TY - JOUR A1 - Palm, Christoph A1 - Axer, Markus A1 - Gräßel, David A1 - Dammers, Jürgen A1 - Lindemeyer, Johannes A1 - Zilles, Karl A1 - Pietrzyk, Uwe A1 - Amunts, Katrin T1 - Towards ultra-high resolution fibre tract mapping of the human brain BT - registration of polarised light images and reorientation of fibre vectors JF - Frontiers in Human Neuroscience N2 - Polarised light imaging (PLI) utilises the birefringence of the myelin sheaths in order to visualise the orientation of nerve fibres in microtome sections of adult human post-mortem brains at ultra-high spatial resolution. The preparation of post-mortem brains for PLI involves fixation, freezing and cutting into 100-μm-thick sections. Hence, geometrical distortions of histological sections are inevitable and have to be removed for 3D reconstruction and subsequent fibre tracking. We here present a processing pipeline for 3D reconstruction of these sections using PLI derived multimodal images of post-mortem brains. Blockface images of the brains were obtained during cutting; they serve as reference data for alignment and elimination of distortion artefacts. In addition to the spatial image transformation, fibre orientation vectors were reoriented using the transformation fields, which consider both affine and subsequent non-linear registration. The application of this registration and reorientation approach results in a smooth fibre vector field, which reflects brain morphology. PLI combined with 3D reconstruction and fibre tracking is a powerful tool for human brain mapping. It can also serve as an independent method for evaluating in vivo fibre tractography. KW - Bildgebendes Verfahren KW - Dreidimensionale Bildverarbeitung KW - Polarisiertes Licht KW - Gehirnkarte Y1 - 2010 U6 - https://doi.org/10.3389/neuro.09.009.2010 VL - 4 ER - TY - JOUR A1 - Axer, Markus A1 - Amunts, Katrin A1 - Gräßel, David A1 - Palm, Christoph A1 - Dammers, Jürgen A1 - Axer, Hubertus A1 - Pietrzyk, Uwe A1 - Zilles, Karl T1 - Novel Approach to the Human Connectome BT - Ultra-High Resolution Mapping of Fiber Tracts in the Brain JF - NeuroImage N2 - Signal transmission between different brain regions requires connecting fiber tracts, the structural basis of the human connectome. In contrast to animal brains, where a multitude of tract tracing methods can be used, magnetic resonance (MR)-based diffusion imaging is presently the only promising approach to study fiber tracts between specific human brain regions. However, this procedure has various inherent restrictions caused by its relatively low spatial resolution. Here, we introduce 3D-polarized light imaging (3D-PLI) to map the three-dimensional course of fiber tracts in the human brain with a resolution at a submillimeter scale based on a voxel size of 100 μm isotropic or less. 3D-PLI demonstrates nerve fibers by utilizing their intrinsic birefringence of myelin sheaths surrounding axons. This optical method enables the demonstration of 3D fiber orientations in serial microtome sections of entire human brains. Examples for the feasibility of this novel approach are given here. 3D-PLI enables the study of brain regions of intense fiber crossing in unprecedented detail, and provides an independent evaluation of fiber tracts derived from diffusion imaging data. KW - Connectome KW - Human brain KW - Method KW - Polarized light imaging KW - Tractography KW - Systems biology KW - Bildgebendes Verfahren KW - Dreidimensionale Bildverarbeitung KW - Polarisiertes Licht KW - Gehirnkarte Y1 - 2011 U6 - https://doi.org/10.1016/j.neuroimage.2010.08.075 VL - 54 IS - 2 SP - 1091 EP - 1101 ER -