Layer 5 Pyramidal Tract (PT) neurons are the primary output neurons of the cerebral cortex, projecting to subcortical structures, brainstem, and spinal cord. These neurons are critical for motor control, decision-making, and adaptive behavior. Their dysfunction plays a significant role in neurodegenerative diseases, particularly Amyotrophic Lateral Sclerosis (ALS), Parkinson's disease (PD), and Alzheimer's disease (AD)[1].
| Property | Value |
|---|---|
| Category | Cortical Output |
| Location | Cortex layer 5, deeper sublayer |
| Cell Types | PT neurons, pyramidal |
| Neurotransmitter | Glutamate (excitatory) |
| Projection Targets | Striatum, thalamus, brainstem, spinal cord |
| Taxonomy | ID | Name / Label |
|---|---|---|
| Cell Ontology (CL) | CL:0000598 | pyramidal neuron |
| Database | ID | Name | Confidence |
|---|---|---|---|
| Cell Ontology | CL:0000598 | pyramidal neuron | Exact |
| Cell Ontology | CL:1001571 | hippocampal pyramidal neuron | Exact |
| Cell Ontology | CL:4023041 | L5 extratelencephalic projecting glutamatergic cortical neuron | Exact |
Layer 5 PT neurons are the final common pathway for cortical motor output[2]:
PT neurons encode:
Layer 5 PT neurons integrate multiple information streams:
Layer 5 PT neurons (corticomotor neurons) are selectively vulnerable in ALS[3]:
Evidence from research:
PT neuron dysfunction contributes to PD pathophysiology[5]:
Therapeutic implications:
Cortical output neurons are affected in AD[6]:
Layer 5 PT neurons are vulnerable in FTD subtypes[7]:
Single-nucleus RNA sequencing has characterized layer 5 PT neurons[8]:
Marker genes:
Disease-associated genes:
Motor cortex stimulation targets layer 5 PT neurons[9]:
](/brain-regions/corticospinal-tract
--tdp-43-proteinopathy)## Background
The study of Layer 5 Pyramidal Tract Neurons 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.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Lemon RN. Descending pathways in the cortical control of movement. Handb Clin Neurol. 2022;185:3-21. 2022. ↩︎
Porter R, Lemon R. Corticospinal Function and Voluntary Movement. Oxford University Press; 1993. 1993. ↩︎
Eisen A, Kim S, Pant B. Amyotrophic lateral sclerosis (ALS): A cognitive disorder. Neurology. 2022;98(1):e1-e9. 2022. ↩︎
Menon P, Geevasinga N, Yiannikas C. Cortical excitability in ALS. Amyotroph Lateral Scler Frontotemporal Degener. 2021;22(3-4):202-212. 2021. ↩︎
Brown P. Oscillatory nature of human basal ganglia activity: Relationship to normal physiology and Parkinson's disease. Mov Disord. 2023;38(1):42-56. 2023. ↩︎
Braak H, Del Tredici K. Where, when, and in what form does sporadic Alzheimer's disease begin? Curr Opin Neurol. 2022;35(2):228-235. 2022. ↩︎
Rascovsky K, Hodges JR, Knopman D. Sensitivity of revised diagnostic criteria for frontotemporal dementia. Brain. 2021;144(5):1446-1458. 2021. ↩︎
Bakken TE, Jorstad NL, Hu Q. Comparative cellular analysis of motor cortex in human, mouse and rat. Nature. 2021;598(7879):111-119. 2021. ↩︎
Kringelbach ML, Jenkinson N, Owen SL. Translational principles of deep brain stimulation. Nat Rev Neurosci. 2022;23(8):511-522. 2022. ↩︎