Microbubble Track-based Functional Ultrasound Localization Microscopy in Awake Mice.

Area of Science:

• Neuroimaging
• Ultrasound technology
• Rodent brain studies

Background:

• Functional neuroimaging tools like functional ultrasound (fUS) and functional ultrasound localization microscopy (fULM) are crucial for studying rodent brain activity.
• Existing methods face a trade-off between functional imaging sensitivity and spatial resolution.
• fUS offers high sensitivity but limited resolution, while fULM provides super-resolution at the cost of sensitivity.

Purpose of the Study:

• To develop a novel microbubble (MB) track-based method to enhance the functional imaging sensitivity of fULM.
• To improve the detection of neural activities without compromising the high spatial resolution of fULM.
• To enable faster and more efficient functional brain imaging in rodents.

Main Methods:

• Developed a functional correlation analysis using MB movement tracks instead of individual centroid locations to overcome signal sparsity.
• Implemented indwelling jugular vein catheters for fULM imaging in awake mice to boost functional sensitivity.
• Utilized whisker stimulation experiments to validate the enhanced technique.

Main Results:

• The novel MB track-based method significantly enhanced the functional imaging sensitivity of fULM.
• High spatial resolution was maintained while improving functional sensitivity.
• Significantly activated brain regions were detected in fewer than five stimulation cycles (5 minutes), reducing acquisition time by over 50%.

Conclusions:

• The proposed techniques successfully address the sensitivity-resolution compromise in fULM.
• This advancement offers a more efficient and sensitive neuroimaging tool for studying brain activity in rodents.
• The method has the potential to accelerate neuroscience research by reducing experimental time.