scholarly journals Wilm’s tumor 1 promotes memory flexibility

2017 ◽  
Author(s):  
Chiara Mariottini ◽  
Leonardo Munari ◽  
Ellen Gunzel ◽  
Joseph M. Seco ◽  
Nikos Tzavaras ◽  
...  
Keyword(s):  
Long Term Potentiation ◽  
Long Term Memory ◽  
Memory Retention ◽  
Memory Strength ◽  
Post Traumatic Stress ◽  
Wilm's Tumor ◽  
Memory Flexibility ◽  
Wilm’S Tumor ◽  
Wilm’S Tumor 1

AbstractUnder physiological conditions, strength and persistence of memory must be regulated in order to produce behavioral flexibility. In fact, impairments in memory flexibility are associated with pathologies such as post-traumatic stress disorder or autism; however the underlying mechanisms that enable memory flexibility are still poorly understood. Here we identified the transcriptional repressor Wilm’s Tumor 1 (WT1) as a critical synaptic plasticity regulator that decreases memory strength, promoting memory flexibility. WT1 was activated in the hippocampus following induction of long-term potentiation (LTP) or learning. WT1 knockdown enhanced CA1 neuronal excitability, LTP and long-term memory whereas its over-expression weakened memory retention. Moreover, forebrain WT1-deficient mice showed deficits in both reversal, sequential learning tasks and contextual fear extinction, exhibiting impaired memory flexibility. We conclude that WT1 limits memory strength or promotes memory weakening, thus enabling memory flexibility, a process that is critical for learning from new experience.

scholarly journals Wilm’s tumor 1 promotes memory flexibility

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chiara Mariottini ◽  
Leonardo Munari ◽  
Ellen Gunzel ◽  
Joseph M. Seco ◽  
Nikos Tzavaras ◽  
...  
Keyword(s):  
Wilm's Tumor ◽  
Memory Flexibility ◽  
Wilm’S Tumor ◽  
Wilm’S Tumor 1

The role of PKMζ in the maintenance of long-term memory: a review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamish Patel ◽  
Reza Zamani
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Long Term Potentiation ◽  
Global Memory ◽  
Long Term Memory ◽  
Compensatory Mechanism ◽  
Term Memory ◽  
Kinase C

Abstract Long-term memories are thought to be stored in neurones and synapses that undergo physical changes, such as long-term potentiation (LTP), and these changes can be maintained for long periods of time. A candidate enzyme for the maintenance of LTP is protein kinase M zeta (PKMζ), a constitutively active protein kinase C isoform that is elevated during LTP and long-term memory maintenance. This paper reviews the evidence and controversies surrounding the role of PKMζ in the maintenance of long-term memory. PKMζ maintains synaptic potentiation by preventing AMPA receptor endocytosis and promoting stabilisation of dendritic spine growth. Inhibition of PKMζ, with zeta-inhibitory peptide (ZIP), can reverse LTP and impair established long-term memories. However, a deficit of memory retrieval cannot be ruled out. Furthermore, ZIP, and in high enough doses the control peptide scrambled ZIP, was recently shown to be neurotoxic, which may explain some of the effects of ZIP on memory impairment. PKMζ knockout mice show normal learning and memory. However, this is likely due to compensation by protein-kinase C iota/lambda (PKCι/λ), which is normally responsible for induction of LTP. It is not clear how, or if, this compensatory mechanism is activated under normal conditions. Future research should utilise inducible PKMζ knockdown in adult rodents to investigate whether PKMζ maintains memory in specific parts of the brain, or if it represents a global memory maintenance molecule. These insights may inform future therapeutic targets for disorders of memory loss.

The effects of continuous versus partial reinforcement schedules on associative learning, memory and extinction in Lymnaea stagnalis

2002 ◽  
Vol 205 (8) ◽  
pp. 1171-1178 ◽  
Author(s):  
Susan Sangha ◽  
Chloe McComb ◽  
Andi Scheibenstock ◽  
Christine Johannes ◽  
Ken Lukowiak
Keyword(s):  
Associative Learning ◽  
Operant Conditioning ◽  
Lymnaea Stagnalis ◽  
Partial Reinforcement ◽  
Long Term Memory ◽  
Memory Retention ◽  
Reinforcement Schedules ◽  
Conditioning Procedure ◽  
Term Memory

SUMMARY A continuous schedule of reinforcement (CR) in an operant conditioning procedure results in the acquisition of associative learning and the formation of long-term memory. A 50 % partial reinforcement (PR) schedule does not result in learning. The sequence of PR—CR training has different and significant effects on memory retention and resistance to extinction. A CR/PR schedule results in a longer-lasting memory than a PR/CR schedule. Moreover,the memory produced by the CR/PR schedule is resistant to extinction training. In contrast, extinction occurs following the PR/CR schedule.

scholarly journals Higher iridescent-to-pigment optical effect in flowers facilitates learning, memory and generalization in foraging bumblebees

2017 ◽  
Vol 284 (1865) ◽  
pp. 20171097 ◽  
Author(s):  
Géraud de Premorel ◽  
Martin Giurfa ◽  
Christine Andraud ◽  
Doris Gomez
Keyword(s):  
Bombus Terrestris ◽  
Optical Measurements ◽  
Long Term Memory ◽  
Memory Retention ◽  
Optical Effect ◽  
Plant Communication ◽  
Bona Fide ◽  
Angle Of View ◽  
Artificial Flowers

Iridescence—change of colour with changes in the angle of view or of illumination—is widespread in the living world, but its functions remain poorly understood. The presence of iridescence has been suggested in flowers where diffraction gratings generate iridescent colours. Such colours have been suggested to serve plant–pollinator communication. Here we tested whether a higher iridescence relative to corolla pigmentation would facilitate discrimination, learning and retention of iridescent visual targets. We conditioned bumblebees ( Bombus terrestris ) to discriminate iridescent from non-iridescent artificial flowers and we varied iridescence detectability by varying target iridescent relative to pigment optical effect. We show that bees rewarded on targets with higher iridescent relative to pigment effect required fewer choices to complete learning, showed faster generalization to novel targets exhibiting the same iridescence-to-pigment level and had better long-term memory retention. Along with optical measurements, behavioural results thus demonstrate that bees can learn iridescence-related cues as bona fide signals for flower reward. They also suggest that floral advertising may be shaped by competition between iridescence and corolla pigmentation, a fact that has important evolutionary implications for pollinators. Optical measurements narrow down the type of cues that bees may have used for learning. Beyond pollinator–plant communication, our experiments help understanding how receivers influence the evolution of iridescence signals generated by gratings.

Separate chemical inhibitors of long-term and short-term memory: contrasting effects of cycloheximide, ouabain and ethacrynic acid on various learning tasks in chickens

1977 ◽  
Vol 196 (1123) ◽  
pp. 171-195 ◽  
Keyword(s):  
Visual Discrimination ◽  
Short Term Memory ◽  
Ethacrynic Acid ◽  
Fixed Number ◽  
Long Term Memory ◽  
Training Procedure ◽  
Memory Retention ◽  
Short Term ◽  
Term Memory

Cycloheximide injected into the brains of chickens 10 min before training does not effect their learning of a visual discrimination task, or memory of that task for at least 1 h after training. When tested 24 h later no memory of the training procedure is detectable. In contrast, ouabain injected 10 min before training prevents the expression of learning during training. The block lasts for up to 1 h, but from that time on memory begins to appear. Ouabain does not affect performance when injected just before testing for memory retention 24 h after training. It therefore affects neither the readout of long-term memory nor motivation nor perceptual abilities necessary for performance of the learning task. In birds treated with ouabain, after training on an operant task for heat reward by a procedure requiring a fixed number of reinforcements, memory is absent 20 min later but is well established at 24 h. Cycloheximide blocks long-term memory of this task. Like ouabain, ethacrynic acid, injected into the brain of chickens 10 min before training prevents the expression of learning of visual discrimination. Ethacrynic acid hastens the decline of memory after one-trial passive avoidance learning. It also blocks observational learning. We conclude that ouabain and ethacrynic acid block access to short-term memory, whereas cycloheximide interferes with the registration of long-term memory. Comparing the pharmacology of ethacrynic acid and ouabain their common known actions are on the Na/K fluxes across cell membranes. We suggest that long lasting changes in distribution of these ions in recently active nerve cells may be at the basis of access to memory during and shortly after learning.

scholarly journals Meningeal γδ T cell–derived IL-17 controls synaptic plasticity and short-term memory

2019 ◽  
Vol 4 (40) ◽  
pp. eaay5199 ◽  
Author(s):  
Miguel Ribeiro ◽  
Helena C. Brigas ◽  
Mariana Temido-Ferreira ◽  
Paula A. Pousinha ◽  
Tommy Regen ◽  
...  
Keyword(s):  
T Cell ◽  
Short Term Memory ◽  
Long Term Potentiation ◽  
Long Term Memory ◽  
Interleukin 17 ◽  
Γδ T Cell ◽  
Short Term ◽  
Functional Link ◽  
Term Memory

The notion of “immune privilege” of the brain has been revised to accommodate its infiltration, at steady state, by immune cells that participate in normal neurophysiology. However, the immune mechanisms that regulate learning and memory remain poorly understood. Here, we show that noninflammatory interleukin-17 (IL-17) derived from a previously unknown fetal-derived meningeal-resident γδ T cell subset promotes cognition. When tested in classical spatial learning paradigms, mice lacking γδ T cells or IL-17 displayed deficient short-term memory while retaining long-term memory. The plasticity of glutamatergic synapses was reduced in the absence of IL-17, resulting in impaired long-term potentiation in the hippocampus. Conversely, IL-17 enhanced glial cell production of brain-derived neurotropic factor, whose exogenous provision rescued the synaptic and behavioral phenotypes of IL-17–deficient animals. Together, our work provides previously unknown clues on the mechanisms that regulate short-term versus long-term memory and on the evolutionary and functional link between the immune and nervous systems.

scholarly journals Neuro-Transistor Based on UV-Treated Charge Trapping in MoTe2 for Artificial Synaptic Features

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2326
Author(s):  
Shania Rehman ◽  
Muhammad Farooq Khan ◽  
Mehr Khalid Rahmani ◽  
Honggyun Kim ◽  
Harshada Patil ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Charge Trapping ◽  
Long Term Potentiation ◽  
Spike Timing ◽  
Long Term Memory ◽  
Ambient Conditions ◽  
Time Constants ◽  
Brain Functions ◽  
Gate Pulse

The diversity of brain functions depend on the release of neurotransmitters in chemical synapses. The back gated three terminal field effect transistors (FETs) are auspicious candidates for the emulation of biological functions to recognize the proficient neuromorphic computing systems. In order to encourage the hysteresis loops, we treated the bottom side of MoTe2 flake with deep ultraviolet light in ambient conditions. Here, we modulate the short-term and long-term memory effects due to the trapping and de-trapping of electron events in few layers of a MoTe2 transistor. However, MoTe2 FETs are investigated to reveal the time constants of electron trapping/de-trapping while applying the gate-voltage pulses. Our devices exploit the hysteresis effect in the transfer curves of MoTe2 FETs to explore the excitatory/inhibitory post-synaptic currents (EPSC/IPSC), long-term potentiation (LTP), long-term depression (LTD), spike timing/amplitude-dependent plasticity (STDP/SADP), and paired pulse facilitation (PPF). Further, the time constants for potentiation and depression is found to be 0.6 and 0.9 s, respectively which seems plausible for biological synapses. In addition, the change of synaptic weight in MoTe2 conductance is found to be 41% at negative gate pulse and 38% for positive gate pulse, respectively. Our findings can provide an essential role in the advancement of smart neuromorphic electronics.

Silymarin Prevents Memory Impairments, Anxiety, and Depressive-Like Symptoms in a Rat Model of Post-Traumatic Stress Disorder

Planta Medica ◽  
2018 ◽  
Vol 85 (01) ◽  
pp. 32-40 ◽  
Author(s):  
Tamam El-Elimat ◽  
Karem Alzoubi ◽  
Mahmoud AbuAlSamen ◽  
Zeinab Al Subeh ◽  
Tyler Graf ◽  
...  
Keyword(s):  
Post Traumatic Stress Disorder ◽  
Traumatic Stress ◽  
Stress Disorder ◽  
Anxiety And Depression ◽  
Long Term Memory ◽  
Post Traumatic Stress ◽  
Term Memory ◽  
Memory Impairments ◽  
Post Traumatic

AbstractPost-traumatic stress disorder (PTSD) is a debilitating psychopathological disease that is triggered by exposure to traumatic events. It is usually associated with substantial comorbidities, such as cognitive impairment, anxiety, and depression. Silymarin has been recently reported to exert neuroprotective activities against neurodegenerative diseases such as Alzheimerʼs and Parkinsonʼs diseases. Herein, the beneficial effects of silymarin in ameliorating PTSD-like symptoms such as memory impairments, anxiety, and depression were evaluated using a single-prolonged stress (SPS) rat model of PTSD. Male Wistar rats were randomly assigned into four groups: control, silymarin, SPS, or SPS + silymarin. Rats were administrated silymarin, 100 mg/kg i. p. for 4 wk. Rats in all groups were tested for short- and long-term memory in the radial arm water maze (RAWM), for anxiety-like behaviors using the open field test (OFT) and elevated plus maze (EPM) test, and for depression-like symptoms using the tail suspension test (TST). Conventional analyses of the RAWM, EPM, OFT, and TST were conducted using analysis of variance. Additionally, the anxiety-related behavior parameters of the EPM and OFT were entered to principal component analysis. Regression scores based on the first two extracted components, which accounted for 61% of the variance, were indicative of the anxiolytic activity of silymarin. Collectively, the results suggest that silymarin treatment prevents SPS-induced long-term memory impairments, anxiety, and depressive-like symptoms in rat models.

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