Functional Neuroimaging of Urine Storage and Voiding in Mice
These studies, were funded by an NIH P20 grant DK108276, to form a Resource Development Project within the BIDMC Department of Medicine’s Center for Interdisciplinary Research in Benign Urology.
This Project brings together Department of Radiology Magnetic Resonance Imaging (MRI) physicists and Department of Medicine Physiologists within BIDMC to develop, validate and disseminate methods for functional imaging of mouse brains during cystometrograms (Cystometry is a measurement of bladder filling and emptying).
Neuroimaging in humans who were voiding was pioneered by Gert Holstege’s group in the Netherlands during the 1990s and initially used Positron Emission Tomography (PET) measurements. Later studies shifted to the use of BOLD-MRI (Blood Oxygen Level Dependent MRI) which uses changes in blood oxygen levels detected by MRI to locate brain regions that are changing activation states. This is the primary method used in functional MRI (fMRI). A very good review of the findings in humans related to voiding can be found here.
Mice have become the most common model for research into human disease. Being mammals, mice share considerable anatomy, physiology and metabolism to humans. In addition, considerable efforts by thousands of researchers over the last 40 years has built a huge resource in the form of genetically modified mouse lines that can be used in many areas of research.
However, mice are small, very small, with small brains, thus posing a challenge for studies such as these using fMRI. Using the P20 funding method we have been successful in developing methods for performing fMRI on mice undergoing cystometry. We present some findings below and provide detailed methods on how data collected are analyzed that others may use to further their own studies. As always, there is room for further development and we will update our methods as new components become available.
Look for our first publication on these results in 2020.
We are indebted to Dr. Craig Ferris from Northeastern University for assistance in obtaining preliminary data using awake animals. Dr. Ferris’ information can be found at https://cos.northeastern.edu/people/craig-ferris/.