scholarly journals The Engram’s Dark Horse: How Interneurons Regulate State-Dependent Memory Processing and Plasticity

2021 ◽  
Vol 15 ◽  
Author(s):  
Frank Raven ◽  
Sara J. Aton
Keyword(s):  
Memory Consolidation ◽  
Temporal Dynamics ◽  
Cell Populations ◽  
Memory Encoding ◽  
Memory Processing ◽  
Therapeutic Implications ◽  
State Dependent ◽  
Brain States ◽  
Direct Regulation

Brain states such as arousal and sleep play critical roles in memory encoding, storage, and recall. Recent studies have highlighted the role of engram neurons–populations of neurons activated during learning–in subsequent memory consolidation and recall. These engram populations are generally assumed to be glutamatergic, and the vast majority of data regarding the function of engram neurons have focused on glutamatergic pyramidal or granule cell populations in either the hippocampus, amygdala, or neocortex. Recent data suggest that sleep and wake states differentially regulate the activity and temporal dynamics of engram neurons. Two potential mechanisms for this regulation are either via direct regulation of glutamatergic engram neuron excitability and firing, or via state-dependent effects on interneuron populations–which in turn modulate the activity of glutamatergic engram neurons. Here, we will discuss recent findings related to the roles of interneurons in state-regulated memory processes and synaptic plasticity, and the potential therapeutic implications of understanding these mechanisms.

scholarly journals Within and Between-person Correlates of the Temporal Dynamics of Resting EEG Microstates

2019 ◽  
Author(s):  
Anthony P. Zanesco ◽  
Brandon G. King ◽  
Alea C. Skwara ◽  
Clifford D. Saron
Keyword(s):  
Time Series ◽  
Individual Differences ◽  
Temporal Dynamics ◽  
Functional Organization ◽  
Occurrence Rate ◽  
Eyes Closed ◽  
State Dependent ◽  
Brain States ◽  
The Rich ◽  
And Gender

AbstractMicrostates reflect transient brain states resulting from the activity of synchronously active brain networks that predominate in the broadband EEG time series. Despite increasing interest in understanding how the functional organization of the brain varies across individuals, or the extent to which its spatiotemporal dynamics are state dependent, comparatively little research has examined within and between-person correlates of microstate temporal parameters in healthy populations. In the present study, neuroelectric activity recorded during eyes-closed rest and during simple visual fixation was segmented into a time series of transient microstate intervals. It was found that five data-driven microstate configurations explained the preponderance of topographic variance in the EEG time series of the 374 recordings (from 187 participants) included in the study. We observed that the temporal dynamics of microstates varied within individuals to a greater degree than they differed between persons, with within-person factors explaining a large portion of the variance in mean microstate duration and occurrence rate. Nevertheless, several individual differences were found to predict the temporal dynamics of microstates. Of these, age and gender were the most reliable. These findings suggest that not only do the rich temporal dynamics of whole-brain neuronal networks vary considerably within-individuals, but that microstates appear to differentiate persons based on trait individual differences. The current findings suggest that rather than focusing exclusively on between-person differences in microstates as measures of brain function, researchers should turn their attention towards understanding the factors contributing to within-person variation.

Evaluating the relationship between REM and memory consolidation: A need for scholarship and hypothesis testing

2000 ◽  
Vol 23 (6) ◽  
pp. 1007-1008 ◽  
Author(s):  
Carlyle Smith ◽  
Gregory M. Rose
Keyword(s):  
Hypothesis Testing ◽  
Memory Consolidation ◽  
Brain Activity ◽  
Memory Processing ◽  
Systematic Testing ◽  
Complete Synthesis ◽  
Testing Of Hypotheses ◽  
The Relationship ◽  
Rational Evaluation

The function of REM, or any other stage of sleep, can currently only be conjectured. A rational evaluation of the role of REM in memory processing requires systematic testing of hypotheses that are optimally derived from a complete synthesis of existing knowledge. Our view is that the large number of studies supporting a relationship between REM-related brain activity and memory is not easily explained away.[Vertes & Eastman]

Dreaming and Episodic Memory: A Functional Dissociation?

2003 ◽  
Vol 15 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Magdalena J. Fosse ◽  
Roar Fosse ◽  
J. Allan Hobson ◽  
Robert J. Stickgold
Keyword(s):  
Episodic Memory ◽  
Memory Consolidation ◽  
Life Experiences ◽  
Memory Systems ◽  
Memory Processing ◽  
Episodic Memories

The activity that takes place in memory systems during sleep is likely to be related to the role of sleep in memory consolidation and learning, as well as to the generation of dream hallucinations. This study addressed the often-stated hypothesis that replay of whole episodic memories contributes to the multimodal hallucinations of sleep. Over a period of 14 days, 29 subjects kept a log of daytime activities, events, and concerns, wrote down any recalled dreams, and scored the dreams for incorporation of any waking experiences. While 65% of a total of 299 sleep mentation reports were judged to reflect aspects of recent waking life experiences, the episodic replay of waking events was found in no more than 1–2% of the dream reports. This finding has implications for understanding the unique memory processing that takes place during the night and is consistent with evidence that sleep has no role in episodic memory consolidation.

The Hippocampus Promotes Effective Saccadic Information Gathering in Humans

2019 ◽  
Vol 31 (2) ◽  
pp. 186-201 ◽  
Author(s):  
Heather D. Lucas ◽  
Melissa C. Duff ◽  
Neal J. Cohen
Keyword(s):  
Eye Movements ◽  
Critical Role ◽  
Study Phase ◽  
Memory Encoding ◽  
Information Theoretic ◽  
Memory Processing ◽  
Subsequent Performance ◽  
Spatial Reconstruction ◽  
The Moment

It is well established that the hippocampus is critical for memory. Recent evidence suggests that one function of hippocampal memory processing is to optimize how people actively explore the world. Here we demonstrate that the link between the hippocampus and exploration extends even to the moment-to-moment use of eye movements during visuospatial memory encoding. In Experiment 1, we examined relationships between study-phase eye movements in healthy individuals and subsequent performance on a spatial reconstruction test. In addition to quantitative measures of viewing behaviors (e.g., how many fixations or saccades were deployed during study), we used the information–theoretic measure of entropy to assess the amount of randomness or disorganization in participants' scanning behaviors. We found that the use of scanpaths during study that were lower in entropy (e.g., more organized, less random) predicted more accurate spatial reconstruction both within and between participants. Scanpath entropy was a better predictor of reconstruction accuracy than were the quantitative measures of viewing. In Experiment 2, we found that individuals with hippocampal amnesia tended to engage in viewing patterns that were higher in entropy (less organized) relative to healthy comparisons. These findings reveal a critical role of the hippocampus in guiding eye movement exploration to optimize visuospatial relational memory.

scholarly journals Role of Attention in the Temporal Dynamics of Visual Working Memory Processing

2016 ◽  
Vol 16 (12) ◽  
pp. 1076
Author(s):  
Jane Jacob ◽  
Christianne Jacobs ◽  
Bruno Breitmeyer ◽  
Juha Silvanto
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Temporal Dynamics ◽  
Memory Processing

Role of melatonin in regulating neurogenesis: Implications for the neurodegenerative pathology and analogous therapeutics for Alzheimer’s disease

2020 ◽  
Vol 3 (2) ◽  
pp. 216-242 ◽  
Author(s):  
Mayuri Shukla ◽  
Areechun Sotthibundhu ◽  
Piyarat Govitrapong
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Adult Neurogenesis ◽  
Adult Brain ◽  
Therapeutic Approaches ◽  
Therapeutic Implications ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Progenitor Cell Proliferation

The revelation of adult brain exhibiting neurogenesis has established that the brain possesses great plasticity and that neurons could be spawned in the neurogenic zones where hippocampal adult neurogenesis attributes to learning and memory processes. With strong implications in brain functional homeostasis, aging and cognition, various aspects of adult neurogenesis reveal exuberant mechanistic associations thereby further aiding in facilitating the therapeutic approaches regarding the development of neurodegenerative processes in Alzheimer’s Disease (AD). Impaired neurogenesis has been significantly evident in AD with compromised hippocampal function and cognitive deficits. Melatonin the pineal indolamine augments neurogenesis and has been linked to AD development as its levels are compromised with disease progression. Here, in this review, we discuss and appraise the mechanisms via which melatonin regulates neurogenesis in pathophysiological conditions which would unravel the molecular basis in such conditions and its role in endogenous brain repair. Also, its components as key regulators of neural stem and progenitor cell proliferation and differentiation in the embryonic and adult brain would aid in accentuating the therapeutic implications of this indoleamine in line of prevention and treatment of AD.   

Sign in / Sign up

Export Citation Format

Share Document