Hippocampal CA3 Pyramidal Cells

Hippocampal CA3 Pyramidal Cells

Introduction

<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">Hippocampal CA3 Pyramidal Cells</th>
</tr>
<tr>
<td class="label">Taxonomy</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology (CL)</td>
<td>[CL:0000598](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000598)</td>
</tr>
<tr>
<td class="label">Database</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology</td>
<td>[CL:0000598](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000598)</td>
</tr>
</table>

Hippocampal Ca3 Pyramidal Cells is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

Hippocampal CA3 Pyramidal Cells

Introduction

<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">Hippocampal CA3 Pyramidal Cells</th>
</tr>
<tr>
<td class="label">Taxonomy</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology (CL)</td>
<td>[CL:0000598](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000598)</td>
</tr>
<tr>
<td class="label">Database</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology</td>
<td>[CL:0000598](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000598)</td>
</tr>
</table>

Hippocampal Ca3 Pyramidal Cells is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

CA3 pyramidal neurons are excitatory cells in the CA3 region of the hippocampus. They receive inputs from the dentate gyrus via mossy fibers and project to CA1 via Schaffer collaterals. [@kesner2019]

<!-- taxonomy-enrichment --> [@amaral2020]

<!-- multi-taxonomy-enrichment -->

Multi-Taxonomy Classification

Taxonomy Database Cross-References

Morphology & Electrophysiology

• Morphology: pyramidal neuron (source: Cell Ontology)
• Morphology can be inferred from Cell Ontology classification

PanglaoDB Marker Cross-References

• Unknown (PanglaoDB):

External Database Links

• [Cell Ontology (CL:0000598)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000598)
• [OBO Foundry (CL:0000598)](http://purl.obolibrary.org/obo/CL_0000598)
• [Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
• [CellxGene Census](https://cellxgene.cziscience.com/)
• [Human Cell Atlas](https://www.humancellatlas.org/)
• [PanglaoDB](https://panglaodb.se/)

Taxonomy & Classification

PanglaoDB Marker Cross-References

• Unknown (PanglaoDB):

External Database Links

• [Cell Ontology (CL:0000598)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000598)
• [OBO Foundry (CL:0000598)](http://purl.obolibrary.org/obo/CL_0000598)
• [Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
• [CellxGene Census](https://cellxgene.cziscience.com/)
• [PanglaoDB](https://panglaodb.se/)

Relevance to Neurodegeneration

• Mossy fiber boutons show early alterations in AD
• Vulnerable to excitotoxicity
• Involved in memory circuit dysfunction

Key Properties

• Extensive recurrent collateral connections
• Express high levels of NMDA and AMPA receptors
• Critical for pattern completion in memory recall

Connectivity

• Input: Mossy fibers from dentate gyrus granule cells
• Output: Schaffer collaterals to CA1, recurrent collaterals to other CA3 neurons

See Also

• [Cell-Types/Hippocampal-Pyramidal-Cells — This page](/cell-types)

Background

The study of Hippocampal Ca3 Pyramidal Cells has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development. [@hasselmo2020]

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions. [@liu2021]

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
• [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
• [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data

Molecular Markers

CA3 pyramidal neurons express distinctive molecular markers:

• CaMKIIα: Calcium/calmodulin-dependent protein kinase II alpha
• [Reelin**: Extracellular matrix glycoprotein critical for lamination](/genes/ar)
• Wnt2: Wingless-type MMTV integration site family member 2
• NeuroD1: Neurogenic differentiation factor 1
• KA1 (GRIK4): Kainate receptor subunit
• mGluR1: Metabotropic glutamate receptor type 1
• Acetylcholine muscarinic receptor M3

Electrophysiology

CA3 pyramidal neurons display unique electrophysiological features:

• Resting Membrane Potential: -60 to -65 mV
• Input Resistance: 50-150 MΩ
• Time Constant: 10-20 ms
• Action Potential Threshold: Approximately -50 mV
• Burst Firing: Intrinsic burst capability via calcium channels
• Afterdepolarization: Prominent afterdepolarization following bursts

Connectivity

Mossy Fiber Inputs

• High-frequency bursts: Granule cells fire in bursts, activating CA3
• Sparse coding: Each granule cell contacts ~15 CA3 pyramidal cells
• Plasticity: Mossy fiber-CA3 synapses show pronounced LTP

Associational Connections

• Recurrent collateral system: Extensive associational connections
• Pattern completion: Enables hippocampal memory consolidation
• Auto-associative network: Supports pattern separation/completion

Output Projections

• CA3 → CA1 (Schaffer collateral): Major hippocampal output
• CA3 → Subiculum: Direct entorhinal cortex relay
• CA3 → Septal nuclei: Cholinergic modulation feedback

Function

Memory Formation

• Pattern separation: Distinguishes similar memory representations
• Pattern completion: Retrieves complete memories from partial cues
• Spatial navigation: Grid-like place fields in 3D environment
• Context encoding: Binds sensory and emotional context

Computation

• Associative memory: Recurrent connections enable auto-association
• Predictive coding: CA3 predicts upcoming sensory information
• Memory consolidation: Transfers info from dentate to CA1

Disease Associations

Alzheimer's Disease

• CA3 particularly vulnerable to early tau pathology
• Loss of pattern completion ability early in AD
• Impaired spatial memory formation
• Hyperexcitability before neuron loss

Epilepsy

• CA3 is focus for hippocampal seizures
• Aberrant mossy fiber sprouting
• Recurrent excitation contributes to ictal activity
• Surgical removal of CA3 can prevent seizures

Memory Disorders

• CA3 dysfunction implicated in age-related memory decline
• Fragile X syndrome affects CA3 plasticity
• Schizophrenia shows CA3 abnormalities

Neurophysiology

Place Fields

• CA3 pyramidal cells have spatial firing fields
• Multiple place fields per neuron common
• Phase precession relative to theta oscillations
• Stability over weeks in familiar environments

Theta Oscillations

• CA3 neurons entrain to 4-8 Hz theta rhythm
• Theta phase codes spatial position
• Theta-gamma coupling supports memory encoding
• REM sleep theta associated with memory consolidation

Therapeutic Targets

Pharmacological

• mGluR1 antagonists: Reduce CA3 hyperexcitability
• Kainate receptor modulators: Alter network excitability
• Muscarinic agonists: Enhance memory consolidation

Genetic

• BDNF delivery: Supports CA3 neuron survival
• Reelin enhancement: May restore lamination

Surgical

• Selective CA3 ablation for epilepsy
• Hippocampal stimulation for memory enhancement

See Also

• [Hippocampus](/brain-regions/hippocampus)
• [Dentate Gyrus](/brain-regions/dentate-gyrus)
• CA1 Pyram-types/hippidal Cells
• Mossy Fibers](/brain-regions/hippocampus
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• Memory Consolidation