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.

scholarly journals Investigating the Effects of Seizures on Procedural Memory Performance in Patients with Epilepsy

2021 ◽  
Vol 11 (2) ◽  
pp. 261
Author(s):  
Frank J. van Schalkwijk ◽  
Walter R. Gruber ◽  
Laurie A. Miller ◽  
Eugen Trinka ◽  
Yvonne Höller
Keyword(s):  
Temporal Lobe ◽  
Declarative Memory ◽  
Memory Performance ◽  
Total Sample ◽  
Learning Task ◽  
Procedural Memory ◽  
Memory Retention ◽  
Motor Sequence ◽  
Performance Improvements ◽  
Patients With Epilepsy

Memory complaints are frequently reported by patients with epilepsy and are associated with seizure occurrence. Yet, the direct effects of seizures on memory retention are difficult to assess given their unpredictability. Furthermore, previous investigations have predominantly assessed declarative memory. This study evaluated within-subject effects of seizure occurrence on retention and consolidation of a procedural motor sequence learning task in patients with epilepsy undergoing continuous monitoring for five consecutive days. Of the total sample of patients considered for analyses (N = 53, Mage = 32.92 ± 13.80 y, range = 18–66 y; 43% male), 15 patients experienced seizures and were used for within-patient analyses. Within-patient contrasts showed general improvements over seizure-free (day + night) and seizure-affected retention periods. Yet, exploratory within-subject contrasts for patients diagnosed with temporal lobe epilepsy (n = 10) showed that only seizure-free retention periods resulted in significant improvements, as no performance changes were observed following seizure-affected retention. These results indicate general performance improvements and offline consolidation of procedural memory during the day and night. Furthermore, these results suggest the relevance of healthy temporal lobe functioning for successful consolidation of procedural information, as well as the importance of seizure control for effective retention and consolidation of procedural memory.

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 High feature overlap reveals the importance of anterior and medial temporal lobe structures for learning by means of fast mapping

2020 ◽  
Author(s):  
Ann-Kathrin Zaiser ◽  
Regine Bader ◽  
Patric Meyer
Keyword(s):  
Medial Temporal Lobe ◽  
Declarative Memory ◽  
Perirhinal Cortex ◽  
Semantic Integration ◽  
The Novel ◽  
Fast Mapping ◽  
Learning Procedure ◽  
Feature Overlap ◽  
High Degree ◽  
Novel Associations

AbstractContrary to traditional theories of declarative memory, it has recently been shown that novel, arbitrary associations can be rapidly and directly integrated into cortical memory networks by means of a learning procedure called fast mapping (FM), possibly bypassing time-consuming hippocampal-neocortical consolidation processes. In the typical FM paradigm, a picture of a previously unknown item is presented next to a picture of a previously known item and participants answer a question referring to an unfamiliar label. It is assumed that they thereby incidentally create associations between the unknown item and the label. However, contradictory findings have been reported and factors moderating rapid cortical integration through FM yet need to be identified. In the context of previous behavioral results showing rapid semantic integration through FM especially if the unknown and the known item shared many features, we propose that due to its computational mechanisms during the processing of complex and particularly highly similar objects, the perirhinal cortex might be especially qualified to support the rapid incorporation of these associations into cortical memory networks within the FM paradigm. We therefore expected that a high degree of feature overlap between the unknown and the known item would trigger strong engagement of the perirhinal cortex at encoding, which in turn might enhance rapid cortical integration of the novel picture-label associations. Within an fMRI experiment, we observed stronger activation for subsequent hits than misses during encoding in the perirhinal cortex and an associated anterior temporal network if the items shared many features than if they shared few features, indicating that the perirhinal cortex indeed contributes to the acquisition of novel associations by means of FM if feature overlap is high.

scholarly journals Timecourse and convergence of abstract and concrete knowledge in the anterior temporal lobe

2020 ◽  
Author(s):  
L. Vignali ◽  
Y. Xu ◽  
J. Turini ◽  
O. Collignon ◽  
D. Crepaldi ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Conceptual Knowledge ◽  
Word Processing ◽  
Semantic Information ◽  
Anterior Temporal Lobe ◽  
Conceptual Processing ◽  
Feature Spaces ◽  
Semantic Hub ◽  
Late Stages ◽  
The Brain

AbstractHow is conceptual knowledge organized and retrieved by the brain? Recent evidence points to the anterior temporal lobe (ATL) as a crucial semantic hub integrating both abstract and concrete conceptual features according to a dorsal-to-medial gradient. It is however unclear when this conceptual gradient emerges and how semantic information reaches the ATL during conceptual retrieval. Here we used a multiple regression approach to magnetoencephalography signals of spoken words, combined with dimensionality reduction in concrete and abstract semantic feature spaces. Results showed that the dorsal-to-medial abstract-to-concrete ATL gradient emerges only in late stages of word processing: Abstract and concrete semantic information are initially encoded in posterior temporal regions and travel along separate cortical pathways eventually converging in the ATL. The present finding sheds light on the neural dynamics of conceptual processing that shape the organization of knowledge in the anterior temporal lobe.

scholarly journals A nonverbal route to conceptual knowledge involving the right anterior temporal lobe

2018 ◽  
Vol 117 ◽  
pp. 92-101 ◽  
Author(s):  
Robert S. Hurley ◽  
M.-Marsel Mesulam ◽  
Jaiashre Sridhar ◽  
Emily J. Rogalski ◽  
Cynthia K. Thompson
Keyword(s):  
Temporal Lobe ◽  
Conceptual Knowledge ◽  
Anterior Temporal Lobe ◽  
The Right

scholarly journals The Ventrolateral Anterior Temporal Lobe is Commonly Engaged by Both Mental State Inference and Semantic Association Tasks

2021 ◽  
Author(s):  
Eva Balgova ◽  
Veronica Diveica ◽  
Jon Walbrin ◽  
Richard J. Binney
Keyword(s):  
Social Cognition ◽  
Temporal Lobe ◽  
Conceptual Knowledge ◽  
Semantic Representation ◽  
Brain Regions ◽  
Anterior Temporal Lobe ◽  
General Role ◽  
Social Ability ◽  
Domain Specific ◽  
State Inference

AbstractA key challenge for neurobiological models of social cognition is to elucidate whether brain regions are specialised for that domain. In recent years, discussion surrounding the role of the anterior temporal lobe (ATL) epitomises such debates; some argue it is part of a domain-specific network for social processing, while others claim it is a domain-general hub for semantic representation. In the present study, we used ATL-optimised fMRI to map the contribution of different ATL structures to a variety of paradigms frequently used to probe a crucial social ability, namely ‘theory of mind’ (ToM). Using multiple tasks enables a clearer attribution of activation to ToM as opposed to idiosyncratic features of stimuli. Further, we directly explored whether these same structures are also activated by a non-social task probing semantic representations. We revealed that common to all of the tasks was activation of a key ventrolateral ATL region that is typically invisible to standard fMRI. This constitutes novel evidence in support of the view that the ventrolateral ATL contributes to social cognition via a domain-general role in the retrieval of conceptual knowledge, and against claims of a specialised social function.

Learning and Consolidation of Verbal Declarative Memory in Patients with Posttraumatic Stress Disorder

2010 ◽  
Vol 218 (2) ◽  
pp. 135-140 ◽  
Author(s):  
Slawomira J. Diener ◽  
Herta Flor ◽  
Michèle Wessa
Keyword(s):  
Posttraumatic Stress Disorder ◽  
Posttraumatic Stress ◽  
Verbal Memory ◽  
Stress Disorder ◽  
Declarative Memory ◽  
Memory Performance ◽  
Verbal Learning ◽  
Depression Scale ◽  
Learning Performance ◽  
Ptsd Symptoms

Impairments in declarative memory have been reported in posttraumatic stress disorder (PTSD). Fragmentation of explicit trauma-related memory has been assumed to impede the formation of a coherent memorization of the traumatic event and the integration into autobiographic memory. Together with a strong non-declarative memory that connects trauma reminders with a fear response the impairment in declarative memory is thought to be involved in the maintenance of PTSD symptoms. Fourteen PTSD patients, 14 traumatized subjects without PTSD, and 13 non-traumatized healthy controls (HC) were tested with the California Verbal Learning Test (CVLT) to assess verbal declarative memory. PTSD symptoms were assessed with the Clinician Administered PTSD Scale and depression with the Center of Epidemiological Studies Depression Scale. Several indices of the CVLT pointed to an impairment in declarative memory performance in PTSD, but not in traumatized persons without PTSD or HC. No group differences were observed if recall of memory after a time delay was set in relation to initial learning performance. In the PTSD group verbal memory performance correlated significantly with hyperarousal symptoms, after concentration difficulties were accounted for. The present study confirmed previous reports of declarative verbal memory deficits in PTSD. Extending previous results, we propose that learning rather than memory consolidation is impaired in PTSD patients. Furthermore, arousal symptoms may interfere with successful memory formation in PTSD.

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