Hippocampal Neurons Hub
<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">Hippocampal Neurons Hub</th>
</tr>
<tr>
<td class="label">Neuron Type</td>
<td>Specific Markers</td>
</tr>
<tr>
<td class="label">DG Granule</td>
<td>Prox1, Calbindin</td>
</tr>
<tr>
<td class="label">CA1 Pyramidal</td>
<td>Satb2, Calbindin</td>
</tr>
<tr>
<td class="label">CA3 Pyramidal</td>
<td>Calbindin, KA1</td>
</tr>
<tr>
<td class="label">PV+ Interneurons</td>
<td>Pvalb, GAD67</td>
</tr>
<tr>
<td class="label">SST+ Interneurons</td>
<td>Sst, GAD67</td>
</tr>
<tr>
<td class="label">Mossy Cells</td>
<td>Calretinin, GluR2-4</td>
</tr>
</table>
Overview
This hub page provides navigation to all hippocampal neuron types in the NeuroWiki knowledge base. The hippocampus is a bilateral seahorse-shaped brain structure (Greek: ἱππόκαμπος) critical for episodic memory formation, spatial navigation, and memory consolidation. Hippocampal neurons exhibit highly organized laminar architecture and are among the most vulnerable populations in Alzheimer's disease, with early and severe pathology.
Hippocampal Organization
The hippocampal formation comprises several subregions with distinct neuronal populations:
```mermaid
flowchart TD
subgraph Hippocampal_Formation["Hippocampal Formation"]
EC["Entorhinal Cortex"]
DG["Dentate Gyrus"]
CA3["CA3"]
CA2["CA2"]
CA1["CA1"]
SUB["Subiculum"]
...Hippocampal Neurons Hub
<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">Hippocampal Neurons Hub</th>
</tr>
<tr>
<td class="label">Neuron Type</td>
<td>Specific Markers</td>
</tr>
<tr>
<td class="label">DG Granule</td>
<td>Prox1, Calbindin</td>
</tr>
<tr>
<td class="label">CA1 Pyramidal</td>
<td>Satb2, Calbindin</td>
</tr>
<tr>
<td class="label">CA3 Pyramidal</td>
<td>Calbindin, KA1</td>
</tr>
<tr>
<td class="label">PV+ Interneurons</td>
<td>Pvalb, GAD67</td>
</tr>
<tr>
<td class="label">SST+ Interneurons</td>
<td>Sst, GAD67</td>
</tr>
<tr>
<td class="label">Mossy Cells</td>
<td>Calretinin, GluR2-4</td>
</tr>
</table>
Overview
This hub page provides navigation to all hippocampal neuron types in the NeuroWiki knowledge base. The hippocampus is a bilateral seahorse-shaped brain structure (Greek: ἱππόκαμπος) critical for episodic memory formation, spatial navigation, and memory consolidation. Hippocampal neurons exhibit highly organized laminar architecture and are among the most vulnerable populations in Alzheimer's disease, with early and severe pathology.
Hippocampal Organization
The hippocampal formation comprises several subregions with distinct neuronal populations:
Mermaid diagram (expand to render)
Hippocampal Neuron Hierarchy
Mermaid diagram (expand to render)
Principal Neuron Populations
Dentate Gyrus Granule Cells
- Dentate Gyrus Granule Cells — Main DG excitatory neurons
- Dentate Granule Epilepsy — Epileptogenesis mechanisms
Key characteristics:[@amaral2007]: Small, densely packed cell bodies in granule cell layer
[@claiborne1990]: Molecular layer dendrites receive perforant path input
[@henze2000]: Mossy fiber axons project to CA3 with giant boutons
[@ming2005]: Adult neurogenesis persists in subgranular zone
[@mchugh2007]: Gate function for hippocampal input (pattern separation)
CA Pyramidal Neurons
- Hippocampal CA1 Neurons — Most vulnerable to AD
- CA3 Pyramidal Neurons — Recurrent collaterals, pattern completion
- CA2 Pyramidal Neurons — Social memory, resistant to AD
CA1 characteristics:[@lorente1934]: Largest hippocampal subfield
[@shepherd1998]: Receives Schaffer collateral input from CA3
[@amaral1989]: Projects to subiculum and entorhinal cortex
[@schmidtkastner1991]: Most vulnerable to ischemia and AD
[@braak1995]: Early NFT accumulation (Braak stage I-II)
CA3 characteristics:
[@rebola2016]: Receives mossy fiber input from DG
[@rolls2013]: Extensive recurrent collaterals (autoassociative network)
[@ishizuka1990]: Projects via Schaffer collaterals to CA1
[@west1994]: Relatively preserved in early AD
Subiculum and Entorhinal Cortex
- Subiculum Pyramidal Neurons — Hippocampal output
- Entorhinal Stellate Cells — Layer II grid cells
Entorhinal cortex:[@gmezisla1996]: Layer II stellate cells are first AD target (Braak I)
[@hafting2005]: Grid cell spatial representation
[@witter2021]: Major cortical input/output gateway
Hippocampal Interneurons
PV+ Interneurons
- Basket Cells (Fast-Spiking)
- PV Interneurons
Functions: Perisomatic inhibition, gamma oscillation generation, feedforward inhibition
SST+ Interneurons
- SST Interneurons
- OLM (oriens-lacunosum moleculare) cells
Functions: Dendritic inhibition, theta rhythm modulation, feedback circuits
Other Interneurons
- Mossy Cells — DG hilar excitatory interneurons
- CCK Interneurons — Cannabinoid-modulated
- Calretinin Interneurons — Calbindin family
Molecular Markers
Disease Relevance
Alzheimer's Disease
The hippocampus is ground zero for early AD pathology:
[@braak2006]: Entorhinal cortex — First region affected (Braak I-II), layer II stellate cell loss
[@west1994a]: CA1 neurons — Severe early loss, NFT accumulation
[@selkoe2002]: Synaptic dysfunction — LTP impairment before cell death
[@west1990]: Granule cell sparing — DG relatively preserved early
[@small2011]: Memory impairment — Episodic memory loss correlates with CA1 pathology
Temporal Lobe Epilepsy
- Granule cell dispersion — Abnormal granule cell layer organization
- Mossy fiber sprouting — Recurrent excitatory circuits
- Interneuron loss — Reduced inhibition
- Hilar cell loss — Endfolium sclerosis
Other Conditions
- Schizophrenia — Hippocampal volume reduction, hyperactivity
- Depression — Reduced neurogenesis, stress effects
- PTSD — Contextual fear conditioning abnormalities
- Aging — Normal age-related changes vs pathology
Hippocampal Circuits
Trisynaptic Circuit
Perforant path — Entorhinal cortex layer II → DG granule cells
Mossy fibers — DG granule cells → CA3 pyramidal cells
Schaffer collaterals — CA3 → CA1 pyramidal cellsPlace Cell System
[@okeefe1971]: Place cells — CA1/CA3 neurons fire at specific locations
[@moser2017]: Grid cells — Entorhinal cortex hexagonal spatial representation
[@taube2007]: Head direction cells — Postsubiculum directional encoding
- Hippocampus Anatomy
- Memory Circuits
- Spatial Navigation
- LTP and Memory
- Entorhinal Cortex
- [Neurons](/cell-types/neurons) Major brain cell type
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- Temporal Lobe Epilepsy
External Links
- [Allen Brain Atlas - Hippocampus](https://portal.brain-map.org/explore/classes/multimodal-connectivity) — Connectivity data
- [Hippocampome](http://hippocampome.org/) — Hippocampal neuron encyclopedia
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/) — Biomedical literature