Cerebral stiffness changes during visual stimulation: Differential physiological mechanisms characterized by opposing...

Area of Science:

• Neuroimaging
• Biophysics
• Medical Physics

Background:

• Brain function relies on complex physiological and mechanical processes.
• Magnetic Resonance Elastography (MRE) offers a non-invasive method to assess tissue mechanical properties.
• Understanding brain mechanics during neural activity is crucial for diagnosing neurological conditions.

Purpose of the Study:

• To investigate cerebro-mechanical changes in healthy subjects during visual stimulation using functional intrinsic MRE (fiMRE).
• To correlate shear stiffness alterations with arterial dilation and BOLD fMRI signals.
• To explore differential mechanical responses in distinct visual cortex regions.

Main Methods:

• Performed fiMRE, Time of Flight angiography, and BOLD fMRI on 7 healthy subjects.
• Monitored shear stiffness and arterial dilation during prolonged visual stimulation.
• Analyzed stiffness changes in gray and white matter, and in regions adjacent to major arteries.

Main Results:

• Increased stiffness was observed nearly equally in white and gray matter.
• Decreased stiffness was significantly more prevalent in white matter.
• Significant reduction in shear stiffness near the Posterior Cerebral Artery (V1 region) correlated with vasodilation.
• Significant increase in shear stiffness near the Middle Temporal/V5 region was observed.

Conclusions:

• fiMRE can detect intrinsic cerebro-mechanical reactions to visual stimulation.
• The study demonstrates differential mechanical responses in distinct visual cortex regions.
• fiMRE provides insights into the interplay between neural activity, vascular changes, and tissue mechanics.