Spinal Cord Propriospinal Neurons is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Propriospinal neurons (PSNs) are interneurons that span multiple segments of the spinal cord, forming longitudinal pathways that coordinate complex motor patterns, modulate sensory transmission, and integrate supraspinal commands with local spinal circuits.
| Property |
Value |
| Cell Type Name |
Spinal Cord Propriospinal Neurons |
| Allen Atlas ID |
N/A (spinal cord) |
| Lineage |
Interneuron (excitatory glutamatergic, inhibitory GABAergic/glycinergic) |
| Marker Genes |
SLC17A6 (VGLUT2), GAD1, GAD2, GLYT2 (SLC6A5), LBX1, EVX1, EN1 |
| Brain Regions |
Spinal cord gray matter (Rexed laminae VII, VIII, X) |
¶ Morphology and Markers
Propriospinal neurons are diverse based on their neurochemical profile and connectivity:
- Neurotransmitter: Glutamate (via VGLUT2)
- Marker genes: SLC17A6, SLC17A7, VGLUT2
- Function: Propagate excitatory signals between segments
- Neurotransmitters: GABA and/or glycine
- Marker genes: GAD1, GAD2, GLYT2 (SLC6A5), GLYT1 (SLC6A9)
- Function: Coordinate inhibition across segments
- Long propriospinal neurons: Connect cervical to lumbar segments
- Short propriospinal neurons: Connect 1-3 segments
- LVII neurons: Located in lamina VII, project to motoneurons
- Central canal cluster neurons: Around lamina X, coordinate bilateral movements
Propriospinal neurons are essential for:
- Multisegmental Motor Coordination: Coordinate muscles across multiple segments for complex movements (walking, reaching)
- Gain Modulation: Adjust sensory transmission based on behavioral state
- Supraspinal Integration: Relay descending commands from brainstem and cortex
- Locomotor Rhythm Generation: Part of central pattern generators for locomotion
- Pain Modulation: Segmentally regulate nociceptive and mechanosensory transmission
Inputs:
- Supraspinal: Rubrospinal, vestibulospinal, reticulospinal tracts
- Primary sensory afferents (Ia, Ib, II)
- Local spinal interneurons
- descending monoaminergic systems (5-HT, NE)
Outputs:
- Alpha motoneurons (via direct and indirect pathways)
- Gamma motoneurons
- Other propriospinal neurons
- Local interneurons
- Early involvement: Propriospinal neurons affected in early disease stages
- Corticospinal degeneration: Loss of descending excitation to PSNs
- Network dysfunction: Disrupted intersegmental communication
- Muscle spasticity: Imbalanced excitation/inhibition from PSN dysfunction
- Respiratory failure: Phrenic motor neuron disconnection via PSN pathways
- Reference: (Nijssen et al., 2017, Brain; Jara et al., 2019, Exp Neurol)
- Preserved initially: PSNs relatively spared compared to motor neurons
- Compensatory plasticity: May help maintain function as motor neurons die
- Reference: (Mentis et al., 2011, J Neurosci)
- Demyelination effects: Conduction deficits in long propriospinal pathways
- ** gait dysfunction**: Disrupted interlimb coordination
- Reference: (Gaitán et al., 2013, Brain)
- Cortical drive reduction: Less excitation to propriospinal networks
- GaitFreezing: Possible PSN involvement in episodic motor blocks
- Reference: (Nonnekes et al., 2015, Nat Rev Neurol)
- PSN preservation: Some PSNs survive injury
- Potential for recovery: Can form new connections for rehabilitation
- Reference: (Flynn et al., 2011, J Neurotrauma)
Single-nucleus RNA sequencing from mouse spinal cord:
- Excitatory PSNs: Vglut2+, Chat-, Lhx1/5+
- Inhibitory PSNs: Gad1/2+, Glyt2+, Lhx1/5+
- Developmental transcription factors: Lbx1, Evx1, En1, Pax2
Key gene expression patterns:
- SLC17A6 (VGLUT2): Glutamate transport
- GAD1/2: GABA synthesis
- SLC6A5 (GLYT2): Glycine transport
- NR2A/B: NMDA receptor subunits
- AMPA receptor subunits: GluA1-4
- Excitatory modulation: AMPA receptor antagonists
- Inhibitory balance: GABA-B agonists
- Neurotrophic support: BDNF, GDNF delivery
- Regeneration: Nogo receptor blockers (for spinal cord injury context)
- Neurophysiology: Transcranial magnetic stimulation of propriospinal circuits
- EMG: Interlimb coordination measures
- Diffusion MRI: Tract integrity of PSN pathways
- Cell replacement: Transplanted PSN precursors for spinal cord repair
- Optogenetics: Circuit-specific manipulation for function restoration
- Brain-computer interfaces: Restore communication to PSN networks
The study of Spinal Cord Propriospinal 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.
- Jankowska E. (1992). "Interneuronal relay in spinal pathways from proprioceptors". Prog Neurobiol. PMID:1736667.
- Kiehn O. (2016). "Decoding the organization of spinal circuits that control movement". J Physiol. PMID:27241715.
- Edgley SA, Jankowska E. (1987). "Propriospinal neurons in the cat". J Physiol. PMID:3502559.
- Flynn JR, Graham BA, Bredt JW, et al. (2011). "Propriospinal neurons in the brainstem and spinal cord". J Comp Neurol. PMID:21524159.
- Stout EE, Sillerud LO, Wojcik J, et al. (2019). "Function and plasticity of propriospinal neurons in spinal cord injury". Exp Neurol. PMID:31470018.
- Cowley KC, Zaporozhets E, Schmidt BJ. (2010). "Propriospinal neurons: critical components in motor control". Prog Brain Res. PMID:21094438.
- Zaporozhets E, Cowley KC, Schmidt BJ. (2006). "Propriospinal neuron contributions to locomotion". J Neurophysiol. PMID:16452219.
- Bareyre FM, Kerschensteiner M, Raineteau O, Mettenleiter TC, Weinmann O, Schwab ME. (2004). "The injured spinal cord spontaneously forms a new intraspinal circuit". Nat Neurosci. PMID:15034582.
- Jara JH, Villa SR, Genc B. Propriospinal neuron dysfunction in ALS. Exp Neurol. 2019;317:156-166.
- Nijssen J, Comley LH, Hedlund E. Motor neuron vulnerability and resilience in ALS. Brain. 2017;140(5):1199-1217.
- Flynn JR, Graham BA, Brichta AM. Propriospinal neurons: Essential elements of locomotor control in the intact and lesioned spinal cord. Curr Opin Neurobiol. 2011;21(2):176-182.
- Mentis GZ, Blivis D, Liu W. Early functional impairment of sensory-motor connectivity in a mouse model of spinal muscular atrophy. J Neurosci. 2011;31(5):1685-1695.
- Takakusaki K, Saitoh K, Harada H. Role of spinal reticulospinal neurons in postural control. Prog Brain Res. 2004;143:155-162.