scholarly journals Spatiotemporal patterns of neocortical activity around hippocampal sharp-wave ripples

2019 ◽  
Author(s):  
J. Karimi Abadchi ◽  
M. Nazari-Ahangarkolaee ◽  
S. Gattas ◽  
E. Bermudez-Contreras ◽  
A. Luczak ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Retrosplenial Cortex ◽  
Spatiotemporal Patterns ◽  
Extracellular Glutamate ◽  
Sharp Wave ◽  
Recent Memory ◽  
Memory Traces ◽  
Multiunit Activity ◽  
Trigger Event

AbstractA prevalent model is that sharp-wave ripples (SWR) arise ‘spontaneously’ in CA3 and propagate recent memory traces outward to the neocortex to facilitate memory consolidation there. Using voltage and extracellular glutamate transient recording over widespread regions of mice dorsal neocortex in relation to CA1 multiunit activity (MUA) and SWR, we find that the largest SWR-related modulation occurs in retrosplenial cortex; however, contrary to the unidirectional hypothesis, neocortical activation exhibited a continuum of activation timings relative to SWRs, varying from leading to lagging. Thus, contrary to the model in which SWRs arise ‘spontaneously’ in the hippocampus, neocortical activation often precedes SWRs and may thus constitute a trigger event in which neocortical information seeds associative reactivation of hippocampal ‘indices’. This timing continuum is consistent with a dynamics in which older, more consolidated memories may in fact initiate the hippocampal-neocortical dialog, whereas reactivation of newer memories may be initiated predominantly in the hippocampus.

scholarly journals Spatiotemporal patterns of neocortical activity around hippocampal sharp-wave ripples

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
J Karimi Abadchi ◽  
Mojtaba Nazari-Ahangarkolaee ◽  
Sandra Gattas ◽  
Edgar Bermudez-Contreras ◽  
Artur Luczak ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Retrosplenial Cortex ◽  
Spatiotemporal Patterns ◽  
Extracellular Glutamate ◽  
Sharp Wave ◽  
Recent Memory ◽  
Memory Traces ◽  
Multiunit Activity ◽  
Trigger Event

A prevalent model is that sharp-wave ripples (SWR) arise ‘spontaneously’ in CA3 and propagate recent memory traces outward to the neocortex to facilitate memory consolidation there. Using voltage and extracellular glutamate transient recording over widespread regions of mice dorsal neocortex in relation to CA1 multiunit activity (MUA) and SWR, we find that the largest SWR-related modulation occurs in retrosplenial cortex; however, contrary to the unidirectional hypothesis, neocortical activation exhibited a continuum of activation timings relative to SWRs, varying from leading to lagging. Thus, contrary to the model in which SWRs arise ‘spontaneously’ in the hippocampus, neocortical activation often precedes SWRs and may thus constitute a trigger event in which neocortical information seeds associative reactivation of hippocampal ‘indices’. This timing continuum is consistent with a dynamics in which older, more consolidated memories may in fact initiate the hippocampal-neocortical dialog, whereas reactivation of newer memories may be initiated predominantly in the hippocampus.

scholarly journals Hippocampus-retrosplenial cortex interaction is increased during phasic REM and contributes to memory consolidation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel Gomes de Almeida-Filho ◽  
Bruna Del Vechio Koike ◽  
Francesca Billwiller ◽  
Kelly Soares Farias ◽  
Igor Rafael Praxedes de Sales ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Memory Consolidation ◽  
Retrosplenial Cortex ◽  
Contextual Fear Conditioning ◽  
Oscillatory Activity ◽  
Theta Oscillation ◽  
Contextual Fear ◽  
Before And After ◽  
Freely Behaving ◽  
Phasic Rem Sleep

AbstractHippocampal (HPC) theta oscillation during post-training rapid eye movement (REM) sleep supports spatial learning. Theta also modulates neuronal and oscillatory activity in the retrosplenial cortex (RSC) during REM sleep. To investigate the relevance of theta-driven interaction between these two regions to memory consolidation, we computed the Granger causality within theta range on electrophysiological data recorded in freely behaving rats during REM sleep, both before and after contextual fear conditioning. We found a training-induced modulation of causality between HPC and RSC that was correlated with memory retrieval 24 h later. Retrieval was proportional to the change in the relative influence RSC exerted upon HPC theta oscillation. Importantly, causality peaked during theta acceleration, in synchrony with phasic REM sleep. Altogether, these results support a role for phasic REM sleep in hippocampo-cortical memory consolidation and suggest that causality modulation between RSC and HPC during REM sleep plays a functional role in that phenomenon.

Chlorpromazine and Memory Consolidation

1965 ◽  
Vol 17 (3) ◽  
pp. 705-706 ◽  
Author(s):  
Henry E. Adams ◽  
L. J. Peacock ◽  
John F. Glenn
Keyword(s):  
Factorial Design ◽  
Memory Consolidation ◽  
Water Deprivation ◽  
Straight Alley ◽  
Learning Trial ◽  
Water Reward ◽  
Simple Task ◽  
Memory Traces ◽  
Main Effects

To determine whether chlorpromazine affects learning by disrupting memory traces 40 23-hr. water-deprived rats were given 1 trial per day in a straight alley maze for a water reward. The factorial design included (a) chlorpromazine vs saline and (b) injection 10 sec. after a learning trial vs injection 30 min. after a learning trial. All groups learned but there were no significant main effects or interaction, which indicates that chlorpromazine does not affect learning this simple task under water-deprivation.

scholarly journals Bidirectional Interaction of Hippocampal Ripples and Cortical Slow Waves Leads to Coordinated Spiking Activity During NREM Sleep

2020 ◽  
Vol 31 (1) ◽  
pp. 324-340
Author(s):  
Pavel Sanda ◽  
Paola Malerba ◽  
Xi Jiang ◽  
Giri P Krishnan ◽  
Jorge Gonzalez-Martinez ◽  
...  
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Nrem Sleep ◽  
Slow Waves ◽  
Slow Oscillation ◽  
Cortical Input ◽  
Sharp Wave ◽  
Up States ◽  
Intracranial Recordings

Abstract The dialogue between cortex and hippocampus is known to be crucial for sleep-dependent memory consolidation. During slow wave sleep, memory replay depends on slow oscillation (SO) and spindles in the (neo)cortex and sharp wave-ripples (SWRs) in the hippocampus. The mechanisms underlying interaction of these rhythms are poorly understood. We examined the interaction between cortical SO and hippocampal SWRs in a model of the hippocampo–cortico–thalamic network and compared the results with human intracranial recordings during sleep. We observed that ripple occurrence peaked following the onset of an Up-state of SO and that cortical input to hippocampus was crucial to maintain this relationship. A small fraction of ripples occurred during the Down-state and controlled initiation of the next Up-state. We observed that the effect of ripple depends on its precise timing, which supports the idea that ripples occurring at different phases of SO might serve different functions, particularly in the context of encoding the new and reactivation of the old memories during memory consolidation. The study revealed complex bidirectional interaction of SWRs and SO in which early hippocampal ripples influence transitions to Up-state, while cortical Up-states control occurrence of the later ripples, which in turn influence transition to Down-state.

scholarly journals 0084 Sleep Consolidates Incidentally Encoded Information After Deep but Not Shallow Encoding

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A34-A34
Author(s):  
E M Wernette ◽  
K M Fenn
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Declarative Memory ◽  
Memory Performance ◽  
Memory Test ◽  
Memory Traces ◽  
Incidental Encoding ◽  
The Relationship ◽  
With Memory

Abstract Introduction Slow wave sleep (SWS) strengthens declarative memory for information studied for a later test. However, research on the effect of sleep on information that is not intentionally remembered is scare. Previous research from our lab suggests sleep consolidates some, but not all, information that has been encoded incidentally, meaning that it has been acted on but not intentionally remembered. It remains unclear what determines which information benefits from sleep-dependent consolidation processes and what aspects of sleep are related to these mnemonic benefits. In two experiments, we test the hypothesis that sleep consolidates strong but not weak memory traces following incidental encoding, and assess the relationship between memory performance and objective sleep characteristics. Methods In Experiment 1, participants rated words one (weak traces) or three times (strong traces) in a deep or shallow incidental encoding task. Participants either rated words on a scale from ‘concrete’ to ‘abstract’ (deep) or counted the vowels in the words (shallow). Following a 12-hour period containing sleep or wakefulness, participants took a surprise memory test. In Experiment 2, participants rated words one or three times in the deep encoding task, received an 8-hour sleep opportunity with polysomnography, and took the surprise memory test. Results In Experiment 1, participants remembered words better after sleep than wake regardless of whether words were encoded one or three times, but only after deep encoding. Sleep did not consolidate information following shallow encoding. Experiment 2 is ongoing, but we predict that the amount of SWS will correlate positively with memory. Conclusion Results thus far suggest sleep may have consolidated information based on the strength of memory traces. Because deep encoding results in stronger memory traces than shallow encoding, this work is broadly consistent with theories of memory consolidation that predict sleep is more beneficial for strong memory traces than weak, such as the synaptic downscaling hypothesis. Support N/A

scholarly journals Does Sleep Promote False Memories?

2011 ◽  
Vol 23 (1) ◽  
pp. 26-40 ◽  
Author(s):  
Annabelle Darsaud ◽  
Hedwige Dehon ◽  
Olaf Lahl ◽  
Virginie Sterpenich ◽  
Mélanie Boly ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Memory Consolidation ◽  
Declarative Memory ◽  
False Memories ◽  
Retrosplenial Cortex ◽  
New Words ◽  
Brain Responses ◽  
Fmri Session ◽  
Significant Difference ◽  
Lack Of Sleep

Memory is constructive in nature so that it may sometimes lead to the retrieval of distorted or illusory information. Sleep facilitates accurate declarative memory consolidation but might also promote such memory distortions. We examined the influence of sleep and lack of sleep on the cerebral correlates of accurate and false recollections using fMRI. After encoding lists of semantically related word associates, half of the participants were allowed to sleep, whereas the others were totally sleep deprived on the first postencoding night. During a subsequent retest fMRI session taking place 3 days later, participants made recognition memory judgments about the previously studied associates, critical theme words (which had not been previously presented during encoding), and new words unrelated to the studied items. Sleep, relative to sleep deprivation, enhanced accurate and false recollections. No significant difference was observed in brain responses to false or illusory recollection between sleep and sleep deprivation conditions. However, after sleep but not after sleep deprivation (exclusive masking), accurate and illusory recollections were both associated with responses in the hippocampus and retrosplenial cortex. The data suggest that sleep does not selectively enhance illusory memories but rather tends to promote systems-level consolidation in hippocampo-neocortical circuits of memories subsequently associated with both accurate and illusory recollections. We further observed that during encoding, hippocampal responses were selectively larger for items subsequently accurately retrieved than for material leading to illusory memories. The data indicate that the early organization of memory during encoding is a major factor influencing subsequent production of accurate or false memories.

scholarly journals Unexpected changes in learned task contingencies trigger sharp wave ripples in the primate hippocampus during virtual navigation

2020 ◽  
Author(s):  
Mary McIntosh ◽  
Benjamin Corrigan ◽  
Roberto Gulli ◽  
Guillaume Doucet ◽  
Julio Martinez-Trujillo ◽  
...  
Keyword(s):  
Associative Learning ◽  
Memory Consolidation ◽  
Event Related Potentials ◽  
Field Potentials ◽  
Virtual Navigation ◽  
Temporal Lobes ◽  
Sharp Wave ◽  
Learning Tasks ◽  
Related Potentials ◽  
3D Virtual Environment

Abstract The hippocampi and mesial temporal lobes play a central role in episodic memory and associative learning. It is unclear how unexpected experience influences learning. Hippocampal sharp wave ripples (SWR) are an electrical biomarker of memory consolidation. We tracked when and where SWR occur during 2 tasks. Local field potentials were recorded in the hippocampi, entorhinal cortices and amygdalae of non-human primates (NHP; n=3) performing reversal and associative learning tasks in a 3D virtual environment. Our results show hippocampal SWR occurred when learned task contingencies were unexpectedly altered. Surprise rewards and reward denial were associated with SWR rates 9.8x and 8.0x greater than expected rewards. The highest density of SWR occurred in zones where errors were made. SWR were preceded by event-related potentials in the amygdala but not entorhinal cortex. Our results suggest that SWR generation in primates may prioritize behaviourally relevant experience for commitment to memory to allow flexible learning.

Off-Line Reprocessing of Recent Memory and its Role in Memory Consolidation: A Progress Report

2003 ◽  
pp. 225-246 ◽  
Author(s):  
B. L. McNaughton ◽  
C. A. Barnes ◽  
F. P. Battaglia ◽  
M. R. Bower ◽  
S. L. Cowen ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Progress Report ◽  
Recent Memory

scholarly journals Author response: Spatiotemporal patterns of neocortical activity around hippocampal sharp-wave ripples

2020 ◽  
Author(s):  
J Karimi Abadchi ◽  
Mojtaba Nazari-Ahangarkolaee ◽  
Sandra Gattas ◽  
Edgar Bermudez-Contreras ◽  
Artur Luczak ◽  
...  
Keyword(s):  
Spatiotemporal Patterns ◽  
Author Response ◽  
Sharp Wave
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