title: Mapping somatosensory connectivity in adult mice using diffusion MRI tractography and super-resolution track density imaging.
abstract: In this study we combined ultra-high field diffusion MRI fiber tracking and super-resolution track density imaging (TDI) to map the relay locations and connectivity of the somatosensory pathway in paraformaldehyde fixed, C57Bl/6J mouse brains. Super-resolution TDI was used to achieve 20 μm isotropic resolution to inform the 3D topography of the relay locations including thalamic barreloids and brainstem barrelettes, not described previously using MRI methodology. TDI-guided mapping results for thalamo-cortical connectivity were consistent with thalamo-cortical projections labeled using virus mediated fluorescent protein expression. Trigemino-thalamic TDI connectivity maps were concordant with results obtained using anterograde dye tracing from brainstem to thalamus. Importantly, TDI mapping overcame the constraint of tissue distortion observed in mechanically sectioned tissue, enabling 3D reconstruction and long-range connectivity data. In conclusion, our results showed that diffusion micro-imaging at ultra-high field MRI revealed the stereotypical pattern of somatosensory connectivity and is a valuable tool to complement histologic methods, achieving 3D spatial preservation of whole brain networks for characterization in mouse models of human disease.
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Kay
authors.initials: K
authors.lastname: Richards
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Fernando
authors.initials: F
authors.lastname: Calamante
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Jacques-Donald
authors.initials: JD
authors.lastname: Tournier
authors.affiliation: Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Nyoman D
authors.initials: ND
authors.lastname: Kurniawan
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Farnoosh
authors.initials: F
authors.lastname: Sadeghian
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Retchford
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Gabriel Davis
authors.initials: GD
authors.lastname: Jones
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Reid
authors.affiliation: Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: David C
authors.initials: DC
authors.lastname: Reutens
authors.affiliation: Melbourne Brain Imaging Centre, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Roger
authors.initials: R
authors.lastname: Ordidge
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Alan
authors.initials: A
authors.lastname: Connelly
authors.affiliation: Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia; Centre for Neural Engineering, The University of Melbourne, Parkville, Victoria, Australia; ARC Centre of Excellence for Integrated Brain Function, The University of Melbourne, Parkville, Victoria, Australia. Electronic address: s.petrou@unimelb.edu.au.
authors.forename: Steven
authors.initials: S
authors.lastname: Petrou
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D038524:Diffusion Magnetic Resonance Imaging; D021621:Imaging, Three-Dimensional; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009434:Neural Pathways / Q000033:anatomy & histology; D013003:Somatosensory Cortex / Q000033:anatomy & histology*; D013788:Thalamus / Q000033:anatomy & histology*; D014278:Trigeminal Nuclei / Q000033:anatomy & histology*; D014738:Vibrissae
keywords: Connectivity; Fiber tracking; Mouse brain; Somatosensory pathway; Track-density imaging