scholarly journals Fast and slow cortical high frequency oscillations for cortico-cortical and cortico-hippocampal network consolidation during NonREM sleep

2019 ◽  
Author(s):  
Adrian Aleman-Zapata ◽  
Richard GM Morris ◽  
Lisa Genzel
Keyword(s):  
Memory Consolidation ◽  
High Frequency ◽  
Long Term Memory ◽  
Causality Analysis ◽  
Granger Causality Analysis ◽  
High Frequency Oscillations ◽  
New Information ◽  
Hippocampal Network ◽  
Nonrem Sleep

AbstractMemory reactivation during NonREM-ripples is thought to communicate new information to a systems-wide network. Cortical high frequency events have also been described that co-occur with ripples. Focusing on NonREM sleep after different behaviors, both hippocampal ripples and parietal high frequency oscillations were detected. A bimodal frequency distribution was observed in the parietal high frequency events, faster and slower, with increases in prefrontal directionality measured by Granger causality analysis specifically seen during the fast parietal oscillations. Furthermore, fast events activated prefrontal-parietal cortex whereas slow events activated hippocampal-parietal areas. Finally, there was a learning-induced increase in both number and size of fast high frequency events. These patterns were not seen after novelty exposure or foraging, but occurred after the learning of a new goal location in a maze. Disruption of either sleep or hippocampal ripples impaired long-term memory consistent with these having a role in memory consolidation.

scholarly journals Frequency Effects on Memory: A Resource-Limited Theory

2018 ◽  
Author(s):  
Vencislav Popov ◽  
Lynne Reder
Keyword(s):  
High Frequency ◽  
Inverse Function ◽  
Long Term Memory ◽  
Study Item ◽  
Frequency Effects ◽  
Storage And Retrieval ◽  
Resource Limited ◽  
New Information ◽  
Familiar Stimuli

We present a review of frequency effects in memory, accompanied by a theory of memory, according to which the storage of new information in long-term memory (LTM) depletes a limited pool of working memory (WM) resources as an inverse function of item strength. We support the theory by showing that items with stronger representations in LTM (e.g. high frequency items) are easier to store, bind to context, and bind to one another; that WM resources are involved in storage and retrieval from LTM; that WM performance is better for stronger, more familiar stimuli. We present a novel analysis of preceding item strength, in which we show from nine existing studies that memory for an item is higher if during study it was preceded by a stronger item (e.g. a high frequency word). This effect is cumulative (the more prior items are of high frequency, the better), continuous (memory proportional to word frequency of preceding item), interacts with current item strength (larger for weaker items) and interacts with lag (decreases as the lag between the current and prior study item increases). A computational model that implements the theory is presented, which accounts for these effects. We discuss related phenomena that the model/theory can explain.

scholarly journals Rehearsal initiates systems memory consolidation, sleep makes it last

2019 ◽  
Vol 5 (4) ◽  
pp. eaav1695 ◽  
Author(s):  
L. Himmer ◽  
M. Schönauer ◽  
D. P. J. Heib ◽  
M. Schabus ◽  
S. Gais
Keyword(s):  
Memory Consolidation ◽  
Posterior Parietal Cortex ◽  
Memory Systems ◽  
Long Term Memory ◽  
Systems Consolidation ◽  
New Information ◽  
Study Session ◽  
Posterior Parietal

After encoding, memories undergo a transitional process termed systems memory consolidation. It allows fast acquisition of new information by the hippocampus, as well as stable storage in neocortical long-term networks, where memory is protected from interference. Whereas this process is generally thought to occur slowly over time and sleep, we recently found a rapid memory systems transition from hippocampus to posterior parietal cortex (PPC) that occurs over repeated rehearsal within one study session. Here, we use fMRI to demonstrate that this transition is stabilized over sleep, whereas wakefulness leads to a reset to naïve responses, such as observed during early encoding. The role of sleep therefore seems to go beyond providing additional rehearsal through memory trace reactivation, as previously thought. We conclude that repeated study induces systems consolidation, while sleep ensures that these transformations become stable and long lasting. Thus, sleep and repeated rehearsal jointly contribute to long-term memory consolidation.

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 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.

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

scholarly journals Transient relay function of midline thalamic nuclei during long-term memory consolidation in humans

2015 ◽  
Vol 22 (10) ◽  
pp. 527-531 ◽  
Author(s):  
Jan-Willem Thielen ◽  
Atsuko Takashima ◽  
Femke Rutters ◽  
Indira Tendolkar ◽  
Guillén Fernández
Keyword(s):  
Memory Consolidation ◽  
Long Term Memory ◽  
Thalamic Nuclei ◽  
Term Memory

β1-and β2-adrenoceptors in hippocampal CA3 region are required for long-term memory consolidation in rats

2015 ◽  
Vol 1627 ◽  
pp. 109-118 ◽  
Author(s):  
Jian Zheng ◽  
Fei Luo ◽  
Nan-nan Guo ◽  
Zong-yue Cheng ◽  
Bao-ming Li
Keyword(s):  
Memory Consolidation ◽  
Long Term Memory ◽  
Term Memory ◽  
Hippocampal Ca3 ◽  
Ca3 Region
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