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Updated: Jun 16, 2026
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Standardized Data Acquisition for Neuromelanin-Sensitive Magnetic Resonance Imaging of the Substantia Nigra
Published on: September 8, 2021
Substantia nigra echomorphology and motor cortex excitability.
G Todd1, J L Taylor, D Baumann
1Discipline of Physiology, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA 5005, Australia.
Neuroimage
|February 2, 2010
Summary
Healthy older adults with substantia nigra (SN) hyperechogenicity show reduced motor cortex inhibition. This finding suggests SN echomorphology may indicate vulnerability to Parkinson's disease (PD) or subtle dopaminergic dysfunction.
Area of Science:
- Neuroimaging
- Neurophysiology
- Gerontology
Background:
- Substantia nigra (SN) hyperechogenicity on transcranial sonography is linked to Parkinson's disease (PD) risk.
- Its prevalence increases with age, suggesting a potential role in aging-related neurological changes.
Purpose of the Study:
- To investigate the relationship between SN echomorphology and motor cortex excitability in healthy older adults.
- To determine if SN hyperechogenicity is associated with altered intracortical inhibition.
Main Methods:
- Utilized transcranial sonography to assess SN echomorphology in 20 healthy older adults (72-84 years).
- Employed transcranial magnetic stimulation (TMS) to measure motor cortical excitability and intracortical inhibition over the first dorsal interosseus motor area.
- Compared individuals with normal SN echomorphology (n=10) to those with abnormal (hyperechogenic) SN (n=10).
Main Results:
- No significant differences in single-pulse TMS responses were found between groups.
- A significant difference emerged in the paired-pulse TMS paradigm: conditioned motor evoked potential amplitude was larger ipsilateral to the hyperechogenic SN.
- Healthy subjects with SN hyperechogenicity exhibited significantly less intracortical inhibition compared to controls.
Conclusions:
- SN hyperechogenicity in healthy individuals is associated with reduced motor cortex intracortical inhibition.
- This finding supports SN echomorphology as a potential vulnerability or state marker for subtle nigral dopaminergic dysfunction, characteristic of early PD changes.
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