title: 3D mapping of neuronal migration in the embryonic mouse brain with magnetic resonance microimaging.
abstract: A prominent feature of the developing mammalian brain is the widespread migration of neural progenitor (NP) cells during embryogenesis. A striking example is provided by NP cells born in the ventral forebrain of mid-gestation stage mice, which subsequently migrate long distances to their final positions in the cortex and olfactory bulb. Previous studies have used two-dimensional histological methods, making it difficult to analyze three-dimensional (3D) migration patterns. Unlike histology, magnetic resonance microimaging (micro-MRI) is a non-destructive, quantitative and inherently 3D imaging method for analyzing mouse embryos. To allow mapping of migrating NP cells with micro-MRI, cells were labeled in situ in the medial (MGE) and lateral (LGE) ganglionic eminences, using targeted in utero ultrasound-guided injection of micron-sized particles of iron-oxide (MPIO). Ex vivo micro-MRI and histology were then performed 5-6days after injection, demonstrating that the MPIO had magnetically labeled the migrating NP populations, which enabled 3D visualization and automated segmentation of the labeled cells. This approach was used to analyze the distinct patterns of migration from the MGE and LGE, and to construct rostral-caudal migration maps from each progenitor region. Furthermore, abnormal migratory phenotypes were observed in Nkx2.1(-/-) embryos, most notably a significant increase in cortical neurons derived from the Nkx2.1(-/-) LGE. Taken together, these results demonstrate that MPIO labeling and micro-MRI provide an efficient and powerful approach for analyzing 3D cell migration patterns in the normal and mutant mouse embryonic brain.
authors: Skirball Institute of Biomolecular Medicine, New York University School of Medicine, 540 First Ave, New York, NY 10016, USA.
authors: Abby E
authors: AE
authors: Deans
authors: Department of Radiology, New York University School of Medicine, 540 First Ave, New York, NY 10016, USA.
authors: Youssef Zaim
authors: YZ
authors: Wadghiri
authors: Skirball Institute of Biomolecular Medicine, New York University School of Medicine, 540 First Ave, New York, NY 10016, USA.
authors: Orlando
authors: O
authors: Aristizábal
authors: Skirball Institute of Biomolecular Medicine, New York University School of Medicine, 540 First Ave, New York, NY 10016, USA; Department of Radiology, New York University School of Medicine, 540 First Ave, New York, NY 10016, USA; Department of Pathology, New York University School of Medicine, 540 First Ave, New York, NY 10016, USA. Electronic address: Daniel.Turnbull@med.nyu.edu.
authors: Daniel H
authors: DH
authors: Turnbull
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000196:embryology*; D002465:Cell Movement; D005260:Female; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008813:Mice, Inbred ICR; D009474:Neurons / Q000166:cytology / Q000502:physiology*
keywords: LGE; Lateral ganglionic eminence; MGE; MPIO; MRI; Magnetic resonance imaging; Medial ganglionic eminence; Micron-sized particles of iron-oxide; UBM; Ultrasound biomicroscopy