scholarly journals Constitutive activation of CREB in mice enhances temporal association learning and increases hippocampal CA1 neuronal spine density and complexity

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Tatsurou Serita ◽  
Hotaka Fukushima ◽  
Satoshi Kida
Keyword(s):  
Temporal Association ◽  
Spine Density ◽  
Constitutive Activation ◽  
Association Learning ◽  
Hippocampal Ca1

scholarly journals Entorhinal cortical Island cells regulate temporal association learning with long trace period

2021 ◽  
Vol 28 (9) ◽  
pp. 319-328
Author(s):  
Jun Yokose ◽  
William D. Marks ◽  
Naoki Yamamoto ◽  
Sachie K. Ogawa ◽  
Takashi Kitamura
Keyword(s):  
Fear Conditioning ◽  
Critical Role ◽  
Pyramidal Cells ◽  
Temporal Association ◽  
Association Learning ◽  
Trace Fear Conditioning ◽  
Dorsal Hippocampal ◽  
Neural Input ◽  
Hippocampal Ca1 ◽  
Trace Fear

Temporal association learning (TAL) allows for the linkage of distinct, nonsynchronous events across a period of time. This function is driven by neural interactions in the entorhinal cortical–hippocampal network, especially the neural input from the pyramidal cells in layer III of medial entorhinal cortex (MECIII) to hippocampal CA1 is crucial for TAL. Successful TAL depends on the strength of event stimuli and the duration of the temporal gap between events. Whereas it has been demonstrated that the neural input from pyramidal cells in layer II of MEC, referred to as Island cells, to inhibitory neurons in dorsal hippocampal CA1 controls TAL when the strength of event stimuli is weak, it remains unknown whether Island cells regulate TAL with long trace periods as well. To understand the role of Island cells in regulating the duration of the learnable trace period in TAL, we used Pavlovian trace fear conditioning (TFC) with a 60-sec long trace period (long trace fear conditioning [L-TFC]) coupled with optogenetic and chemogenetic neural activity manipulations as well as cell type-specific neural ablation. We found that ablation of Island cells in MECII partially increases L-TFC performance. Chemogenetic manipulation of Island cells causes differential effectiveness in Island cell activity and leads to a circuit imbalance that disrupts L-TFC. However, optogenetic terminal inhibition of Island cell input to dorsal hippocampal CA1 during the temporal association period allows for long trace intervals to be learned in TFC. These results demonstrate that Island cells have a critical role in regulating the duration of time bridgeable between associated events in TAL.

Anterior thalamic lesions reduce spine density in both hippocampal CA1 and retrosplenial cortex, but enrichment rescues CA1 spines only

Hippocampus ◽  
2014 ◽  
Vol 24 (10) ◽  
pp. 1232-1247 ◽  
Author(s):  
Bruce C. Harland ◽  
David A. Collings ◽  
Neil McNaughton ◽  
Wickliffe C. Abraham ◽  
John C. Dalrymple-Alford
Keyword(s):  
Retrosplenial Cortex ◽  
Spine Density ◽  
Hippocampal Ca1 ◽  
Thalamic Lesions

scholarly journals EphB2 receptor cell-autonomous forward signaling mediates auditory memory recall and learning-driven spinogenesis

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Asghar Talebian ◽  
Mark Henkemeyer
Keyword(s):  
Auditory Cortex ◽  
Memory Loss ◽  
Kinase Domain ◽  
Auditory Memory ◽  
Tyrosine Kinase Domain ◽  
Memory Recall ◽  
Neural Activation ◽  
Spine Density ◽  
Synaptic Interactions ◽  
Hippocampal Ca1

Abstract While ephrin-B ligands and EphB receptors are expressed to high levels in the learning centers of the brain, it remains largely unknown how their trans-synaptic interactions contribute to memory. We find that EphB2 forward signaling is needed for contextual and sound-evoked memory recall and that constitutive over-activation of the receptor’s intracellular tyrosine kinase domain results in enhanced memory. Loss of EphB2 expression does not affect the number of neurons activated following encoding, although a reduction of neurons activated after the sound-cued retrieval test was detected in the auditory cortex and hippocampal CA1. Further, spine density and maturation was reduced in the auditory cortex of mutants especially in the neurons that were dual-activated during both encoding and retrieval. Our data demonstrates that trans-synaptic ephrin-B-EphB2 interactions and forward signaling facilitate neural activation and structural plasticity in learning-associated neurons involved in the generation of memories.

scholarly journals Comparative 2D and 3D Ultrastructural Analyses of Dendritic Spines from CA1 Pyramidal Neurons in the Mouse Hippocampus

2021 ◽  
Vol 22 (3) ◽  
pp. 1188
Author(s):  
Maria Nicol Colombo ◽  
Greta Maiellano ◽  
Sabrina Putignano ◽  
Lucrezia Scandella ◽  
Maura Francolini
Keyword(s):  
Pyramidal Neurons ◽  
Brain Connectivity ◽  
Three Dimensional ◽  
Excitatory Synapses ◽  
Spine Density ◽  
Functional Impairments ◽  
Small Complex ◽  
Hippocampal Ca1 ◽  
3D Em ◽  
2D And 3D

Three-dimensional (3D) reconstruction from electron microscopy (EM) datasets is a widely used tool that has improved our knowledge of synapse ultrastructure and organization in the brain. Rearrangements of synapse structure following maturation and in synaptic plasticity have been broadly described and, in many cases, the defective architecture of the synapse has been associated to functional impairments. It is therefore important, when studying brain connectivity, to map these rearrangements with the highest accuracy possible, considering the affordability of the different EM approaches to provide solid and reliable data about the structure of such a small complex. The aim of this work is to compare quantitative data from two dimensional (2D) and 3D EM of mouse hippocampal CA1 (apical dendrites), to define whether the results from the two approaches are consistent. We examined asymmetric excitatory synapses focusing on post synaptic density and dendritic spine area and volume as well as spine density, and we compared the results obtained with the two methods. The consistency between the 2D and 3D results questions the need—for many applications—of using volumetric datasets (costly and time consuming in terms of both acquisition and analysis), with respect to the more accessible measurements from 2D EM projections.

scholarly journals Chronic stress and a cyclic regimen of estradiol administration separately facilitate spatial memory: Relationship with hippocampal CA1 spine density and dendritic complexity.

2012 ◽  
Vol 126 (1) ◽  
pp. 142-156 ◽  
Author(s):  
Cheryl D. Conrad ◽  
Katie J. McLaughlin ◽  
Thu N. Huynh ◽  
Mariam El-Ashmawy ◽  
Michelle Sparks
Keyword(s):  
Spatial Memory ◽  
Chronic Stress ◽  
Spine Density ◽  
Hippocampal Ca1 ◽  
Dendritic Complexity

scholarly journals P3-380: Dendritic spine density deficits in the hippocampal CA1 region of young Tg2576 mice are ameliorated with the PDE9A inhibitor PF-04447943

2010 ◽  
Vol 6 ◽  
pp. S563-S564 ◽  
Author(s):  
Robin J. Kleiman ◽  
Thomas A. Lanz ◽  
James E. Finley ◽  
Susan E. Bove ◽  
Mark J. Majchrzak ◽  
...  
Keyword(s):  
Dendritic Spine ◽  
Spine Density ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Dendritic Spine Density ◽  
Hippocampal Ca1 ◽  
Tg2576 Mice
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