Visualization of mouse barrel cortex using ex-vivo track density imaging.
We describe the visualization of the barrel cortex of the primary somatosensory area (S1) of ex vivo adult mouse brain with short-tracks track density imaging (stTDI). stTDI produced much higher definition of barrel structures than conventional fractional anisotropy (FA), directionally-encoded color FA maps, spin-echo T1- and T2-weighted imaging and gradient echo T1/T2*-weighted imaging. 3D high angular resolution diffusion imaging (HARDI) data were acquired at 48 micron isotropic resolution for a (3mm)(3) block of cortex containing the barrel field and reconstructed using stTDI at 10 micron isotropic resolution. HARDI data were also acquired at 100 micron isotropic resolution to image the whole brain and reconstructed using stTDI at 20 micron isotropic resolution. The 10 micron resolution stTDI maps showed exceptionally clear delineation of barrel structures. Individual barrels could also be distinguished in the 20 micron stTDI maps but the septa separating the individual barrels appeared thicker compared to the 10 micron maps, indicating that the ability of stTDI to produce high quality structural delineation is dependent upon acquisition resolution. Close homology was observed between the barrel structure delineated using stTDI and reconstructed histological data from the same samples. stTDI also detects barrel deletions in the posterior medial barrel sub-field in mice with infraorbital nerve cuts. The results demonstrate that stTDI is a novel imaging technique that enables three-dimensional characterization of complex structures such as the barrels in S1 and provides an important complementary non-invasive imaging tool for studying synaptic connectivity, development and plasticity of the sensory system.
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia. Electronic address: n.kurniawan@uq.edu.au.
Nyoman D
ND
Kurniawan
Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
Kay L
KL
Richards
ITEE, University of Queensland, Brisbane, Queensland, Australia.
Zhengyi
Z
Yang
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
David
D
She
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
Jeremy F P
JF
Ullmann
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
Randal X
RX
Moldrich
Queensland Brain Institute, Brisbane, Queensland, Australia.
Sha
S
Liu
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
Javier Urriola
JU
Yaksic
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
Gayeshika
G
Leanage
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
Irina
I
Kharatishvili
Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
Verena
V
Wimmer
Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, Victoria, Australia.
Fernando
F
Calamante
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
Graham J
GJ
Galloway
Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
Steven
S
Petrou
Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.
David C
DC
Reutens
D000818:Animals; D001931:Brain Mapping / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D013003:Somatosensory Cortex / Q000033:anatomy & histology*; D014738:Vibrissae / Q000294:innervation
Barrel cortex; CSD; Constrained spherical deconvolution; DEC; DTI; DWI; Diffusion tensor imaging; Diffusion weighted imaging; Diffusion-weighted imaging; Directionally encoded color; FA; FOD; Fiber orientation distribution; Fractional anisotropy; HARDI; High angular-resolution diffusion-weighted imaging; Infraorbital nerve cut; Magnetic resonance; Mouse brain; PMBSF; Posterior medial barrel sub-field; SH; Short-tracks track density imaging; Spherical harmonics; TDI; Track density imaging; Track-density imaging; VPM; Ventral posteromedial thalamic nucleus; stTDI