Methodological pipeline, refer to text for details. Abbreviations: CSF = Cerbrospinal fluid, CN = Caudate nucleus, GPe = External segment of the globus pallidus, GPi = Internal segment of the globus pallidus, MT = Magnetic transfer, NA = Nucleus accumbens, NNMF = Non-negative matrix factorisation, RN = Red nucleus, SN = Substantia nigra, STN = Subthalamic nucleus.