Researchers at ELKH’s Institute for Experimental Medicine and Semmelweis University have developed a new, unique procedure worldwide that allows CT and MRI measurements to be used to determine the location of instruments implanted in the brains of mice for experiments to understand normal and abnormal brain function with high accuracy before the experiment starts. The new procedure, based on an imaging technique, will significantly increase the efficiency of mouse experiments and thus greatly accelerate nervous system research. The new procedure developed by Bálint Király, Balázs Hangya, Krisztián Szigeti, Domokos Máthé and their colleagues was published in the highly prestigious Open Access Nature Communications.

A more accurate understanding of the normal and abnormal functioning of the brain is an extremely important task that can bring us closer to more effective treatment of serious diseases affecting humanity, such as Alzheimer’s and Parkinson’s diseases. This requires mouse experiments in which measuring devices even thinner than a hair, such as electrodes or optical fibers, are implanted in the brains of mice. However, due to the small size of the mouse brain, this procedure is a major challenge even for experienced surgeons.

Previously, histological tests were used to determine whether the implants were implanted in the appropriate location in the mouse brain after the experiments. However, thanks to the new procedure equivalent to the accuracy of histological tests, this examination can now be performed quickly and accurately before the start of the experiments, which increases the efficiency of mouse experiments and significantly accelerates nervous system research. One of the important features of the new procedure, based on in-depth knowledge of structural pet CT-MRI and neurophysiological methods, is that the location of implanted measuring devices is determined while keeping the radiation exposure associated with CT measurements below safe levels.

The researchers also assessed the possibilities for widespread application of the new procedure. Most of the leading English and American universities in the field of medical and biological sciences have access to the tools needed for the new procedure, and this is also the case for Hungarian medical universities.

The reviewers of the article published in Nature Communications noted, among other things, that by sharing their CT-MRI data, the authors also provided other researchers with the opportunity to examine individual variations in the shape of different brain areas.

Authors:

Bálint Király, Diána Balázsfi, Ildikó Horváth, Nicola Solari, Katalin Sviatkó, Katalin Lengyel, Eszter Birtalan, Magor Babos, Gergő Bagaméry, Domokos Máthé, Krisztián Szigeti & Balázs Hangya: In vivo localization of chronically implanted electrodes and optic fibers in mice.

https://www.nature.com/articles/s41467-020-18472-y

Pictures:

3 dimensional MRI image of the mouse brain

3 dimensional MRI image of the ventricles of the mouse brain

dapiMRI – Comparison between a histological slice under microscope (left) with the MRI image of the corresponding slice from the live animal (right)