The activity-dependent potentiation of the slow Ca 2+ -activated K + current regulates synaptic efficacy in rat CA1 pyramidal neurons

1999 ◽  
Vol 437 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Michel Borde ◽  
Christian Bonansco ◽  
W. Buño
Hippocampus ◽  
2004 ◽  
Vol 14 (8) ◽  
pp. 1011-1025 ◽  
Author(s):  
Didier Le Ray ◽  
David Fernández De Sevilla ◽  
Ana Belén Porto ◽  
Marco Fuenzalida ◽  
Washington Buño

2019 ◽  
Author(s):  
Tim P. Castello-Waldow ◽  
Ghabiba Weston ◽  
Alireza Chenani ◽  
Yonatan Loewenstein ◽  
Alon Chen ◽  
...  

SUMMARYNeurons undergoing activity-dependent plasticity represent experience and are functional for learning and recall thus they are considered cellular engrams of memory. Although increase in excitability and stability of structural synaptic connectivity have been implicated in the formation and persistance of engrams, the mechanisms bringing engrams into existence are still largely unknown. To investigate this issue, we tracked the dynamics of structural excitatory synaptic connectivity of hippocampal CA1 pyramidal neurons over two weeks using deep-brain two-photon imaging in live mice. We found that neurons that will prospectively become part of an engram display higher stability of connectivity than neurons that will not. A novel experience significantly stabilizes the connectivity of non-engram neurons. Finally, the density and survival of dendritic spines negatively correlates to freezing to the context but not to the tone in a trace fear conditioning learning paradigm.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Peter James Morgan ◽  
Romain Bourboulou ◽  
Caroline Filippi ◽  
Julie Koenig-Gambini ◽  
Jérôme Epsztein

In area CA1 of the hippocampus, the selection of place cells to represent a new environment is biased towards neurons with higher excitability. However, different environments are represented by orthogonal cell ensembles, suggesting that regulatory mechanisms exist. Activity-dependent plasticity of intrinsic excitability, as observed in vitro, is an attractive candidate. Here, using whole-cell patch-clamp recordings of CA1 pyramidal neurons in anesthetized rats, we have examined how inducing theta-bursts of action potentials affects their intrinsic excitability over time. We observed a long-lasting, homeostatic depression of intrinsic excitability which commenced within minutes, and, in contrast to in vitro observations, was not mediated by dendritic Ih. Instead, it was attenuated by the Kv1.1 channel blocker dendrotoxin K, suggesting an axonal origin. Analysis of place cells’ out-of-field firing in mice navigating in virtual reality further revealed an experience-dependent reduction consistent with decreased excitability. We propose that this mechanism could reduce memory interference.


2021 ◽  
Author(s):  
Caryn R Hale ◽  
Kirsty Sawicka ◽  
Kevin Mora ◽  
John J Fak ◽  
Jin Joo Kang ◽  
...  

Neurons are believed to rely on dendritic localization and translation of mRNAs in order to generate activity-dependent changes in the synaptic plasticity. Here, we develop a strategy combining compartment-specific CLIP and TRAP in conditionally tagged mice to precisely define the ribosome bound dendritic transcriptome of CA1 pyramidal neurons. This revealed transcripts that have differentially localized alternative 3′UTR and splicing isoforms. FMRP targets are overrepresented among dendritic mRNAs, and compartment-specific FMRP-CLIP defined 383 dendritic FMRP targets, and also allowed for segregation of whole-cell FMRP targets into functional modules that are locally regulated by FMRP. In the absence of FMRP, dendritic FMRP targets show increased ribosome association, consistent with reported roles for FMRP in translational repression. Together, the data support a model in which distinct patterns of FMRP localization allow it to differentially regulate the expression of nuclear proteins and synaptic proteins within different compartments of a single neuronal cell type.


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