I need a standard brain connectivity matrix (CM) for healthy and pathological conditions, such as Alzheimer's disease, Down syndrom, etc. namely, a text or binary file which has all the connection strengths between some regions of interest (ROIs). I need this matrix, in addition to the MNI map of the ROIs used in the matrix. I couldn't find any database for it. It seems that each group measures these matrices by their own, rather than referring to a general database.

Is there a general database for brain connectivity that anyone can use and refer to? A matrix for the connections and physical locations of the default mode network (DMN) would also help.

Thanks in advance for your help!