mode regions). In TLE patients, however, this concordance between task-based functional activations and topographic gradients was markedly reduced. Furthermore, person specific measures of concordance between task-related activity and connectivity gradients in patients and controls related to inter-individual differences in behavioral measures of pattern separation and episodic memory, highlighting the functional relevance of the observed topographic motifs. Our work is consistent with an emerging understanding that successful discrimination between memories with similar features entails a shift in the locus of neural activity away from sensory systems, a pattern that is mirrored along the hippocampal long axis and with respect to neocortical hierarchies. More broadly, our study establishes topographic profiling using intrinsic connectivity gradients captures the functional underpinnings of episodic memory processes in manner that is sensitive to their reorganization in pathology.

Autobiographical Memory in Children with Temporal Lobe Epilepsy

2013 ◽  
Vol 19 (10) ◽  
pp. 1076-1086 ◽  
Author(s):  
Michael B. Gascoigne ◽  
Mary Lou Smith ◽  
Richard Webster ◽  
Belinda Barton ◽  
Deepak Gill ◽  
...  
Keyword(s):  
Socioeconomic Status ◽  
Episodic Memory ◽  
Temporal Lobe Epilepsy ◽  
Autobiographical Memory ◽  
Semantic Memory ◽  
Temporal Lobe ◽  
Memory Deficits ◽  
Healthy Controls ◽  
Healthy Control

AbstractAutobiographical memory involves the recall of personal facts (semantic memory) and re-experiencing of specific personal events (episodic memory). Although impairments in autobiographical memory have been found in adults with unilateral temporal lobe epilepsy (TLE) and attributed to compromised hippocampal integrity, it is not yet known whether this occurs in children with TLE. In the current study, 21 children with TLE and 24 healthy controls of comparable age, sex, and socioeconomic status were administered the Children's Autobiographical Interview. Compared to controls, children with TLE recalled fewer episodic details, but only when no retrieval prompts were provided. There was no difference between the groups for semantic autobiographic details. Interestingly, the number of episodic details recalled increased significantly from 6 to 16 years of age in healthy control children, but not in children with TLE. Exploratory analyses revealed that, within the group of children with TLE, epilepsy factors, including presence or absence of structural hippocampal abnormalities, did not relate to the richness of episodic recall. Our results provide first evidence of autobiographical episodic memory deficits in children with TLE. (JINS, 2013, 19, 1–12)

scholarly journals Semantic Processing Impairment in Patients with Temporal Lobe Epilepsy

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Amanda G. Jaimes-Bautista ◽  
Mario Rodríguez-Camacho ◽  
Iris E. Martínez-Juárez ◽  
Yaneth Rodríguez-Agudelo
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Semantic Processing ◽  
Functional Neuroimaging ◽  
Declarative Memory ◽  
Semantic Networks ◽  
N400 Effect ◽  
Functional Reorganization ◽  
Electrophysiological Studies

The impairment in episodic memory system is the best-known cognitive deficit in patients with temporal lobe epilepsy (TLE). Recent studies have shown evidence of semantic disorders, but they have been less studied than episodic memory. The semantic dysfunction in TLE has various cognitive manifestations, such as the presence of language disorders characterized by defects in naming, verbal fluency, or remote semantic information retrieval, which affects the ability of patients to interact with their surroundings. This paper is a review of recent research about the consequences of TLE on semantic processing, considering neuropsychological, electrophysiological, and neuroimaging findings, as well as the functional role of the hippocampus in semantic processing. The evidence from these studies shows disturbance of semantic memory in patients with TLE and supports the theory of declarative memory of the hippocampus. Functional neuroimaging studies show an inefficient compensatory functional reorganization of semantic networks and electrophysiological studies show a lack of N400 effect that could indicate that the deficit in semantic processing in patients with TLE could be due to a failure in the mechanisms of automatic access to lexicon.

scholarly journals Elevated IL-6 and IL-1β are associated with temporal lobe epilepsy: A study in Chinese patients

2018 ◽  
Vol 16 ◽  
pp. 205873921877893 ◽  
Author(s):  
Li Xia ◽  
Song-Qing Pan ◽  
Qiu-Min Zhang ◽  
Qin Zhou ◽  
Lu Xia ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Chinese Patients ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Controls ◽  
Temporal Epilepsy ◽  
Tnf Α ◽  
Plasma Cytokines ◽  
Proinflammatory Molecules ◽  
Positive Correlations

Activation of proinflammatory cytokines in seizures has been well characterized. However, role of cytokines in epilepsy and association with different clinical phenotype has not been well investigated. Reports on possible link between proinflammatory molecules and epilepsy are very limited. In this study, we performed a hospital-based case control study to investigate the association of plasma cytokines and their expression with different clinical categories of epilepsy. Patients admitted to Neurology Department of Renmin Hospital were enrolled in this study after clinical investigations. In all, 92 patients with temporal lobe epilepsy (TLE) and 45 with extra-temporal lobe epilepsy (XTLE) were included in this study. Furthermore, we included 86 healthy controls from the similar geographical population. Plasma levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β were quantified by enzyme-linked immunosorbent assay (ELISA). All plasma cytokines were elevated in TLE and XTLE compared to healthy controls ( P < 0.0001). Furthermore, IL-6 and IL-1β were significantly higher in TLE when compared to extra-temporal epilepsy. Incidentally, no difference in mean plasma TNF-α levels was noticed among TLE and XTLE. Positive correlations were observed between all plasma proinflammatory molecules (TNF-α, IL-6, and IL-1β) investigated in this study. Epilepsy patients displayed higher proinflammatory molecules, namely, IL-6, IL-1β, and TNF-α. Plasma IL-6 and IL-1β can be use as biomarkers for differentiation of TLE from XTLE.

scholarly journals Remote Episodic Memory Deficits in Patients with Unilateral Temporal Lobe Epilepsy and Excisions

2000 ◽  
Vol 20 (15) ◽  
pp. 5853-5857 ◽  
Author(s):  
Indre V. Viskontas ◽  
Mary Pat McAndrews ◽  
Morris Moscovitch
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Memory Deficits

Default mode network connectivity indicates episodic memory capacity in mesial temporal lobe epilepsy

Epilepsia ◽  
2013 ◽  
Vol 54 (5) ◽  
pp. 809-818 ◽  
Author(s):  
Cornelia McCormick ◽  
Maher Quraan ◽  
Melanie Cohn ◽  
Taufik A. Valiante ◽  
Mary Pat McAndrews
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Default Mode Network ◽  
Network Connectivity ◽  
Memory Capacity ◽  
Mesial Temporal Lobe Epilepsy ◽  
Default Mode ◽  
Mesial Temporal Lobe

scholarly journals Transcriptionally Less Active Prodynorphin Promoter Alleles are Associated with Temporal Lobe Epilepsy: A Case-Control Study and Meta-Analysis

2008 ◽  
Vol 24 (3) ◽  
pp. 135-140 ◽  
Author(s):  
Marcelo A. Kauffman ◽  
Damián Consalvo ◽  
Moron Dolores Gonzalez ◽  
Silvia Kochen
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Fixed Effects ◽  
Association Studies ◽  
Hippocampal Sclerosis ◽  
Meta Analysis ◽  
Case Control ◽  
Healthy Controls ◽  
Fixed Effects Model ◽  
Familial Predisposition

We performed an association study in a population of patients with Mesial Temporal Lobe Epilepsy (TLE) with Hippocampal Sclerosis (MTEHS) together with a systematic revision of the literature to investigate the role of transcriptionally less active polymorphic alleles of Prodynorphin (PDYN) gene in this pathology. We included 102 patients with a diagnosis of MTEHS and 86 healthy controls. The positive antecedent of family history for epileptic events defined a TLE subgroup with familial predisposition for epileptic disorders. The PDYN promoter polymorphism was genotyped by means of a PCR assay. For meta-analysis, we identified case-control association studies between TLE and PDYN by searching PUBMED. The pooled OR was estimated using a fixed effects model under dominant and co-dominant heredity models. No differences in genotypic and allelic frequencies were found between cases and controls (p= 0.61) in our population, neither in the whole cohort nor in the analysis limited to TLE with familial predisposition (p= 0.71). The Meta-Analysis included 591 TLE patients and 1117 healthy controls. We found an association between L allele (p= 0.003; OR = 1.40; IC 95 = 1.12–1.74) and a modestly higher risk to develop TLE in the group of patients with familial predisposition. Therefore, functional allelic variants in the PDYN promoter might modify the risk to develop TLE in subjects with familial predisposition.

Functional imaging of semantic memory predicts postoperative episodic memory functions in chronic temporal lobe epilepsy

2008 ◽  
Vol 1223 ◽  
pp. 73-81 ◽  
Author(s):  
Bülent Köylü ◽  
Gerald Walser ◽  
Anja Ischebeck ◽  
Martin Ortler ◽  
Thomas Benke
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe Epilepsy ◽  
Semantic Memory ◽  
Temporal Lobe ◽  
Functional Imaging ◽  
Memory Functions

scholarly journals Aberrant prefrontal beta oscillations predict episodic memory encoding deficits in schizophrenia

2016 ◽  
Author(s):  
Federica Meconi ◽  
Sarah Anderl-Straub ◽  
Heidelore Raum ◽  
Michael Landgrebe ◽  
Berthold Langguth ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Verbal Memory ◽  
Semantic Processing ◽  
Memory Performance ◽  
Oscillatory Activity ◽  
Healthy Controls ◽  
Memory Encoding ◽  
Brain Oscillations ◽  
Beta Power ◽  
Pattern Similarity

AbstractVerbal episodic memory is one of the core cognitive functions affected in patients suffering from schizophrenia (SZ). Although this verbal memory impairment in SZ is a well-known finding, our understanding about its underlying neurophysiological mechanisms is rather scarce. Here we address this issue by recording brain oscillations during a memory task in a sample of healthy controls and patients suffering from SZ. Brain oscillations represent spectral fingerprints of specific neurocognitive operations and are therefore a promising tool to identify neurocognitive mechanisms that are affected by SZ. Healthy controls showed a prominent suppression of left prefrontal beta oscillatory activity during successful memory formation, which replicates several previous oscillatory memory studies. In contrast, patients failed to exhibit such left prefrontal beta power suppression. Utilizing a new topographical pattern similarity approach, we further demonstrate that the degree of similarity between a patient's beta power decrease to that of the controls reliably predicted memory performance. This relationship between beta power decreases and memory was such that the patients' memory performance improved as they showed a more similar topographical beta desynchronization pattern compared to that of healthy controls. These findings suggest that left prefrontal beta power suppression (or lack thereof) during memory encoding is a possible biomarker for the observed encoding impairments in SZ in verbal memory. This lack of left prefrontal beta power decreases might indicate a specific semantic processing deficit of verbal material in patients with schizophrenia.

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