scholarly journals Parvalbumin-expressing interneurons coordinate hippocampal network dynamics required for memory consolidation

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Nicolette Ognjanovski ◽  
Samantha Schaeffer ◽  
Jiaxing Wu ◽  
Sima Mofakham ◽  
Daniel Maruyama ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Activity Patterns ◽  
Memory Formation ◽  
Contextual Fear Conditioning ◽  
Long Term Memory ◽  
Ca1 Neurons ◽  
Functional Connections ◽  
The Hours ◽  
Hippocampal Area ◽  
Episodic Memories

Abstract Activity in hippocampal area CA1 is essential for consolidating episodic memories, but it is unclear how CA1 activity patterns drive memory formation. We find that in the hours following single-trial contextual fear conditioning (CFC), fast-spiking interneurons (which typically express parvalbumin (PV)) show greater firing coherence with CA1 network oscillations. Post-CFC inhibition of PV+ interneurons blocks fear memory consolidation. This effect is associated with loss of two network changes associated with normal consolidation: (1) augmented sleep-associated delta (0.5–4 Hz), theta (4–12 Hz) and ripple (150–250 Hz) oscillations; and (2) stabilization of CA1 neurons’ functional connectivity patterns. Rhythmic activation of PV+ interneurons increases CA1 network coherence and leads to a sustained increase in the strength and stability of functional connections between neurons. Our results suggest that immediately following learning, PV+ interneurons drive CA1 oscillations and reactivation of CA1 ensembles, which directly promotes network plasticity and long-term memory formation.

scholarly journals The Role and Mechanisms of Action of Glucocorticoid Involvement in Memory Storage

1998 ◽  
Vol 6 (3) ◽  
pp. 41-52 ◽  
Author(s):  
Carmen Sandi
Keyword(s):  
Glucocorticoid Receptors ◽  
Molecular Mechanisms ◽  
Memory Formation ◽  
Contextual Fear Conditioning ◽  
Memory Storage ◽  
Long Term Memory ◽  
Contextual Fear ◽  
Adrenal Steroid ◽  
Response To Stress ◽  
Mechanisms Of Memory

Adrenal steroid hormones modulate learning and memory processes by interacting with specific glucocorticoid receptors at different brain areas. In this article, certain components of the physiological response to stress elicited by learning situations are proposed to form an integral aspect of the neurobiological mechanism underlying memory formation. By reviewing the work carried out in different learning models in chicks (passive avoidance learning) and rats (spatial orientation in the Morris water maze and contextual fear conditioning), a role for brain corticosterone action through the glucocorticoid receptor type on the mechanisms of memory consolidation is hypothesized. Evidence is also presented to relate post-training corticosterone levels to the strength of memory storage. Finally, the possible molecular mechanisms that might mediate the influences of glucocorticoids in synaptic plasticity subserving long-term memory formation are considered, mainly by focusing on studies implicating a steroid action through (i) glutamatergic transmission and (ii) cell adhesion molecules.

scholarly journals 0119 The Role of Aging and Working Memory in Emotional-Long Term Memory Formation

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A47-A47
Author(s):  
N Sattari ◽  
L Whitehurst ◽  
K Vinces ◽  
S Mednick
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Memory Consolidation ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Improvement ◽  
Condition Interaction

Abstract Introduction It is widely accepted that “offline” processes during sleep contributes to memory. Working Memory (WM) capacity, which reflects “online” memory processing, is an important factor influencing cognitive functioning, which declines with age. In younger individuals, a positive association is reported between WM-capacity and declarative memory improvement. Methods We examined the relation between WM and long-term memory consolidation, among younger [N=105, 18-25yr] and older adults (N=119, 60-85yr). Subjects completed an OSPAN WM task, encoded a Word-Paired Association (WPA) task in the morning (Test1), and were tested on the WPA in the afternoon (Test2) after a 90-minute polysomnographically-recorded nap or wake. Half of the subjects were exposed to negatively valenced word-pairs (EWPA) while the other half were exposed to neutral word-pairs (NWPA). Subjects rated valence of the word-pairs at Test1 and Test2. We compared the four groups (young-EWPA, young-NWPA, old-EWPA and old-NWPA) on WM and WPA in both wake and sleep. Results In both wake and sleep, in the WPA, ageXword-condition interaction was found (p=.004). Post-hoc analysis revealed that in wake, younger-EWPA had higher performance (p=.03) than younger-NWPA, however, older-EWPA had lower performance (p=.03) than older-NWPA. Additionally, we found an ageXword-condition interaction whereby youngers showed no change in ratings, while older adults rated word-pairs more positively both in wake (p=.03) and sleep (p=.002) at Test 2. Youngers had higher WM performance (p=.007), also their WM performance was positively associated with WPA both for Neutral (p=.03) and Emotional (p=.01). WM and WPA among older adults was not related. In younger-EWPA, Stage2-sleep-minutes was positively associated to WPA improvement (p=.03) where this association was negative among older-EWPA (p=.02). In older-NWPA, Stage2-sleep-minutes was positively associated with WPA (p=.004). Conclusion Our findings indicate an association between WM and emotionally-salient memory formation that is modulated by age. Older adults, but not younger, showed the emotional bias previously reported. WM was higher in younger adults related to memory improvement. Stage2-sleep was related to memory improvement in both groups, but in opposite directions. In sum, the role of sleep in memory consolidation changes with aging and WM may play a role in this process. Support Fenn et al.,2012

scholarly journals Metabolomic profiling reveals a differential role for hippocampal glutathione reductase in infantile memory formation

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Benjamin Bessières ◽  
Emmanuel Cruz ◽  
Cristina M Alberini
Keyword(s):  
Glutathione Reductase ◽  
Reduced Glutathione ◽  
Memory Formation ◽  
Long Term Memory ◽  
Adult Rats ◽  
Metabolomic Profiling ◽  
Behavioral Assessments ◽  
Cellular Defenses ◽  
Episodic Memories

The metabolic mechanisms underlying the formation of early-life episodic memories remain poorly characterized. Here, we assessed the metabolomic profile of the rat hippocampus at different developmental ages both at baseline and following episodic learning. We report that the hippocampal metabolome significantly changes over developmental ages and that learning regulates differential arrays of metabolites according to age. The infant hippocampus had the largest number of significant changes following learning, with downregulation of 54 metabolites. Of those, a large proportion was associated with the glutathione-mediated cellular defenses against oxidative stress. Further biochemical, molecular, and behavioral assessments revealed that infantile learning evokes a rapid and persistent increase in the activity of neuronal glutathione reductase, the enzyme that regenerates reduced glutathione from its oxidized form. Inhibition of glutathione reductase selectively impaired long-term memory formation in infant but not in juvenile and adult rats, confirming its age-specific role. Thus, metabolomic profiling revealed that the hippocampal glutathione-mediated antioxidant pathway is differentially required for the formation of infantile memory.

Short-term memory formation and long-term memory consolidation are enhanced by cellular prion association to stress-inducible protein 1

2007 ◽  
Vol 26 (1) ◽  
pp. 282-290 ◽  
Author(s):  
Adriana S. Coitinho ◽  
Marilene H. Lopes ◽  
Glaucia N.M. Hajj ◽  
Janine I. Rossato ◽  
Adriana R. Freitas ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Short Term Memory ◽  
Memory Formation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Inducible Protein

scholarly journals New Insights on Retrieval-Induced and Ongoing Memory Consolidation: Lessons from Arc

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Jean-Pascal Morin ◽  
Kioko Guzmán-Ramos ◽  
Federico Bermudez-Rattoni
Keyword(s):  
Memory Consolidation ◽  
Memory Formation ◽  
Mammalian Brain ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Traces ◽  
Initial Acquisition ◽  
Molecular Events ◽  
Trace Model

The mainstream view on the neurobiological mechanisms underlying memory formation states that memory traces reside on the network of cells activated during initial acquisition that becomes active again upon retrieval (reactivation). These activation and reactivation processes have been called “conjunctive trace.” This process implies that singular molecular events must occur during acquisition, strengthening the connection between the implicated cells whose synchronous activity must underlie subsequent reactivations. The strongest experimental support for the conjunctive trace model comes from the study of immediate early genes such as c-fos, zif268, and activity-regulated cytoskeletal-associated protein. The expressions of these genes are reliably induced by behaviorally relevant neuronal activity and their products often play a central role in long-term memory formation. In this review, we propose that the peculiar characteristics of Arc protein, such as its optimal expression after ongoing experience or familiar behavior, together with its versatile and central functions in synaptic plasticity could explain how familiarization and recognition memories are stored and preserved in the mammalian brain.

scholarly journals The relation of transcription to memory formation.

2003 ◽  
Vol 50 (3) ◽  
pp. 775-782 ◽  
Author(s):  
Edward Korzus
Keyword(s):  
Transcription Factor ◽  
Memory Consolidation ◽  
Memory Formation ◽  
Information Storage ◽  
Long Term Memory ◽  
Behavioral Studies ◽  
Activation Of Transcription ◽  
Element Binding Protein ◽  
Downstream Processes

A distinction between short-term memories lasting minutes to hours and long-term memories lasting for many days is that the formation of long-term memories requires new gene expression. In this review, the focus is on the current understanding of the relation of transcription to memory consolidation based on the data collected from behavioral studies performed primarily on genetically altered animals. Studies in Drosophila and Aplysia indicate that the transcription factor cAMP/Ca(2+) response element binding protein (CREB) is critical in mediating the conversion from short- to long-term memory. More recent genetic studies in mice also demonstrated CREB and inducible transcription factor Zif268 involvement in information storage processes. Transcription seems to play essential role in memory formation but the mechanisms for activation of transcription and downstream processes during memory consolidation remain unclear.

scholarly journals Effects of intrahippocampal administration of the phosphatase inhibitor okadaic acid: Dual effects on memory formation

2010 ◽  
Vol 4 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Monica R.M. Vianna ◽  
Adriana Coitinho ◽  
Luciana Izquierdo ◽  
Ivan Izquierdo
Keyword(s):  
Okadaic Acid ◽  
Memory Consolidation ◽  
Potent Inhibitor ◽  
Inhibitory Avoidance ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory ◽  
Step Down

Abstract Protein phosphorylation mediated by serine-threonine kinases in the hippocampus is crucial to the synaptic modifications believed to underlie memory formation. The role of phosphatases has been the focus of comparatively little study. Objectives: Here we evaluate the contribution of the serine-threonine protein phosphatases 1 and 2A (PP1, PP2A) on memory consolidation. Methods: We used immediate post-training bilateral hippocampal infusions of okadaic acid (OA, 0.01 and 10 pmol/side), a potent inhibitor of PP1 and PP2A, and measured short- [3 h] and long-term memory [24 h] (STM, LTM) of step-down inhibitory avoidance. Results: At the lower dose, OA inhibited both STM and LTM whereas at the higher dose it instead enhanced LTM. Pre-test infusion of these two doses of OA had no effect on retrieval. Conclusions: These two doses of OA are known to selectively inhibit PP1 and PP2A respectively. These findings point to the importance of these enzymes in memory formation and also suggest a deleterious influence of endogenous hippocampal PP2A on LTM formation.

scholarly journals Ripples Make Waves: Binding Structured Activity and Plasticity in Hippocampal Networks

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Josef H. L. P. Sadowski ◽  
Matthew W. Jones ◽  
Jack R. Mellor
Keyword(s):  
Neural Network ◽  
Activity Patterns ◽  
Sensory Information ◽  
Memory Formation ◽  
Spatial Representations ◽  
Multistage Process ◽  
Recent Activity ◽  
Episodic Memories ◽  
Network States ◽  
Hippocampal Networks

Establishing novel episodic memories and stable spatial representations depends on an exquisitely choreographed, multistage process involving the online encoding and offline consolidation of sensory information, a process that is largely dependent on the hippocampus. Each step is influenced by distinct neural network states that influence the pattern of activation across cellular assemblies. In recent years, the occurrence of hippocampal sharp wave ripple (SWR) oscillations has emerged as a potentially vital network phenomenon mediating the steps between encoding and consolidation, both at a cellular and network level by promoting the rapid replay and reactivation of recent activity patterns. Such events facilitate memory formation by optimising the conditions for synaptic plasticity to occur between contingent neural elements. In this paper, we explore the ways in which SWRs and other network events can bridge the gap between spatiomnemonic processing at cellular/synaptic and network levels in the hippocampus.

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