Primary motor cortex in stroke: a functional MRI-guided proton MR spectroscopic study.

Area of Science:

• Neuroscience
• Biochemistry
• Medical Imaging

Background:

• Chronic stroke can lead to motor impairments.
• Understanding molecular changes in the brain post-stroke is crucial for recovery.
• Neuronal and glial metabolites may reflect functional changes in motor cortex.

Purpose of the Study:

• To investigate alterations in neuron-specific and glial-specific metabolites in the primary motor cortex (M1) of chronic stroke survivors.
• To determine if these metabolite changes correlate with clinical motor severity.
• To explore the utility of MR spectroscopy in quantifying these post-stroke changes.

Main Methods:

• Proton magnetic resonance spectroscopic imaging (1H-MRSI) was used to measure N-acetylaspartate, myo-inositol, and glutamate/glutamine.
• Measurements were taken in the primary motor cortex (M1) of 14 stroke survivors and 14 healthy controls.
• Functional MRI identified the hand representation area in M1 for metabolite analysis.

Main Results:

• Stroke survivors exhibited lower N-acetylaspartate and higher myo-inositol in both ipsilesional and contralesional M1 compared to controls.
• Significant correlations were observed between N-acetylaspartate and glutamate/glutamine.
• Ipsilesional N-acetylaspartate and glutamate/glutamine correlated positively with motor impairment; contralesional N-acetylaspartate correlated with time post-stroke.

Conclusions:

• Preliminary findings indicate altered neuronal-glial interactions in the spared M1 of stroke survivors.
• Metabolite alterations in the ipsilesional M1 are linked to stroke severity, while contralesional changes relate to stroke duration.
• MR spectroscopy shows promise for quantifying metabolite changes, aiding understanding of motor impairment post-stroke.