Memory systems, frontal cortex, and the hippocampal axis

1999 ◽  
Vol 22 (3) ◽  
pp. 464-465 ◽  
Author(s):  
Amanda Parker
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Frontal Cortex ◽  
Experimental Evidence ◽  
Memory Systems ◽  
Mediodorsal Thalamus ◽  
And Storage

Three comments are made. The proposal that recollection and familiarity-based recognition take different thalamic routes does not fit recent experimental evidence, suggesting that mediodorsal thalamus acts in an integrative role with respect to prefrontal cortex. Second, the role of frontal cortex in episodic memory has been understated. Third, the role of the hippocampal axis is likely to be the computation and storage of ideothetic information.

A Scene-Based Episodic Memory System for a Simulated Autonomous Creature

2013 ◽  
Vol 4 (1) ◽  
pp. 32-64 ◽  
Author(s):  
Elisa C. Castro ◽  
Ricardo R. Gudwin
Keyword(s):  
Episodic Memory ◽  
Navigation System ◽  
Cognitive Architecture ◽  
Human Memory ◽  
Memory Systems ◽  
Memory Module ◽  
The Past ◽  
3D Environment ◽  
Main Ideas

In this paper the authors present the development of a scene-based episodic memory module for the cognitive architecture controlling an autonomous virtual creature, in a simulated 3D environment. The scene-based episodic memory has the role of improving the creature’s navigation system, by evoking the objects to be considered in planning, according to episodic remembrance of earlier scenes testified by the creature where these objects were present in the past. They introduce the main background on human memory systems and episodic memory study, and provide the main ideas behind the experiment.

THE ROLE OF DOPAMINE IN THE MAINTENANCE OF WORKING MEMORY IN PREFRONTAL CORTEX NEURONS: INPUT-DRIVEN VERSUS INTERNALLY-DRIVEN NETWORKS

2010 ◽  
Vol 20 (04) ◽  
pp. 249-265 ◽  
Author(s):  
MASSIMILIANO VERSACE ◽  
MARCO ZORZI
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Sensory Input ◽  
Memory Task ◽  
Biologically Inspired ◽  
Sustained Activity ◽  
Continuous Stream ◽  
And Storage ◽  
Relevant Pattern

How do organisms select and organize relevant sensory input in working memory (WM) in order to deal with constantly changing environmental cues? Once information has been stored in WM, how is it protected from and altered by the continuous stream of sensory input and internally generated planning? The present study proposes a novel role for dopamine (DA) in the maintenance of WM in the prefrontal cortex (Pfc) neurons that begins to address these issues. In particular, DA mediates the alternation of the Pfc network between input-driven and internally-driven states, which in turn drives WM updates and storage. A biologically inspired neural network model of Pfc is formulated to provide a link between the mechanisms of state switching and the biophysical properties of Pfc neurons. This model belongs to the recurrent competitive fields33 class of dynamical systems which have been extensively mathematically characterized and exhibit the two functional states of interest: input-driven and internally-driven. This hypothesis was tested with two working memory tasks of increasing difficulty: a simple working memory task and a delayed alternation task. The results suggest that optimal WM storage in spite of noise is achieved with a phasic DA input followed by a lower DA sustained activity. Hypo and hyper-dopaminergic activity that alter this ideal pattern lead to increased distractibility from non-relevant pattern and prolonged perseverations on presented patterns, respectively.

Role of the prefrontal cortex in human episodic memory: Lessons from PET studies

1997 ◽  
Vol 42 (1) ◽  
pp. 75S-76S ◽  
Author(s):  
S. Kapur ◽  
F.I.M. Craik ◽  
E. Tulving ◽  
S. Houle
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory

scholarly journals Evidence for an Active Role of Inferior Frontal Cortex in Conscious Experience

2020 ◽  
Author(s):  
Veith Weilnhammer ◽  
Merve Fritsch ◽  
Meera Chikermane ◽  
Anna-Lena Eckert ◽  
Katharina Kanthak ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Frontal Cortex ◽  
Conscious Experience ◽  
Sensory Information ◽  
Active Role ◽  
Neural Correlates ◽  
Functional Magnetic Resonance ◽  
Bistable Perception ◽  
Inferior Frontal Cortex

2AbstractIn the search for the neural correlates of consciousness, it has remained controversial whether prefrontal cortex determines what is consciously experienced or, alternatively, serves only complementary functions such as introspection or action.Here, we provide converging evidence from computational modeling and two functional magnetic resonance imaging experiments for a key role of inferior frontal cortex in detecting perceptual conflicts that emerge from ambiguous sensory information. Crucially, the detection of perceptual conflicts by prefrontal cortex turned out to be critical in the process of transforming ambiguous sensory information into unambiguous conscious experiences: In a third experiment, disruption of neural activity in inferior frontal cortex through transcranial magnetic stimulation slowed down the updating of conscious experience that occurs in response to perceptual conflicts.These findings show that inferior frontal cortex actively contributes to the resolution of perceptual ambiguities. Prefrontal cortex is thus causally involved in determining the contents of conscious experience.3One-sentence SummaryInferior frontal cortex detects and resolves perceptual conflict during bistable perception.

scholarly journals Dentate Gyrus Somatostatin Cells are Required for Contextual Discrimination During Episodic Memory Encoding

2020 ◽  
Author(s):  
Cristian Morales ◽  
Juan Facundo Morici ◽  
Nelson Espinosa ◽  
Agostina Sacson ◽  
Ariel Lara-Vasquez ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Dentate Gyrus ◽  
Granule Cells ◽  
Memory Systems ◽  
Pattern Separation ◽  
Activity Levels ◽  
Connection Probability ◽  
Somatostatin Cells ◽  
Formation Pattern

Abstract Memory systems ought to store and discriminate representations of similar experiences in order to efficiently guide future decisions. This problem is solved by pattern separation, implemented in the dentate gyrus (DG) by granule cells to support episodic memory formation. Pattern separation is enabled by tonic inhibitory bombardment generated by multiple GABAergic cell populations that strictly maintain low activity levels in granule cells. Somatostatin-expressing cells are one of those interneuron populations, selectively targeting the distal dendrites of granule cells, where cortical multimodal information reaches the DG. Nonetheless, somatostatin cells have very low connection probability and synaptic efficacy with both granule cells and other interneuron types. Hence, the role of somatostatin cells in DG circuitry, particularly in the context of pattern separation, remains uncertain. Here, by using optogenetic stimulation and behavioral tasks in mice, we demonstrate that somatostatin cells are required for the acquisition of both contextual and spatial overlapping memories.

scholarly journals Cognitive Control of Episodic Memory in Schizophrenia: Differential Role of Dorsolateral and Ventrolateral Prefrontal Cortex

2015 ◽  
Vol 9 ◽  
Author(s):  
John D. Ragland ◽  
Charan Ranganath ◽  
Joshua Phillips ◽  
Megan A. Boudewyn ◽  
Ann M. Kring ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Cognitive Control ◽  
Episodic Memory ◽  
Ventrolateral Prefrontal Cortex

scholarly journals The Medial Prefrontal Cortex and Fear Memory: Dynamics, Connectivity, and Engrams

2021 ◽  
Vol 22 (22) ◽  
pp. 12113
Author(s):  
Lucie Dixsaut ◽  
Johannes Gräff
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Memory Formation ◽  
Memory Storage ◽  
Long Term Memory ◽  
Brain Areas ◽  
Long Term Storage ◽  
And Storage

It is becoming increasingly apparent that long-term memory formation relies on a distributed network of brain areas. While the hippocampus has been at the center of attention for decades, it is now clear that other regions, in particular the medial prefrontal cortex (mPFC), are taking an active part as well. Recent evidence suggests that the mPFC—traditionally implicated in the long-term storage of memories—is already critical for the early phases of memory formation such as encoding. In this review, we summarize these findings, relate them to the functional importance of the mPFC connectivity, and discuss the role of the mPFC during memory consolidation with respect to the different theories of memory storage. Owing to its high functional connectivity to other brain areas subserving memory formation and storage, the mPFC emerges as a central hub across the lifetime of a memory, although much still remains to be discovered.

scholarly journals The Role of Prefrontal Cortex in Verbal Episodic Memory: rTMS Evidence

2003 ◽  
Vol 15 (6) ◽  
pp. 855-861 ◽  
Author(s):  
Marco Sandrini ◽  
Stefano F. Cappa ◽  
Simone Rossi ◽  
Paolo M. Rossini ◽  
Carlo Miniussi
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Phase Retrieval ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Unrelated Word ◽  
Study Phase ◽  
Memory Processing ◽  
Dorsolateral Prefrontal ◽  
The Right

Long-term, episodic memory processing is supposed to involve the prefrontal cortex asymmetrically. Here we investigate the role of the dorsolateral prefrontal cortex (DLPFC) in encoding and retrieval of semantically related or unrelated word pairs. Subjects were required to perform a task consisting of two parts: a study phase (encoding), in which word pairs were presented, and a test phase (retrieval), during which stimuli previously presented had to be recognized among other stimuli. Consistently with our previous findings using pictures, repetitive transcranial magnetic stimulation (rTMS) had a significant impact on episodic memory. The performance was significantly disrupted when rTMS was applied to the left or right DLPFC during encoding, and to the right DLPFC in retrieval, but only for unrelated word pairs. These results indicate that the nature of the material to be remembered interacts with the encoding–retrieval DLPFC asymmetry; moreover, the crucial role of DLPFC is evident only for novel stimuli.

scholarly journals The Role of Hippocampal–Ventromedial Prefrontal Cortex Neural Dynamics in Building Mental Representations

2021 ◽  
Vol 33 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Anna M. Monk ◽  
Marshall A. Dalton ◽  
Gareth R. Barnes ◽  
Eleanor A. Maguire
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Brain Regions ◽  
Ventromedial Prefrontal Cortex ◽  
High Temporal Resolution ◽  
Cognitive Domains ◽  
Initial Stage ◽  
Hippocampal Activity ◽  
Two Stages

The hippocampus and ventromedial prefrontal cortex (vmPFC) play key roles in numerous cognitive domains including mind-wandering, episodic memory, and imagining the future. Perspectives differ on precisely how they support these diverse functions, but there is general agreement that it involves constructing representations composed of numerous elements. Visual scenes have been deployed extensively in cognitive neuroscience because they are paradigmatic multielement stimuli. However, it remains unclear whether scenes, rather than other types of multifeature stimuli, preferentially engage hippocampus and vmPFC. Here, we leveraged the high temporal resolution of magnetoencephalography to test participants as they gradually built scene imagery from three successive auditorily presented object descriptions and an imagined 3-D space. This was contrasted with constructing mental images of nonscene arrays that were composed of three objects and an imagined 2-D space. The scene and array stimuli were, therefore, highly matched, and this paradigm permitted a closer examination of step-by-step mental construction than has been undertaken previously. We observed modulation of theta power in our two regions of interest—anterior hippocampus during the initial stage and vmPFC during the first two stages, of scene relative to array construction. Moreover, the scene-specific anterior hippocampal activity during the first construction stage was driven by the vmPFC, with mutual entrainment between the two brain regions thereafter. These findings suggest that hippocampal and vmPFC neural activity is especially tuned to scene representations during the earliest stage of their formation, with implications for theories of how these brain areas enable cognitive functions such as episodic memory.

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