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 Decoding the Formation of New Semantics: MVPA Investigation of Rapid Neocortical Plasticity during Associative Encoding through Fast Mapping

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Tali Atir-Sharon ◽  
Asaf Gilboa ◽  
Hananel Hazan ◽  
Ester Koilis ◽  
Larry M. Manevitz
Keyword(s):  
Temporal Lobe ◽  
Conceptual Knowledge ◽  
Cortical Plasticity ◽  
Declarative Memory ◽  
Memory Performance ◽  
Activity Patterns ◽  
Semantic Networks ◽  
Fast Mapping ◽  
Anterior Temporal Lobe ◽  
Novel Associations

Neocortical structures typically only support slow acquisition of declarative memory; however, learning through fast mapping may facilitate rapid learning-induced cortical plasticity and hippocampal-independent integration of novel associations into existing semantic networks. During fast mapping the meaning of new words and concepts is inferred, and durable novel associations are incidentally formed, a process thought to support early childhood’s exuberant learning. The anterior temporal lobe, a cortical semantic memory hub, may critically support such learning. We investigated encoding of semantic associations through fast mapping using fMRI and multivoxel pattern analysis. Subsequent memory performance following fast mapping was more efficiently predicted using anterior temporal lobe than hippocampal voxels, while standard explicit encoding was best predicted by hippocampal activity. Searchlight algorithms revealed additional activity patterns that predicted successful fast mapping semantic learning located in lateral occipitotemporal and parietotemporal neocortex and ventrolateral prefrontal cortex. By contrast, successful explicit encoding could be classified by activity in medial and dorsolateral prefrontal and parahippocampal cortices. We propose that fast mapping promotes incidental rapid integration of new associations into existing neocortical semantic networks by activating related, nonoverlapping conceptual knowledge. In healthy adults, this is better captured by unique anterior and lateral temporal lobe activity patterns, while hippocampal involvement is less predictive of this kind of learning.

Modulation of medial temporal lobe activity in epilepsy patients with hippocampal sclerosis during verbal working memory

2009 ◽  
Vol 15 (4) ◽  
pp. 536-546 ◽  
Author(s):  
PABLO CAMPO ◽  
FERNANDO MAESTÚ ◽  
IRENE GARCÍA-MORALES ◽  
ANTONIO GIL-NAGEL ◽  
BRYAN STRANGE ◽  
...  
Keyword(s):  
Working Memory ◽  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Time Course ◽  
Hippocampal Sclerosis ◽  
Stimulus Presentation ◽  
Verbal Working Memory ◽  
Compelling Evidence ◽  
Electrophysiological Studies

AbstractIt has been traditionally assumed that medial temporal lobe (MTL) is not required for working memory (WM). However, animal lesion and electrophysiological studies and human neuropsychological and neuroimaging studies have provided increasing evidences of a critical involvement of MTL in WM. Based on previous findings, the central aim of this study was to investigate the contribution of the MTL to verbal WM encoding. Here, we used magnetoencephalography (MEG) to compare the patterns of MTL activation of 9 epilepsy patients suffering from left hippocampal sclerosis with those of 10 healthy matched controls while they performed a verbal WM task. MEG recordings allow detailed tracking of the time course of MTL activation. We observed impaired WM performance associated with changes in the dynamics of MTL activity in epilepsy patients. Specifically, whereas patients showed decreased activity in damaged MTL, activity in the contralateral MTL was enhanced, an effect that became significant in the 600- to 700-ms interval after stimulus presentation. These findings strongly support the crucial contribution of MTL to verbal WM encoding and provide compelling evidence for the proposal that MTL contributes to both episodic memory and WM. Whether this pattern is signaling reorganization or a normal use of a damaged structure is discussed. (JINS, 2009, 15, 536–546.)

scholarly journals Neuropsychology in Temporal Lobe Epilepsy: Influences from Cognitive Neuroscience and Functional Neuroimaging

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Mary Pat McAndrews ◽  
Melanie Cohn
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Functional Imaging ◽  
Cognitive Neuroscience ◽  
Surgical Planning ◽  
Current Practice ◽  
Functional Neuroimaging ◽  
Mapping Function ◽  
Current Assessment ◽  
Assessment Strategies

Neuropsychologists assist in diagnosis (i.e., localization of dysfunction) and in prediction (i.e., how cognition may change following surgery) in individuals being considered for temporal lobe surgery. The current practice includes behavioural testing as well as mapping function via stimulation, inactivation, and (more recently) functional imaging. These methods have been providing valuable information in surgical planning for 60 years. Here, we discuss current assessment strategies and highlight how they are evolving, particularly with respect to integrating recent advances in cognitive neuroscience.

scholarly journals Syntactic and Semantic Modulation of Neural Activity during Auditory Sentence Comprehension

2006 ◽  
Vol 18 (4) ◽  
pp. 665-679 ◽  
Author(s):  
Colin Humphries ◽  
Jeffrey R. Binder ◽  
David A. Medler ◽  
Einat Liebenthal
Keyword(s):  
Temporal Lobe ◽  
Word Order ◽  
Semantic Processing ◽  
Sentence Comprehension ◽  
Functional Neuroimaging ◽  
Syntactic Structure ◽  
Imaging Study ◽  
Angular Gyrus ◽  
Semantic Structure ◽  
Word Lists

In previous functional neuroimaging studies, left anterior temporal and temporal-parietal areas responded more strongly to sentences than to randomly ordered lists of words. The smaller response for word lists could be explained by either (1) less activation of syntactic processes due to the absence of syntactic structure in the random word lists or (2) less activation of semantic processes resulting from failure to combine the content words into a global meaning. To test these two explanations, we conducted a functional magnetic resonance imaging study in which word order and combinatorial word meaning were independently manipulated during auditory comprehension. Subjects heard six different stimuli: normal sentences, semantically incongruent sentences in which content words were randomly replaced with other content words, pseudoword sentences, and versions of these three sentence types in which word order was randomized to remove syntactic structure. Effects of syntactic structure (greater activation to sentences than to word lists) were observed in the left anterior superior temporal sulcus and left angular gyrus. Semantic effects (greater activation to semantically congruent stimuli than either incongruent or pseudoword stimuli) were seen in widespread, bilateral temporal lobe areas and the angular gyrus. Of the two regions that responded to syntactic structure, the angular gyrus showed a greater response to semantic structure, suggesting that reduced activation for word lists in this area is related to a disruption in semantic processing. The anterior temporal lobe, on the other hand, was relatively insensitive to manipulations of semantic structure, suggesting that syntactic information plays a greater role in driving activation in this area.

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 Disturbance of semantic processing in temporal lobe epilepsy demonstrated with scalp ERPs

Seizure ◽  
2000 ◽  
Vol 9 (8) ◽  
pp. 572-579 ◽  
Author(s):  
Tamaki Miyamoto ◽  
Jun’ ichi Katayama ◽  
Masako Kohsaka ◽  
Tsukasa Koyama
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Semantic Processing

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 Mapping of Language-and-Memory Networks in Patients With Temporal Lobe Epilepsy by Using the GE2REC Protocol

2022 ◽  
Vol 15 ◽  
Author(s):  
Sonja Banjac ◽  
Elise Roger ◽  
Emilie Cousin ◽  
Chrystèle Mosca ◽  
Lorella Minotti ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Declarative Memory ◽  
Cognitive Outcomes ◽  
Individual Level ◽  
Preoperative Mapping ◽  
Neurosurgical Planning ◽  
Cerebral Reorganization ◽  
Memory Network

Preoperative mapping of language and declarative memory functions in temporal lobe epilepsy (TLE) patients is essential since they frequently encounter deterioration of these functions and show variable degrees of cerebral reorganization. Due to growing evidence on language and declarative memory interdependence at a neural and neuropsychological level, we propose the GE2REC protocol for interactive language-and-memory network (LMN) mapping. GE2REC consists of three inter-related tasks, sentence generation with implicit encoding (GE) and two recollection (2REC) memory tasks: recognition and recall. This protocol has previously been validated in healthy participants, and in this study, we showed that it also maps the LMN in the left TLE (N = 18). Compared to healthy controls (N = 19), left TLE (LTLE) showed widespread inter- and intra-hemispheric reorganization of the LMN through reduced activity of regions engaged in the integration and the coordination of this meta-network. We also illustrated how this protocol could be implemented in clinical practice individually by presenting two case studies of LTLE patients who underwent efficient surgery and became seizure-free but showed different cognitive outcomes. This protocol can be advantageous for clinical practice because it (a) is short and easy to perform; (b) allows brain mapping of essential cognitive functions, even at an individual level; (c) engages language-and-memory interaction allowing to evaluate the integrative processes within the LMN; (d) provides a more comprehensive assessment by including both verbal and visual modalities, as well as various language and memory processes. Based on the available postsurgical data, we presented preliminary results obtained with this protocol in LTLE patients that could potentially inform the clinical practice. This implies the necessity to further validate the potential of GE2REC for neurosurgical planning, along with two directions, guiding resection and describing LMN neuroplasticity at an individual level.

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