1NATBRAINLAB, Department of Neuroimaging, King's College London, Institute of Psychiatry, London, United Kingdom; 2NIHR Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust, Kings College London, Institute of Psychiatry, London, United Kingdom; 3Department of Clinical Neuropathology, King's College Hospital, London, United Kingdom; 4NATBRAINLAB, Forensic and Neurodevelopmental Sciences, King's College London, Institute of Psychiatry, London, United Kingdom; 5McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States; 6Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States
Although a detailed cytoarchitectural description of the human brain by histology is long established, a comprehensive description of its connections ranging from major white matter pathways to small short-range fascicles remains elusive. Diffusion MR histology and micro-tractography offers a three-dimensional description of tissue cytoarchitecture at a mesoscale level. These methods produce quantitative information that, coupled with high-resolution visualisation of small fibres, fills the gap between large-scale network mapping and microscopic histology. We believe that this approach, applied to a fixed post-mortem cerebellum, represents an essential step forward in the understanding of the human brain and cerebellar connectivity and its functions.