The Prefrontal-Hippocampal Comparator: Volition and Episodic Memory

2021 ◽  
pp. 003151252110413
Author(s):  
Robert Numan
Keyword(s):  
Episodic Memory ◽  
Action Plan ◽  
Efference Copy ◽  
Corollary Discharge ◽  
Future Research ◽  
Hippocampal Area ◽  
Episodic Memories ◽  
Dependent Tasks ◽  
Hippocampal Theta ◽  
Goal Directed Behavior

This review describes recent research that is relevant to the prefrontal-hippocampal comparator model with the following conclusions: 1. Hippocampal area CA1 serves, at least in part, as an associative match-mismatch comparator. 2. Voluntary movement strengthens episodic memories for goal-directed behavior. 3. Hippocampal theta power serves as a prediction error signal during hippocampal dependent tasks. 4. The self-referential component of episodic memory in humans is mediated by the corollary discharge (the efference copy of the action plan developed by prefrontal cortex and transmitted to hippocampus where it is stored as a working memory; CA1 uses this efference copy to compare the expected consequences of action to the actual consequences of action). 5. Impairments in the production or transmission of this corollary discharge may contribute to some of the symptoms of schizophrenia. Unresolved issues and suggestions for future research are discussed.

scholarly journals The Prefrontal-Hippocampal Comparator: Volition and Episodic Memory

2021 ◽  
Author(s):  
Robert Numan
Keyword(s):  
Episodic Memory ◽  
Action Plan ◽  
Review Article ◽  
Corollary Discharge ◽  
Error Signal ◽  
Hippocampal Area ◽  
Episodic Memories ◽  
Dependent Tasks ◽  
Hippocampal Theta ◽  
Goal Directed Behavior

This review article supports the following: (1) Hippocampal area CA1 serves as an associative match-mismatch comparator, (2) Voluntary movement strengthens episodic memories for goal-directed behavior, (3) Hippocampal theta power serves as a prediction error signal during hippocampal dependent tasks, (4) The self-referential component of episodic memory in humans is mediated by the corollary discharge (efference copy of the action plan developed by prefrontal cortex), and (5) Impairments in the production or transmission of this corollary discharge may contribute to some of the symptoms of schizophrenia. <br>

scholarly journals The Prefrontal-Hippocampal Comparator: Volition and Episodic Memory

2021 ◽  
Author(s):  
Robert Numan
Keyword(s):  
Episodic Memory ◽  
Action Plan ◽  
Review Article ◽  
Corollary Discharge ◽  
Error Signal ◽  
Hippocampal Area ◽  
Episodic Memories ◽  
Dependent Tasks ◽  
Hippocampal Theta ◽  
Goal Directed Behavior

This review article supports the following: (1) Hippocampal area CA1 serves as an associative match-mismatch comparator, (2) Voluntary movement strengthens episodic memories for goal-directed behavior, (3) Hippocampal theta power serves as a prediction error signal during hippocampal dependent tasks, (4) The self-referential component of episodic memory in humans is mediated by the corollary discharge (efference copy of the action plan developed by prefrontal cortex), and (5) Impairments in the production or transmission of this corollary discharge may contribute to some of the symptoms of schizophrenia. <br>

scholarly journals Directional coupling of slow and fast hippocampal gamma with neocortical alpha/beta oscillations in human episodic memory

2019 ◽  
Vol 116 (43) ◽  
pp. 21834-21842 ◽  
Author(s):  
Benjamin J. Griffiths ◽  
George Parish ◽  
Frederic Roux ◽  
Sebastian Michelmann ◽  
Mircea van der Plas ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Memory Formation ◽  
Beta Power ◽  
Wide Range ◽  
Alpha Beta ◽  
Episodic Memories ◽  
Hippocampal Theta ◽  
Multisensory Information ◽  
Flow Of Information

Episodic memories hinge upon our ability to process a wide range of multisensory information and bind this information into a coherent, memorable representation. On a neural level, these 2 processes are thought to be supported by neocortical alpha/beta desynchronization and hippocampal theta/gamma synchronization, respectively. Intuitively, these 2 processes should couple to successfully create and retrieve episodic memories, yet this hypothesis has not been tested empirically. We address this by analyzing human intracranial electroencephalogram data recorded during 2 associative memory tasks. We find that neocortical alpha/beta (8 to 20 Hz) power decreases reliably precede and predict hippocampal “fast” gamma (60 to 80 Hz) power increases during episodic memory formation; during episodic memory retrieval, however, hippocampal “slow” gamma (40 to 50 Hz) power increases reliably precede and predict later neocortical alpha/beta power decreases. We speculate that this coupling reflects the flow of information from the neocortex to the hippocampus during memory formation, and hippocampal pattern completion inducing information reinstatement in the neocortex during memory retrieval.

scholarly journals Social Engagement and Episodic Memory in Non-Hispanic Black and White Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 343-343
Author(s):  
Abbey Hamlin ◽  
A Zarina Kraal ◽  
Laura Zahodne
Keyword(s):  
Social Support ◽  
Older Adults ◽  
Episodic Memory ◽  
Cognitive Aging ◽  
Social Engagement ◽  
Future Research ◽  
Social Activities ◽  
Linear Regression Models ◽  
Significant Positive Association ◽  
Cross Sectional

Abstract Social engagement may confer cognitive benefits in older adulthood, but studies have typically been restricted to largely non-Hispanic White (NHW) samples. Levels of social engagement vary across race such that NHW report larger social networks, more frequent participation in social activities, and greater social support than non-Hispanic Blacks (NHB). Associations between social engagement and cognition may also vary by race, but research is sparse. The current cross-sectional study examined associations between different aspects of social engagement and episodic memory performance, as well as interactions between social engagement and race among NHB and NHW participants in the Michigan Cognitive Aging Project (N = 247; 48.4% NHB; age = 64.19 ± 2.92). Social engagement (network size, activities, support) was self-reported. Episodic memory was a z-score composite of immediate, delayed, and recognition trials of a list-learning task. Separate hierarchical linear regression models quantified interactions between race and each of the three social engagement variables on episodic memory, controlling for sociodemographics, depressive symptoms, and health conditions. Results showed a main effect of more frequent social activity on better episodic memory, as well as an interaction between race and social support indicating a significant positive association in NHB but not NHW. These preliminary findings suggest that participating in social activities may be equally beneficial for episodic memory across NHB and NHW older adults and that social support may be particularly beneficial for NHB. Future research is needed to determine the potential applications of these results in reducing cognitive inequalities through the development of culturally-relevant interventions.

scholarly journals Bi-Temporal Anodal Transcranial Direct Current Stimulation during Slow-Wave Sleep Boosts Slow-Wave Density but Not Memory Consolidation

2021 ◽  
Vol 11 (4) ◽  
pp. 410
Author(s):  
Simon Ruch ◽  
Kristoffer Fehér ◽  
Stephanie Homan ◽  
Yosuke Morishima ◽  
Sarah Maria Mueller ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Slow Wave ◽  
Direct Current ◽  
Memory Consolidation ◽  
Transcranial Direct Current Stimulation ◽  
Slow Wave Sleep ◽  
Memory Performance ◽  
Direct Current Stimulation ◽  
Sleep Parameters ◽  
Episodic Memories

Slow-wave sleep (SWS) has been shown to promote long-term consolidation of episodic memories in hippocampo–neocortical networks. Previous research has aimed to modulate cortical sleep slow-waves and spindles to facilitate episodic memory consolidation. Here, we instead aimed to modulate hippocampal activity during slow-wave sleep using transcranial direct current stimulation in 18 healthy humans. A pair-associate episodic memory task was used to evaluate sleep-dependent memory consolidation with face–occupation stimuli. Pre- and post-nap retrieval was assessed as a measure of memory performance. Anodal stimulation with 2 mA was applied bilaterally over the lateral temporal cortex, motivated by its particularly extensive connections to the hippocampus. The participants slept in a magnetic resonance (MR)-simulator during the recordings to test the feasibility for a future MR-study. We used a sham-controlled, double-blind, counterbalanced randomized, within-subject crossover design. We show that stimulation vs. sham significantly increased slow-wave density and the temporal coupling of fast spindles and slow-waves. While retention of episodic memories across sleep was not affected across the entire sample of participants, it was impaired in participants with below-average pre-sleep memory performance. Hence, bi-temporal anodal direct current stimulation applied during sleep enhanced sleep parameters that are typically involved in memory consolidation, but it failed to improve memory consolidation and even tended to impair consolidation in poor learners. These findings suggest that artificially enhancing memory-related sleep parameters to improve memory consolidation can actually backfire in those participants who are in most need of memory improvement.

scholarly journals Event conjunction: How the hippocampus integrates episodic memories across event boundaries

2019 ◽  
Author(s):  
Benjamin James Griffiths ◽  
Lluís Fuentemilla
Keyword(s):  
Related Event ◽  
Gamma Model ◽  
Apparent Contradiction ◽  
The Past ◽  
Continuous Stream ◽  
Event Model ◽  
Episodic Memories ◽  
Hippocampal Theta ◽  
Conceptual Link ◽  
New Framework

Our lives are a continuous stream of experience. Our episodic memories, however, have a definitive beginning, middle and end. Theories of event segmentation suggest that salient changes in our environment produce event boundaries which partition the past from the present and, as a result, produce discretised memories. However, event boundaries cannot completely discretise two memories; any shared conceptual link will eagerly integrate these memories. Here, we present a new framework inspired by electrophysiological research that resolves this apparent contradiction. At its heart, the framework proposes that hippocampal theta-gamma coupling maintains a highly abstract model of an ongoing event and serves to encode this model as an episodic memory. When a second but related event begins, this theta-gamma model is rapidly reconstructed within the hippocampus where new details of the second event can be appended to the existing event model. The event conjunction framework is the first electrophysiological explanation of how event memories can be formed at, and integrated across, event boundaries.

scholarly journals When the Going Gets Tough, How Do We Perceive the Future?

2021 ◽  
Author(s):  
Stephanie J. Tepper ◽  
Neil Anthony Lewis
Keyword(s):  
Time Perception ◽  
Integrated Model ◽  
Future Research ◽  
Social And Behavioral Sciences ◽  
Behavioral Sciences ◽  
Intervention Practice ◽  
The Social ◽  
The Future ◽  
Goal Directed Behavior ◽  
Experienced Difficulty

People struggle to stay motivated to work toward difficult goals. Sometimes the feeling of difficulty signals that the goal is important and worth pursuing; other times, it signals that the goal is impossible and should be abandoned. In this paper, we argue that how difficulty is experienced depends on how we perceive and experience the timing of difficult events. We synthesize research from across the social and behavioral sciences and propose a new integrated model to explain how components of time perception interact with interpretations of experienced difficulty to influence motivation and goal-directed behavior. Although these constructs have been studied separately in previous research, we suggest that these factors are inseparable and that an integrated model will help us to better understand motivation and predict behavior. We conclude with new empirical questions to guide future research and by discussing the implications of this research for both theory and intervention practice.

scholarly journals Theta and gamma hippocampal-neocortical oscillations during the episodic-like memory test: impairment in epileptogenic rats

2021 ◽  
Author(s):  
Anton E Malkov ◽  
Ludmila Shevkova ◽  
Alexandra Latyshkova ◽  
Valentina Kitchigina
Keyword(s):  
Episodic Memory ◽  
Memory Task ◽  
Gamma Oscillations ◽  
High Amplitude ◽  
Memory Test ◽  
Interictal Spikes ◽  
Paroxysmal Activity ◽  
Cortical Oscillations ◽  
Gamma Rhythms ◽  
Hippocampal Theta

Cortical oscillations in different frequency bands have been shown to be intimately involved in exploration of environment and cognition. Here, the local field potentials in the hippocampus, the medial prefrontal cortex (mPFC), and the medial entorhinal cortex (mEC) were recorded simultaneously in rats during the execution of the episodic-like memory task. The power of hippocampal theta (~4-10 Hz), slow gamma (~25-50 Hz), and fast gamma oscillations (~55-100 Hz) was analyzed in all structures examined. Particular attention was paid to the theta coherence between three mentioned structures. The modulation of the power of gamma rhythms by the phase of theta cycle during the execution of the episodic-like memory test by rats was also closely studied. Healthy rats and rats one month after kainate-induced status epilepticus (SE) were examined. Paroxysmal activity in the hippocampus (high amplitude interictal spikes), excessive excitability of animals, and the death of hippocampal and dentate granular cells in rats with kainate-evoked SE were observed, which indicated the development of seizure focus in the hippocampus (epileptogenesis). One month after SE, the rats exhibited a specific impairment of episodic memory for the what-where-when triad: unlike healthy rats, epileptogenic SE animals did not identify the objects during the test. This impairment was associated with the changes in the characteristics of theta and gamma rhythms and specific violation of theta coherence and theta/gamma coupling in these structures in comparison with the healthy animals. We believe that these disturbances in the cortical areas play a role in episodic memory dysfunction in kainate-treated animals. These findings can shed light on the mechanisms of cognitive deficit during epileptogenesis.

A REVIEW OF PROTOCOLS AND GUIDELINES ADDRESSING THE EXPOSURE OF OCCUPANTS TO ELECTROMAGNETIC FIELD RADIATION (EMFR) IN BUILDINGS

2021 ◽  
Vol 16 (2) ◽  
pp. 55-81
Author(s):  
Shabnam Monadizadeh ◽  
Charles J. Kibert ◽  
Jiaxuan Li ◽  
Junghoon Woo ◽  
Ashish Asutosh ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Human Health ◽  
Health Effects ◽  
Action Plan ◽  
Low Frequency ◽  
Cellular Level ◽  
Future Research ◽  
Ir Radiation ◽  
Health Authorities ◽  
Field Radiation

HIGHLIGHTS ABSTRACT A significant share of the technology that has emerged over the past several decades produces electromagnetic field (EMFR) radiation. Communications devices, household appliances, industrial equipment, and medical equipment and devices all produce EMFR with a variety of frequencies, strengths, and ranges. Some EMFR, such as Extremely Low Frequency (ELF), Radio Frequency (RF), and Ionizing Range (IR) radiation have been shown to have harmful effects on human health. Depending on the frequency and strength of the radiation, EMFR can have health effects at the cellular level as well as at brain, nervous, and cardiovascular levels. Health authorities have enacted regulations locally and globally to set critical values to limit the adverse effects of EMFR. By introducing a more comprehensive field of EMFR study and practice, architects and designers can design for a safer electromagnetic (EM) indoor environment, and, as building and construction specialists, will be able to monitor and reduce EM radiation. This paper identifies the nature of EMFR in the built environment, the various EMFR sources, and its human health effects. It addresses European and US regulations for EMFR in buildings and provides a preliminary action plan. The challenges of developing measurement protocols for the various EMFR frequency ranges and determining the effects of EMFR on building occupants are discussed. This paper argues that a mature method for measuring EMFR in building environments and linking these measurements to human health impacts will foster occupant health and lead to the adequate development of safeguards for occupants of buildings in future research.

Person Memory Mechanism Underlying Approach and Avoidance Judgments of Social Targets

2021 ◽  
Vol 39 (6) ◽  
pp. 747-772
Author(s):  
Allison M. Sklenar ◽  
Matthew P. McCurdy ◽  
Andrea N. Frankenstein ◽  
Matt Motyl ◽  
Eric D. Leshikar
Keyword(s):  
Episodic Memory ◽  
Political Ideology ◽  
Negative Information ◽  
Cognitive Factors ◽  
Future Research ◽  
Social Judgments ◽  
Approach And Avoidance ◽  
Memory Mechanism ◽  
Person Memory ◽  
Approach Avoidance

People display approach and avoidance tendencies toward social targets. Although much research has studied the factors that affect decisions to approach or avoid targets, less work has investigated whether cognitive factors, such as episodic memory (e.g., details remembered about others from previous encounters) contribute to such judgments. Across two experiments, participants formed positive or negative impressions of targets based on their picture, a trait-implying behavior (Experiments 1 & 2), and their political ideology (conservative or liberal; Experiment 2). Memory and approach/avoidance decisions for targets were then measured. Results showed remembering negative impressions about targets increased avoidance responses, whereas remembering positive impressions increased approach responses. Strikingly, falsely remembering negative impressions for novel social targets (not seen before) also induced avoidance. Results suggest remembering negative information about targets, whether correctly or falsely, strongly influences future social judgments. Overall, these data support an episodic memory mechanism underlying subsequent approach/avoidance judgments, which is a rich area for future research.

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