scholarly journals Tracking the relation between gist and item memory over the course of long-term memory consolidation

2021 ◽  
Author(s):  
Tima Zeng ◽  
Alexa Tompary ◽  
Anna C. Schapiro ◽  
Sharon L. Thompson-Schill
Keyword(s):  
Memory Consolidation ◽  
Item Memory ◽  
Long Term Memory ◽  
Local Center ◽  
Term Memory ◽  
The World ◽  
Human Participants ◽  
Spatial Locations ◽  
Over Time

AbstractOur experiences in the world support memories not only of specific episodes but also of the generalities (the ‘gist’) across related experiences. It remains unclear how these two types of memories evolve and influence one another over time. 173 human participants encoded spatial locations from a distribution and reported both item memory (specific locations) and gist memory (center for the locations) across one to two months. After one month, gist memory was preserved relative to item memory, despite a persistent positive correlation between them. Critically, item memories were biased towards the gist over time; however, with a spatial outlier item, the local center excluding the outlier became the source of bias, instead of the reported center overweighting the outlier. Our results suggest that the extraction of gist is sensitive to the regularities of items, and that the gist starts to guide item memories over longer durations as their relative strengths change.

scholarly journals Tracking the relation between gist and item memory over the course of long-term memory consolidation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Tima Zeng ◽  
Alexa Tompary ◽  
Anna C Schapiro ◽  
Sharon Thompson-Schill
Keyword(s):  
Memory Consolidation ◽  
Item Memory ◽  
Long Term Memory ◽  
Term Memory ◽  
Spatial Outlier ◽  
The World ◽  
Human Participants ◽  
Spatial Locations ◽  
Over Time

Our experiences in the world support memories not only of specific episodes but also of the generalities (the ‘gist’) across related experiences. It remains unclear how these two types of memories evolve and influence one another over time. In two experiments, 173 human participants encoded spatial locations from a distribution and reported both item memory (specific locations) and gist memory (center for the locations) across one to two months. Experiment 1 demonstrated that after one month, gist memory was preserved relative to item memory, despite a persistent positive correlation between them. Critically, item memories were biased towards the gist over time. Experiment 2 showed that a spatial outlier item changed this relationship and that the extraction of gist is sensitive to the regularities of items. Our results suggest that the gist starts to guide item memories over longer durations as their relative strengths change.

Notch signalling becomes transiently attenuated during long-term memory consolidation in adult Wistar rats

2007 ◽  
Vol 88 (3) ◽  
pp. 342-351 ◽  
Author(s):  
Lisa Conboy ◽  
Claire M. Seymour ◽  
Marco P. Monopoli ◽  
Niamh C. O’Sullivan ◽  
Keith J. Murphy ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Wistar Rats ◽  
Notch Signalling ◽  
Long Term Memory ◽  
Term Memory

scholarly journals COMPLEXITY-BASED ANALYSIS OF THE ALTERATIONS IN THE STRUCTURE OF CORONAVIRUSES

Fractals ◽  
2021 ◽  
Vol 29 (02) ◽  
pp. 2150123
Author(s):  
HAMIDREZA NAMAZI ◽  
ALI SELAMAT ◽  
ONDREJ KREJCAR
Keyword(s):  
Hurst Exponent ◽  
Complex Structure ◽  
Approximate Entropy ◽  
Sample Entropy ◽  
Long Term Memory ◽  
Complex Structures ◽  
Term Memory ◽  
The World ◽  
First Time

The coronavirus has influenced the lives of many people since its identification in 1960. In general, there are seven types of coronavirus. Although some types of this virus, including 229E, NL63, OC43, and HKU1, cause mild to moderate illness, SARS-CoV, MERS-CoV, and SARS-CoV-2 have shown to have severer effects on the human body. Specifically, the recent known type of coronavirus, SARS-CoV-2, has affected the lives of many people around the world since late 2019 with the disease named COVID-19. In this paper, for the first time, we investigated the variations among the complex structures of coronaviruses. We employed the fractal dimension, approximate entropy, and sample entropy as the measures of complexity. Based on the obtained results, SARS-CoV-2 has a significantly different complex structure than SARS-CoV and MERS-CoV. To study the high mutation rate of SARS-CoV-2, we also analyzed the long-term memory of genome walks for different coronaviruses using the Hurst exponent. The results demonstrated that the SARS-CoV-2 shows the lowest memory in its genome walk, explaining the errors in copying the sequences along the genome that results in the virus mutation.

Manifold Visual Working Memory

2020 ◽  
pp. 311-332
Author(s):  
Nicole Hakim ◽  
Edward Awh ◽  
Edward K. Vogel
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Neural Activity ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Representations ◽  
Latent Representations ◽  
Definition Of ◽  
Spatial Locations

Visual working memory allows us to maintain information in mind for use in ongoing cognition. Research on visual working memory often characterizes it within the context of its interaction with long-term memory (LTM). These embedded-processes models describe memory representations as existing in three potential states: inactivated LTM, including all representations stored in LTM; activated LTM, latent representations that can quickly be brought into an active state due to contextual priming or recency; and the focus of attention, an active but sharply limited state in which only a small number of items can be represented simultaneously. This chapter extends the embedded-processes framework of working memory. It proposes that working memory should be defined operationally based on neural activity. By defining working memory in this way, the important theoretical distinction between working memory and LTM is maintained, while still acknowledging that they operate together. It is additionally proposed that active working memory should be further subdivided into at least two subcomponent processes that index item-based storage and currently prioritized spatial locations. This fractionation of working memory is based on recent research that has found that the maintenance of information distinctly relies on item-based representations as well as prioritization of spatial locations. It is hoped that this updated framework of the definition of working memory within the embedded-processes model provides further traction for understanding how we maintain information in mind.

scholarly journals The amnestic agent anisomycin disrupts intrinsic membrane properties of hippocampal neurons via a loss of cellular energetics

2019 ◽  
Vol 122 (3) ◽  
pp. 1123-1135 ◽  
Author(s):  
C. J. Scavuzzo ◽  
M. J. LeBlancq ◽  
F. Nargang ◽  
H. Lemieux ◽  
T. J. Hamilton ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Mitochondrial Function ◽  
Neural Activity ◽  
Memory Consolidation ◽  
Hippocampal Neurons ◽  
Membrane Properties ◽  
Long Term Memory ◽  
Term Memory ◽  
Cellular Energetics

The nearly axiomatic idea that de novo protein synthesis is necessary for long-term memory consolidation is based heavily on behavioral studies using translational inhibitors such as anisomycin. Although inhibiting protein synthesis has been shown to disrupt the expression of memory, translational inhibitors also have been found to profoundly disrupt basic neurobiological functions, including the suppression of ongoing neural activity in vivo. In the present study, using transverse hippocampal brain slices, we monitored the passive and active membrane properties of hippocampal CA1 pyramidal neurons using intracellular whole cell recordings during a brief ~30-min exposure to fast-bath-perfused anisomycin. Anisomycin suppressed protein synthesis to 46% of control levels as measured using incorporation of radiolabeled amino acids and autoradiography. During its application, anisomycin caused a significant depolarization of the membrane potential, without any changes in apparent input resistance or membrane time constant. Anisomycin-treated neurons also showed significant decreases in firing frequencies and spike amplitudes, and showed increases in spike width across spike trains, without changes in spike threshold. Because these changes indicated a loss of cellular energetics contributing to maintenance of ionic gradients across the membrane, we confirmed that anisomycin impaired mitochondrial function by reduced staining with 2,3,5-triphenyltetrazolium chloride and also impaired cytochrome c oxidase (complex IV) activity as indicated through high-resolution respirometry. These findings emphasize that anisomycin-induced alterations in neural activity and metabolism are a likely consequence of cell-wide translational inhibition. Critical reevaluation of studies using translational inhibitors to promote the protein synthesis dependent idea of long-term memory is absolutely necessary. NEW & NOTEWORTHY Memory consolidation is thought to be dependent on the synthesis of new proteins because translational inhibitors produce amnesia when administered just after learning. However, these agents also disrupt basic neurobiological functions. We show that blocking protein synthesis disrupts basic membrane properties of hippocampal neurons that correspond to induced disruptions of mitochondrial function. It is likely that translational inhibitors cause amnesia through their disruption of neural activity as a result of dysfunction of intracellular energetics.

scholarly journals The Medial Temporal Lobe Is Critical for Spatial Relational Perception

2020 ◽  
Vol 32 (9) ◽  
pp. 1780-1795 ◽  
Author(s):  
Nicholas A. Ruiz ◽  
Michael R. Meager ◽  
Sachin Agarwal ◽  
Mariam Aly
Keyword(s):  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Critical Role ◽  
Long Term Memory ◽  
Term Memory ◽  
Cognitive Domains ◽  
Attention Tasks ◽  
Human Participants ◽  
Attention And Perception

The medial temporal lobe (MTL) is traditionally considered to be a system that is specialized for long-term memory. Recent work has challenged this notion by demonstrating that this region can contribute to many domains of cognition beyond long-term memory, including perception and attention. One potential reason why the MTL (and hippocampus specifically) contributes broadly to cognition is that it contains relational representations—representations of multidimensional features of experience and their unique relationship to one another—that are useful in many different cognitive domains. Here, we explore the hypothesis that the hippocampus/MTL plays a critical role in attention and perception via relational representations. We compared human participants with MTL damage to healthy age- and education-matched individuals on attention tasks that varied in relational processing demands. On each trial, participants viewed two images (rooms with paintings). On “similar room” trials, they judged whether the rooms had the same spatial layout from a different perspective. On “similar art” trials, they judged whether the paintings could have been painted by the same artist. On “identical” trials, participants simply had to detect identical paintings or rooms. MTL lesion patients were significantly and selectively impaired on the similar room task. This work provides further evidence that the hippocampus/MTL plays a ubiquitous role in cognition by virtue of its relational and spatial representations and highlights its important contributions to rapid perceptual processes that benefit from attention.

scholarly journals Individual Differences in Learning Efficiency

2019 ◽  
Vol 28 (6) ◽  
pp. 607-613
Author(s):  
Kathleen B. McDermott ◽  
Christopher L. Zerr
Keyword(s):  
Individual Differences ◽  
Experimental Approach ◽  
Long Term Memory ◽  
Positive Relation ◽  
Future Directions ◽  
Term Memory ◽  
Learning Efficiency ◽  
Rate Of Learning ◽  
Over Time

Most research on long-term memory uses an experimental approach whereby participants are assigned to different conditions, and condition means are the measures of interest. This approach has demonstrated repeatedly that conditions that slow the rate of learning tend to improve later retention. A neglected question is whether aggregate findings at the level of the group (i.e., slower learning tends to improve retention) translate to the level of individual people. We identify a discrepancy whereby—across people—slower learning tends to coincide with poorer memory. The positive relation between learning rate (speed of learning) and retention (amount remembered after a delay) across people is referred to as learning efficiency. A more efficient learner can acquire information faster and remember more of it over time. We discuss potential characteristics of efficient learners and consider future directions for research.

Evidence for two distinct sleep-related long-term memory consolidation processes

Cortex ◽  
2015 ◽  
Vol 63 ◽  
pp. 68-78 ◽  
Author(s):  
Monika Schönauer ◽  
Melanie Grätsch ◽  
Steffen Gais
Keyword(s):  
Memory Consolidation ◽  
Long Term Memory ◽  
Term Memory
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