scholarly journals Functional interactions between the medial temporal lobes and posterior neocortex related to episodic memory retrieval

1998 ◽  
Vol 8 (5) ◽  
pp. 451-461 ◽  
Author(s):  
S. Kohler ◽  
A. R. McIntosh ◽  
M. Moscovitch ◽  
G. Winocur
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Functional Interactions

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.

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 Preservation of episodic memory in semantic dementia: The importance of regions beyond the medial temporal lobes

2016 ◽  
Vol 81 ◽  
pp. 50-60 ◽  
Author(s):  
Muireann Irish ◽  
Steffie Bunk ◽  
Sicong Tu ◽  
Jody Kamminga ◽  
John R. Hodges ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Semantic Dementia ◽  
Medial Temporal Lobes ◽  
Temporal Lobes

scholarly journals A causal role for the precuneus in network-wide theta and gamma oscillatory activity during complex memory retrieval

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Melissa Hebscher ◽  
Jed A Meltzer ◽  
Asaf Gilboa
Keyword(s):  
Memory Retrieval ◽  
Rest Period ◽  
Gamma Oscillations ◽  
Oscillatory Activity ◽  
Medial Temporal Lobes ◽  
Network Nodes ◽  
Temporal Lobes ◽  
Oscillatory Coupling ◽  
Phase Amplitude ◽  
Cortical Representations

Complex memory of personal events is thought to depend on coordinated reinstatement of cortical representations by the medial temporal lobes (MTL). MTL-cortical theta and gamma coupling is believed to mediate such coordination, but which cortical structures are critical for retrieval and how they influence oscillatory coupling is unclear. We used magnetoencephalography (MEG) combined with continuous theta burst stimulation (cTBS) to (i) clarify the roles of theta and gamma oscillations in network-wide communication during naturalistic memory retrieval, and (ii) understand the causal relationship between cortical network nodes and oscillatory communication. Retrieval was associated with MTL-posterior neocortical theta phase coupling and theta-gamma phase-amplitude coupling relative to a rest period. Precuneus cTBS altered MTL-neocortical communication by modulating theta and gamma oscillatory coupling. These findings provide a mechanistic account for MTL-cortical communication and demonstrate that the precuneus is a critical cortical node of oscillatory activity, coordinating cross-regional interactions that drive remembering.

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