The reliability of fMRI activations in the medial temporal lobes in a verbal episodic memory task

NeuroImage ◽  
2005 ◽  
Vol 28 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Kathrin Wagner ◽  
Lars Frings ◽  
Ansgar Quiske ◽  
Josef Unterrainer ◽  
Ralf Schwarzwald ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Memory Task ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Verbal Episodic Memory

scholarly journals Memorable navigation: Assessing the influence of way-finding in spatial clustering

2020 ◽  
Author(s):  
Alvaro Pastor
Keyword(s):  
Cognitive Abilities ◽  
Spatial Information ◽  
Spatial Clustering ◽  
Recall Performance ◽  
Memory Task ◽  
Correct Recall ◽  
Brain Regions ◽  
Medial Temporal Lobes ◽  
Temporal Lobes

Navigating around an environment and remembering the events that took place within it are crucial cognitive abilities that have been linked to the Hippocampus and medial temporal lobes (MTL). Scene Construction Theory (SCT) has proposed that a function of the Hippocampus is the implicit and continuous construction of scenes to help prediction of upcoming environment. Scenes, as highly efficient means of packaging information, underpin in coordination with other brain regions, episodic memory (EM), spatial navigation, future thinking and perhaps even dreaming and mind-wandering. We examined the conditions in which spatial contiguity of stimuli influences the organization of memory by examining spatial clustering (SC) phenomenon. In this research, an augmented reality (AR) system was used to test 14 participants in a spatially dependent memory task which assessed the SC differences between active navigators and passive spectators. We confirmed our hypothesis that navigators use spatial information as part of the retrieval process in free recall, as they tended to sequentially recall any two neighboring otherwise unrelated items. We also found a significant correlation between SC and correct recall performance supporting our second hypothesis. These results may be valuable for design of learning applications, especially dealing with large amounts of data. Research on Alzheimer's and other neurodegenerative diseases may also benefit from our approach. Future studies may assess the role of encoding and retrieval modality and participant's use of mnemonic strategies.

scholarly journals Extradural Motor Cortex Stimulation might improve episodic and working memory in patients with Parkinson’s disease

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Carla Piano ◽  
Marco Ciavarro ◽  
Francesco Bove ◽  
Daniela Di Giuda ◽  
Fabrizio Cocciolillo ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Working Memory ◽  
Parkinson's Disease ◽  
Motor Cortex ◽  
Episodic Memory ◽  
Memory Task ◽  
Motor Symptoms ◽  
Motor Cortex Stimulation ◽  
Short Term ◽  
Verbal Episodic Memory

Abstract Electric Extradural Motor Cortex Stimulation (EMCS) is a neurosurgical procedure suggested for treatment of patients with advanced Parkinson’s disease (PD). We report two PD patients treated by EMCS, who experienced worsening of motor symptoms and cognition 5 years after surgery, when EMCS batteries became discharged. One month after EMCS restoration, they experienced a subjective improvement of motor symptoms and cognition. Neuropsychological assessments were carried out before replacement of batteries (off-EMCS condition) and 6 months afterward (on-EMCS condition). As compared to off-EMCS condition, in on-EMCS condition both patients showed an improvement on tasks of verbal episodic memory and backward spatial short-term/working memory task, and a decline on tasks of selective visual attention and forward spatial short-term memory. These findings suggest that in PD patients EMCS may induce slight beneficial effects on motor symptoms and cognitive processes involved in verbal episodic memory and in active manipulation of information stored in working memory.

scholarly journals Delay-dependent contributions of medial temporal lobe regions to episodic memory retrieval

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Maureen Ritchey ◽  
Maria E Montchal ◽  
Andrew P Yonelinas ◽  
Charan Ranganath
Keyword(s):  
Episodic Memory ◽  
Medial Temporal Lobe ◽  
Functional Neuroimaging ◽  
Contextual Information ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Pattern Similarity ◽  
Delayed Recognition ◽  
Delay Dependent ◽  
Over Time

The medial temporal lobes play an important role in episodic memory, but over time, hippocampal contributions to retrieval may be diminished. However, it is unclear whether such changes are related to the ability to retrieve contextual information, and whether they are common across all medial temporal regions. Here, we used functional neuroimaging to compare neural responses during immediate and delayed recognition. Results showed that recollection-related activity in the posterior hippocampus declined after a 1-day delay. In contrast, activity was relatively stable in the anterior hippocampus and in neocortical areas. Multi-voxel pattern similarity analyses also revealed that anterior hippocampal patterns contained information about context during item recognition, and after a delay, context coding in this region was related to successful retention of context information. Together, these findings suggest that the anterior and posterior hippocampus have different contributions to memory over time and that neurobiological models of memory must account for these differences.

Verbal Learning and Memory Enhancement Strategies in Schizophrenia: A Randomized, Controlled Investigation

2017 ◽  
Vol 23 (4) ◽  
pp. 352-357 ◽  
Author(s):  
Matthew M. Kurtz ◽  
Christi L. Trask ◽  
Rachel Rosengard ◽  
Simone Hyman ◽  
Lisa Kremen ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Verbal Memory ◽  
Verbal Learning ◽  
Memory Task ◽  
Word List ◽  
Narrative Structure ◽  
Strategy Training ◽  
Word Recall ◽  
Mnemonic Strategy ◽  
Verbal Episodic Memory

AbstractObjectives: Verbal episodic memory is a key domain of impairment in people with schizophrenia with close ties to a variety of aspects of functioning and therapeutic treatment response. A randomized, blinded trial of two mnemonic strategies for verbal episodic memory deficits for people with schizophrenia was conducted. Methods: Sixty-one people with schizophrenia were assigned to one of three experimental conditions: training in a mnemonic strategy that included both visualization and narrative structure (Story Method), a condition in which participants were trained to visualize words interacting with one another (Imagery), or a non-trained control condition in which participants received equivalent exposure to training word lists and other verbal memory assessments administered in the other two conditions, but without provision of any compensatory mnemonic strategy. Participants were assessed on improvements in recall of the word list used as part of training, as well as two, standardized verbal memory assessments which included stimuli not used as part of strategy training. Results: The Story Method produced improvements on a trained word list that generalized to a non-trained, prose memory task at a 1-week follow-up. In contrast, provision of a mnemonic strategy of simple visualization of words produced little improvement on word recall of trained words or on measures of generalization relative to the performance of participants in the control condition. Conclusions: These findings support the inclusion of enriched mnemonic strategies consisting of both visualization and narrative structure in sustained and comprehensive programs of CR for enhancement of verbal episodic memory in schizophrenia. (JINS, 2017, 23, 352–357)

scholarly journals Neural Correlates of Confidence during Item Recognition and Source Memory Retrieval: Evidence for Both Dual-process and Strength Memory Theories

2011 ◽  
Vol 23 (12) ◽  
pp. 3959-3971 ◽  
Author(s):  
Scott M. Hayes ◽  
Norbou Buchler ◽  
Jared Stokes ◽  
James Kragel ◽  
Roberto Cabeza
Keyword(s):  
Episodic Memory ◽  
Source Memory ◽  
Memory Retrieval ◽  
Memory Task ◽  
Dual Process ◽  
Item Memory ◽  
Strength Theory ◽  
High Confidence ◽  
Medial Temporal Lobes ◽  
Memory Network

Although the medial-temporal lobes (MTL), PFC, and parietal cortex are considered primary nodes in the episodic memory network, there is much debate regarding the contributions of MTL, PFC, and parietal subregions to recollection versus familiarity (dual-process theory) and the feasibility of accounts on the basis of a single memory strength process (strength theory). To investigate these issues, the current fMRI study measured activity during retrieval of memories that differed quantitatively in terms of strength (high vs. low-confidence trials) and qualitatively in terms of recollection versus familiarity (source vs. item memory tasks). Support for each theory varied depending on which node of the episodic memory network was considered. Results from MTL best fit a dual-process account, as a dissociation was found between a right hippocampal region showing high-confidence activity during the source memory task and bilateral rhinal regions showing high-confidence activity during the item memory task. Within PFC, several left-lateralized regions showed greater activity for source than item memory, consistent with recollective orienting, whereas a right-lateralized ventrolateral area showed low-confidence activity in both tasks, consistent with monitoring processes. Parietal findings were generally consistent with strength theory, with dorsal areas showing low-confidence activity and ventral areas showing high-confidence activity in both tasks. This dissociation fits with an attentional account of parietal functions during episodic retrieval. The results suggest that both dual-process and strength theories are partly correct, highlighting the need for an integrated model that links to more general cognitive theories to account for observed neural activity during episodic memory retrieval.

scholarly journals Theories of episodic memory

2001 ◽  
Vol 356 (1413) ◽  
pp. 1395-1408 ◽  
Author(s):  
Andrew R. Mayes ◽  
Neil Roberts
Keyword(s):  
Episodic Memory ◽  
Medial Temporal Lobe ◽  
Functional Neuroimaging ◽  
Memory Storage ◽  
Visual Object ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Episodic Information ◽  
Encoding And Retrieval

Theories of episodic memory need to specify the encoding (representing), storage, and retrieval processes that underlie this form of memory and indicate the brain regions that mediate these processes and how they do so. Representation and re–representation (retrieval) of the spatiotemporally linked series of scenes, which constitute an episode, are probably mediated primarily by those parts of the posterior neocortex that process perceptual and semantic information. However, some role of the frontal neocortex and medial temporal lobes in representing aspects of context and high–level visual object information at encoding and retrieval cannot currently be excluded. Nevertheless, it is widely believed that the frontal neocortex is mainly involved in coordinating episodic encoding and retrieval and that the medial temporal lobes store aspects of episodic information. Establishing where storage is located is very difficult and disagreement remains about the role of the posterior neocortex in episodic memory storage. One view is that this region stores all aspects of episodic memory ab initio for as long as memory lasts. This is compatible with evidence that the amygdala, basal forebrain, and midbrain modulate neocortical storage. Another view is that the posterior neocortex only gradually develops the ability to store some aspects of episodic information as a function of rehearsal over time and that this information is initially stored by the medial temporal lobes. A third view is that the posterior neocortex never stores these aspects of episodic information because the medial temporal lobes store them for as long as memory lasts in an increasingly redundant fashion. The last two views both postulate that the medial temporal lobes initially store contextual markers that serve to cohere featural information stored in the neocortex. Lesion and functional neuroimaging evidence still does not clearly distinguish between these views. Whether the feeling that an episodic memory is familiar depends on retrieving an association between a retrieved episode and this feeling, or by an attribution triggered by a priming process, is unclear. Evidence about whether the hippocampus and medial temporal lobe cortices play different roles in episodic memory is conflicting. Identifying similarities and differences between episodic memory and both semantic memory and priming will require careful componential analysis of episodic memory.

Recall, recognition, and the medial temporal lobes

1999 ◽  
Vol 22 (3) ◽  
pp. 455-456 ◽  
Author(s):  
Barbara J. Knowlton
Keyword(s):  
Episodic Memory ◽  
Current Evidence ◽  
Medial Temporal Lobes ◽  
Temporal Lobes

Aggleton & Brown predict that recognition and episodic recall depend on different brain systems and can thus be dissociated from one another. However, intact recall with impaired recognition has not yet been demonstrated if the same type of information is used in both tests. Current evidence suggests that processes underlying familiarity-based recognition are redundant with processes underlying episodic memory.

scholarly journals No Effect of Anodal tDCS on Verbal Episodic Memory Performance and Neurotransmitter Levels in Young and Elderly Participants

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Annegret Habich ◽  
Johannes Slotboom ◽  
Jessica Peter ◽  
Roland Wiest ◽  
Stefan Klöppel
Keyword(s):  
Episodic Memory ◽  
Memory Task ◽  
Resonance Spectroscopy ◽  
Cortical Region ◽  
Anodal Tdcs ◽  
Memory Processes ◽  
Baseline Performance ◽  
Left Dlpfc ◽  
Neurophysiological Mechanisms ◽  
Verbal Episodic Memory

Healthy ageing is accompanied by cognitive decline that affects episodic memory processes in particular. Studies showed that anodal transcranial direct current stimulation (tDCS) to the left dorsolateral prefrontal cortex (DLPFC) may counteract this cognitive deterioration by increasing excitability and inducing neuroplasticity in the targeted cortical region. While stimulation gains are more consistent in initial low performers, relying solely on behavioural measures to predict treatment benefits does not suffice for a reliable implementation of this method as a therapeutic option. Hence, an exploration of the underlying neurophysiological mechanisms regarding the differential stimulation effect is warranted. Glutamatergic metabolites (Glx) and γ-aminobutyric acid (GABA) are involved in learning and memory processes and can be influenced with tDCS; wherefore, they present themselves as potential biomarkers for tDCS-induced behavioural gains, which are affiliated with neuroplasticity processes. In the present randomized, double-blind, sham-controlled, crossover study, 33 healthy young and 22 elderly participants received anodal tDCS to their left DLPFC during the encoding phase of a verbal episodic memory task. Using MEGA-PRESS edited magnetic resonance spectroscopy (MRS), Glx and GABA levels were measured in the left DLPFC before and after the stimulation period. Further, we tested whether baseline performance and neurotransmitter levels predicted subsequent gains. No beneficial group effects of tDCS emerged in either verbal retrieval performances or neurotransmitter concentrations. Moreover, baseline performance levels did not predict stimulation-induced cognitive gains, nor did Glx or GABA levels. Nevertheless, exploratory analyses suggested a predictive value of the Glx : GABA ratio, with lower ratios at baseline indicating greater tDCS-related gains in delayed recall performance. This highlights the importance of further studies investigating neurophysiological mechanisms underlying previously observed stimulation-induced cognitive benefits and their respective interindividual heterogeneity.

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