Cortical Neurons Hub
<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">Cortical Neurons Hub</th>
</tr>
<tr>
<td class="label">Neuron Type</td>
<td>Layer(s)</td>
</tr>
<tr>
<td class="label">IT Pyramidal</td>
<td>L2/3, L5, L6</td>
</tr>
<tr>
<td class="label">PT Pyramidal</td>
<td>L5b</td>
</tr>
<tr>
<td class="label">CT Pyramidal</td>
<td>L6</td>
</tr>
<tr>
<td class="label">Spiny Stellate</td>
<td>L4</td>
</tr>
<tr>
<td class="label">PV+ Interneurons</td>
<td>All</td>
</tr>
<tr>
<td class="label">SST+ Interneurons</td>
<td>L2-6</td>
</tr>
<tr>
<td class="label">VIP+ Interneurons</td>
<td>L2-6</td>
</tr>
<tr>
<td class="label">Neuron Type</td>
<td>Layer(s)</td>
</tr>
<tr>
<td class="label">IT Pyramidal</td>
<td>L2/3, L5, L6</td>
</tr>
<tr>
<td class="label">PT Pyramidal</td>
<td>L5b</td>
</tr>
<tr>
<td class="label">CT Pyramidal</td>
<td>L6</td>
</tr>
<tr>
<td class="label">Spiny Stellate</td>
<td>L4</td>
</tr>
<tr>
<td class="label">PV+ Interneurons</td>
<td>All</td>
</tr>
<tr>
<td class="label">SST+ Interneurons</td>
<td>L2-6</td>
</tr>
<tr>
<td class="label">VIP+ Interneurons</td>
<td>L2-6</td>
</tr>
</table>
Overview
This hub page provides navigation to all cortical neuron types in the NeuroWiki knowledge base. Cortical neurons are the primary computational units of the cerebral cortex, organized into six distinct layers with specialized cell types. The cortex underlies higher-order brain functions including perception, cognition, decision-making, and voluntary motor control. Cortical neurons are critically affected in Alzheimer's disease, frontotemporal dementia, and ALS (upper motor neurons).
Cortical Laminar Organization
The neocortex consists of six layers (I-VI) with distinct neuronal populations:
Mermaid diagram (expand to render)
Cortical Neuron Hierarchy
Mermaid diagram (expand to render)
Pyramidal Neurons
Layer 5 Pyramidal Neurons
- Cortical Pyramidal L5 — Main page
- Cortical Pyramidal Layer 5 — IT/PT subtypes
- Betz Cells — Giant pyramidal motor cortex neurons
Key characteristics:[@harris2015]:
Intratelencephalic (IT) — Project to striatum and contralateral cortex
[@molyneaux2007]:
Pyramidal tract (PT) — Project to brainstem and spinal cord (corticospinal)
[@rivaramunoz2009]:
Betz cells — Largest neurons, 30-100 μm soma, motor cortex layer Vb
[@arlotta2005]:
Molecular markers — CTIP2 (PT), FoxP2 (PT), Satb2 (IT)
[@browne2022]:
ALS vulnerability — Upper motor neuron degeneration in ALS
Layer 2/3 Pyramidal Neurons
- Cortical Pyramidal L2/3 — Main page
- Cortical Pyramidal Layer 2/3 — Corticocortical connections
Key characteristics:[@douglas2004]:
Intracortical connections — Association and commissural projections
[@mitchell2019]:
Transcallosal — Project via corpus callosum
[@belgard2011]:
Molecular markers — CUX1, CUX2, Satb2
[@kromer2009]:
AD vulnerability — Entorhinal LII stellate cells affected early
Layer 6 Pyramidal Neurons
- Cortical Layer 6 Neurons — Corticothalamic feedback
Key characteristics:[@guo2017]:
Corticothalamic — Project to thalamus, feedback modulation
[@thomson2010]:
Molecular markers — CTIP2, FoxP2, Tle4
Other Pyramidal Types
- Posterior Parietal Pyramidal — Spatial processing
Cortical Interneurons
PV+ Interneurons (Fast-Spiking)
- PV Interneurons — Main page
- Basket Cells Fast-Spiking — Perisomatic inhibition
- Large Basket Cells — Wide-field inhibition
- Chandelier Cells — Axon initial segment targeting
Key characteristics:[@markram2004]:
Fast-spiking — High-frequency non-accommodating firing
[@freund2007]:
Perisomatic inhibition — Control of output timing
[@cardin2009]:
Gamma oscillations — Critical for network synchrony
[@lima2013]:
AD vulnerability — PV+ loss correlates with cognitive decline
SST+ Interneurons (Dendritic-Targeting)
- SST Interneurons — Main page
- Martinotti cells, non-Martinotti cells
Key characteristics:[@silberberg2007]:
Dendritic inhibition — Modulate synaptic integration
[@wang2004]:
Martinotti cells — Target layer 1, feedback inhibition
[@pfeffer2013]:
Disinhibitory circuits — VIP-SST interactions
VIP+ Interneurons (Disinhibitory)
- VIP Interneurons — Main page
Key characteristics:[@lee2013]:
Disinhibitory function — Inhibit SST+ interneurons
[@fu2014]:
Arousal modulation — Cholinergic/serotonergic input
[@zhang2014]:
Attention circuits — State-dependent gating
Other Interneurons
- CCK Interneurons — Cannabinoid-modulated
- Calretinin Interneurons — Calcium buffering
- Layer 1 Cortical Interneurons — Neuromodulatory
Layer 4 Spiny Stellate Cells
- Spiny Stellate Cells — Main page
- Cortical Layer 4 Spiny Neurons — Thalamic input
Key characteristics:[@staiger2004]:
Thalamic relay — Primary recipients of thalamocortical input
[@petersen2019]:
Barrel cortex — Whisker representation in rodents
[@harris2014]:
Molecular markers — RORB, Reln
Molecular Markers
Disease Relevance
Alzheimer's Disease
- L2/3 Entorhinal — First affected (Braak I-II)
- CA1 hippocampal projection — Early loss
- PV+ interneurons — Reduced in AD, gamma disruption
- Layer 3/5 pyramidal — Tau pathology, neurodegeneration
Frontotemporal Dementia
- Layer 3/5 pyramidal — TDP-43, tau pathology
- Behavioral variant — Frontal cortex
- Primary progressive aphasia — Temporal cortex
ALS (Upper Motor Neurons)
- Betz cells — Degeneration in motor cortex
- Layer 5 PT — Corticospinal tract degeneration
- TDP-43 pathology — Nuclear depletion, cytoplasmic aggregation
Schizophrenia
- Interneuron dysfunction — PV+ cell loss, GABAergic deficit
- Layer 3/4 — Dendritic spine reduction
- Gamma oscillations — Impaired synchrony
- Neurons Overview
- Cortical Circuits
- Cortical Layers
- Frontal Cortex
- Motor Cortex
- [Neurons](/cell-types/neurons) Major brain cell type
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Frontotemporal Dementia](/diseases/frontotemporal-dementia)
- [ALS](/diseases/amyotrophic-lateral-sclerosis)
External Links
- [Allen Brain Atlas - Cell Types](https://portal.brain-map.org/atlases-and-data/rnaseq) — Single-cell transcriptomics
- [Blue Brain Project](https://www.epfl.ch/research/domains/bluebrain/) — Cortical microcircuit modeling
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/) — Biomedical literature
References
arlotta2005, Molecular controls of corticospinal motor neuron identity (2005)
belgard2011, Cortical gene expression (2011)
browne2022, Upper motor neuron degeneration in ALS (2022)
cardin2009, PV neurons and gamma oscillations (2009)
douglas2004, Neocortical microcircuits (2004)
freund2007, Perisomatic inhibition (2007)
fu2014, VIP interneuron modulation (2014)
guo2017, Cortical output layer 6 (2017)
harris2014, L4 spiny stellate transcription (2014)
harris2015, Neocortical neuron types (2015)
kromer2009, Layer 2/3 pyramidal neuron vulnerability in AD (2009)
lee2013, VIP interneurons (2013)
lima2013, PV interneurons in AD (2013)
markram2004, Interneurons of the neocortex (2004)
mitchell2019, Corticocortical communication (2019)
molyneaux2007, Neuronal subtype specification in the cerebral cortex (2007)
petersen2019, Barrel cortex (2019)
pfeffer2013, Disinhibition in cortical circuits (2013)
rivaramunoz2009, Betz cells (2009)
silberberg2007, SST interneuron disynaptic inhibition (2007)
staiger2004, Spiny stellate cells (2004)
thomson2010, Layer 6 connectivity (2010)
wang2004, Martinotti cells (2004)
zhang2014, VIP interneurons and attention (2014flowchart TD
subgraph Cortical_Layers["Cortical Layers"]
L1["Layer I<br/>Molecular Layer"]
L23["Layer II/III<br/>External Granular"]
L4["Layer IV<br/>Internal Granular"]
L5["Layer V<br/>Internal Pyramidal"]
L6["Layer VI<br/>Multiform"]
subgraph L1_cells["L1 Cells"]
L1A["Interneurons (Cajal-Retzius)"]
end
subgraph L23_cells["L2/3 Cells"]
L23A["Pyramidal Neurons (Corticocortical)"]
L23_INT["Interneurons"]
end
subgraph L4_cells["L4 Cells"]
L4A["Spiny Stellate Cells (Thalamic Input)"]
L4_INT["Interneurons"]
end
subgraph L5_cells["L5 Cells"]
L5_PT["Pyramidal Tract<br/>Subcortical Output"]
L5_IT["Intratelencephalic"]
L5_BETZ["Betz Cells<br/>Motor Cortex"]
end
subgraph L6_cells["L6 Cells"]
L6_CT["Corticothalamic<br/>Feedback"]
L6_INT["Interneurons"]
end
end
Cortical Neuron Hierarchy
Mermaid diagram (expand to render)
Pyramidal Neurons
Layer 5 Pyramidal Neurons
- Cortical Pyramidal L5 — Main page
- Cortical Pyramidal Layer 5 — IT/PT subtypes
- Betz Cells — Giant pyramidal motor cortex neurons
Key characteristics:[@harris2015]:
Intratelencephalic (IT) — Project to striatum and contralateral cortex
[@molyneaux2007]:
Pyramidal tract (PT) — Project to brainstem and spinal cord (corticospinal)
[@rivaramunoz2009]:
Betz cells — Largest neurons, 30-100 μm soma, motor cortex layer Vb
[@arlotta2005]:
Molecular markers — CTIP2 (PT), FoxP2 (PT), Satb2 (IT)
[@browne2022]:
ALS vulnerability — Upper motor neuron degeneration in ALS
Layer 2/3 Pyramidal Neurons
- Cortical Pyramidal L2/3 — Main page
- Cortical Pyramidal Layer 2/3 — Corticocortical connections
Key characteristics:[@douglas2004]:
Intracortical connections — Association and commissural projections
[@mitchell2019]:
Transcallosal — Project via corpus callosum
[@belgard2011]:
Molecular markers — CUX1, CUX2, Satb2
[@kromer2009]:
AD vulnerability — Entorhinal LII stellate cells affected early
Layer 6 Pyramidal Neurons
- Cortical Layer 6 Neurons — Corticothalamic feedback
Key characteristics:[@guo2017]:
Corticothalamic — Project to thalamus, feedback modulation
[@thomson2010]:
Molecular markers — CTIP2, FoxP2, Tle4
Other Pyramidal Types
- Posterior Parietal Pyramidal — Spatial processing
Cortical Interneurons
PV+ Interneurons (Fast-Spiking)
- PV Interneurons — Main page
- Basket Cells Fast-Spiking — Perisomatic inhibition
- Large Basket Cells — Wide-field inhibition
- Chandelier Cells — Axon initial segment targeting
Key characteristics:[@markram2004]:
Fast-spiking — High-frequency non-accommodating firing
[@freund2007]:
Perisomatic inhibition — Control of output timing
[@cardin2009]:
Gamma oscillations — Critical for network synchrony
[@lima2013]:
AD vulnerability — PV+ loss correlates with cognitive decline
SST+ Interneurons (Dendritic-Targeting)
- SST Interneurons — Main page
- Martinotti cells, non-Martinotti cells
Key characteristics:[@silberberg2007]:
Dendritic inhibition — Modulate synaptic integration
[@wang2004]:
Martinotti cells — Target layer 1, feedback inhibition
[@pfeffer2013]:
Disinhibitory circuits — VIP-SST interactions
VIP+ Interneurons (Disinhibitory)
- VIP Interneurons — Main page
Key characteristics:[@lee2013]:
Disinhibitory function — Inhibit SST+ interneurons
[@fu2014]:
Arousal modulation — Cholinergic/serotonergic input
[@zhang2014]:
Attention circuits — State-dependent gating
Other Interneurons
- CCK Interneurons — Cannabinoid-modulated
- Calretinin Interneurons — Calcium buffering
- Layer 1 Cortical Interneurons — Neuromodulatory
Layer 4 Spiny Stellate Cells
- Spiny Stellate Cells — Main page
- Cortical Layer 4 Spiny Neurons — Thalamic input
Key characteristics:[@staiger2004]:
Thalamic relay — Primary recipients of thalamocortical input
[@petersen2019]:
Barrel cortex — Whisker representation in rodents
[@harris2014]:
Molecular markers — RORB, Reln
Molecular Markers
Disease Relevance
Alzheimer's Disease
- L2/3 Entorhinal — First affected (Braak I-II)
- CA1 hippocampal projection — Early loss
- PV+ interneurons — Reduced in AD, gamma disruption
- Layer 3/5 pyramidal — Tau pathology, neurodegeneration
Frontotemporal Dementia
- Layer 3/5 pyramidal — TDP-43, tau pathology
- Behavioral variant — Frontal cortex
- Primary progressive aphasia — Temporal cortex
ALS (Upper Motor Neurons)
- Betz cells — Degeneration in motor cortex
- Layer 5 PT — Corticospinal tract degeneration
- TDP-43 pathology — Nuclear depletion, cytoplasmic aggregation
Schizophrenia
- Interneuron dysfunction — PV+ cell loss, GABAergic deficit
- Layer 3/4 — Dendritic spine reduction
- Gamma oscillations — Impaired synchrony
- Neurons Overview
- Cortical Circuits
- Cortical Layers
- Frontal Cortex
- Motor Cortex
- [Neurons](/cell-types/neurons) Major brain cell type
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Frontotemporal Dementia](/diseases/frontotemporal-dementia)
- [ALS](/diseases/amyotrophic-lateral-sclerosis)
External Links
- [Allen Brain Atlas - Cell Types](https://portal.brain-map.org/atlases-and-data/rnaseq) — Single-cell transcriptomics
- [Blue Brain Project](https://www.epfl.ch/research/domains/bluebrain/) — Cortical microcircuit modeling
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/) — Biomedical literature
References
arlotta2005, Molecular controls of corticospinal motor neuron identity (2005)
belgard2011, Cortical gene expression (2011)
browne2022, Upper motor neuron degeneration in ALS (2022)
cardin2009, PV neurons and gamma oscillations (2009)
douglas2004, Neocortical microcircuits (2004)
freund2007, Perisomatic inhibition (2007)
fu2014, VIP interneuron modulation (2014)
guo2017, Cortical output layer 6 (2017)
harris2014, L4 spiny stellate transcription (2014)
harris2015, Neocortical neuron types (2015)
kromer2009, Layer 2/3 pyramidal neuron vulnerability in AD (2009)
lee2013, VIP interneurons (2013)
lima2013, PV interneurons in AD (2013)
markram2004, Interneurons of the neocortex (2004)
mitchell2019, Corticocortical communication (2019)
molyneaux2007, Neuronal subtype specification in the cerebral cortex (2007)
petersen2019, Barrel cortex (2019)
pfeffer2013, Disinhibition in cortical circuits (2013)
rivaramunoz2009, Betz cells (2009)
silberberg2007, SST interneuron disynaptic inhibition (2007)
staiger2004, Spiny stellate cells (2004)
thomson2010, Layer 6 connectivity (2010)
wang2004, Martinotti cells (2004)
zhang2014, VIP interneurons and attention (2014)