Hello could you tell how can I get dataset of MRI brain and there are many sites provide dataset in muv extension. what is this format? because I have not find the appropriate software to open the muv files
Check out The Cancer Imaging Archive: http://www.cancerimagingarchive.net/. There's lots of brain images in DICOM format. DICOM has tons of freely available tools for viewing the images.
I used ADNI's data for my research, but, you need to register. You can find more such resources from here: https://en.wikipedia.org/wiki/List_of_neuroscience_databases