Seth Ruffins

A multimodal, multidimensional atlas of the C57BL/6J mouse brain

Strains of mice, through breeding or the disruption of normal genetic pathways, are widely used to model human diseases. Atlases are an invaluable aid in understanding the impact of such manipulations by providing a standard for comparison. We have developed a digital atlas of the adult C57BL/6J mouse brain as a comprehensive framework for storing and accessing the myriad types of information about the mouse brain. Our implementation was constructed using several different imaging techniques: magnetic resonance microscopy, blockface imaging, classical histology and immunohistochemistry. Along with raw and annotated images, it contains database management systems and a set of tools for comparing information from different techniques. The framework allows facile correlation of results from different animals, investigators or laboratories by establishing a canonical representation of the mouse brain and providing the tools for the insertion of independent data into the same space as the atlas. This tool will aid in managing the increasingly complex and voluminous amounts of information about the mammalian brain. It provides a framework that encompasses genetic information in the context of anatomical imaging and holds tremendous promise for producing new insights into the relationship between genotype and phenotype. We describe a suite of tools that enables the independent entry of other types of data, facile retrieval of information and straightforward display of images. Thus, the atlas becomes a framework for managing complex genetic and epigenetic information about the mouse brain. The atlas and associated tools may be accessed at http://www.loni.ucla.edu/MAP.

Digital Atlasing and Standardization in the Mouse Brain

Digital brain atlases are used in neuroscience to characterize the spatial organization of neuronal structures [1]–[3], for planning and guidance during neurosurgery [4], [5], and as a reference for interpreting other modalities such as gene expression or proteomic data [6]–[9]. The field of digital atlasing is extensive, and includes high quality brain atlases of the mouse [10], rat [11], rhesus macaque [12], human [13], [14], and several other model organisms. In addition to atlases based on histology, [11], [15], [16], magnetic resonance imaging [10], [17], and positron emission tomography [11], modern digital atlases often use probabilistic and multimodal techniques [18], [19], as well as sophisticated visualization software [20], [21]. Whether atlases involve detailed visualization of structures of a single or small group of specimens [6], [22], [23] or averages over larger populations [18], [24], much of the work in developing digital brain atlases is from the perspective of the user of a single resource. This is often due largely to the challenges of data generation, maintenance, and resources management [25], [26]. A more recent goal of many neuroscientists is to connect multiple and diverse resources to work in a collaborative manner using an atlas based framework [2], [19]. This vision is appealing as, ideally, researchers would be able to share their data and analyses with others, regardless of where they or the data are located. An important step in this direction is the specification of a common frame of reference across specimens and resources (either as coordinate, ontology, or region of interest) that is adopted by the community. In this perspective, we propose a collaborative digital atlasing framework for coordinating mouse brain research that allows access to data, tools, and analyses from multiple sources.

Digital Three-Dimensional Atlas of Quail Development Using High-Resolution MRI

We present an archetypal set of three-dimensional digital atlases of the quail embryo based on microscopic magnetic resonance imaging (μMRI). The atlases are composed of three modules: (1) images of fixed ex ovo quail, ranging in age from embryonic day 5 to 10 (e05 to e10); (2) a coarsely delineated anatomical atlas of the μMRI data; and (3) an organ system-based hierarchical graph linked to the anatomical delineations. The atlas is designed to be accessed using SHIVA, a free Java application. The atlas is extensible and can contain other types of information including anatomical, physiological, and functional descriptors. It can also be linked to online resources and references. This digital atlas provides a framework to place various data types, such as gene expression and cell migration data, within the normal three-dimensional anatomy of the developing quail embryo. This provides a method for the analysis and examination of the spatial relationships among the different types of information within the context of the entire embryo.

Towards a Tralfamadorian view of the embryo: multidimensional imaging of development

Biological problems such as embryonic development require tools to follow cell and tissue movements as well as the distribution of active genes. A variety of emerging imaging techniques offer the capability of fully rendering the three-dimensional structure of the embryo, and some offer the possibility of following changes directly over time. The data sets that result offer both new insights and new challenges. A framework of digital atlases will soon offer the integration of different imaging modalities and permit users to interact with multidimensional data sets.

MBAT: A scalable informatics system for unifying digital atlasing workflows

BackgroundDigital atlases provide a common semantic and spatial coordinate system that can be leveraged to compare, contrast, and correlate data from disparate sources. As the quality and amount of biological data continues to advance and grow, searching, referencing, and comparing this data with a researchers own data is essential. However, the integration process is cumbersome and time-consuming due to misaligned data, implicitly defined associations, and incompatible data sources. This work addressing these challenges by providing a unified and adaptable environment to accelerate the workflow to gather, align, and analyze the data.ResultsThe MouseBIRN Atlasing Toolkit (MBAT) project was developed as a cross-platform, free open-source application that unifies and accelerates the digital atlas workflow. A tiered, plug-in architecture was designed for the neuroinformatics and genomics goals of the project to provide a modular and extensible design. MBAT provides the ability to use a single query to search and retrieve data from multiple data sources, align image data using the users preferred registration method, composite data from multiple sources in a common space, and link relevant informatics information to the current view of the data or atlas. The workspaces leverage tool plug-ins to extend and allow future extensions of the basic workspace functionality. A wide variety of tool plug-ins were developed that integrate pre-existing as well as newly created technology into each workspace. Novel atlasing features were also developed, such as supporting multiple label sets, dynamic selection and grouping of labels, and synchronized, context-driven display of ontological data.ConclusionsMBAT empowers researchers to discover correlations among disparate data by providing a unified environment for bringing together distributed reference resources, a users image data, and biological atlases into the same spatial or semantic context. Through its extensible tiered plug-in architecture, MBAT allows researchers to customize all platform components to quickly achieve personalized workflows.

MRI in Developmental Biology and the Construction of Developmental Atlases

Microscopic magnetic resonance imaging (μMRI) is a noninvasive, nonoptical imaging modality that allows the entire volume of opaque specimens to be imaged. Because μMRI is not a destructive method, biologists are afforded anatomically unperturbed imagery of embryonic development and the ability to observe morphogenetic movements deep within optically inaccessible embryos. Compared with optical methods, μMRI data acquisition is slow, and image resolution is very low. This might suggest that μMRI is not viable for developmental studies. In this article, we discuss when μMRI is an appropriate imaging modality and how it has contributed to a richer understanding of embryonic development by allowing direct observation of dynamic processes in optically inaccessible regions of unperturbed embryos. We close the article with a discussion of μMRI for the construction of digital anatomical developmental atlases and how such atlases can be used.

Cell Interactions in the Sea Urchin Embryo

Publisher Summary This chapter discusses the cell–cell interactions that occur during sea urchin embryogenesis. The chapter classifies such interactions into two major categories: (1) cell–cell signaling events that regulate cell fate specification in the embryo and (2) cell interactions that modulate specific morphogenetic events independent of any apparent effects on cell fate specification. In some respects, this separation is artificial; the cellular properties that control morphogenesis are manifestations of the differentiated state of a cell, and interactions that regulate the fates of cells must necessarily also modulate their morphogenetic properties. Intercellular signaling is a key mechanism of cell fate specification in all multicellular animals. Even in those organisms that traditionally have been thought to rely primarily upon the segregation of maternal factors for the determination of cell fates, including ascidians and nematodes, numerous studies have revealed the importance of cell–cell interactions in regulating fate specification.

High-resolution, three-dimensional mapping of gene expression using GeneExpressMap (GEM)

The analysis of temporal and spatial patterns of gene expression is critically important for many kinds of developmental studies, including the construction of gene regulatory networks. Recently, multiplex, fluorescent, whole mount in situ hybridization (multiplex F-WMISH), applied in combination with confocal microscopy, has emerged as the method of choice for high-resolution, three-dimensional (3D) mapping of gene expression patterns in developing tissues. We have developed an image analysis tool, GeneExpressMap (GEM), that facilitates the rapid, 3D analysis of multiplex F-WMISH data at single-cell resolution. GEM assigns F-WMISH signal to individual cells based upon the proximity of cytoplasmic hybridization signal to cell nuclei. Here, we describe the features of GEM and, as a test of its utility, we use GEM to analyze patterns of regulatory gene expression in the non-skeletogenic mesoderm of the early sea urchin embryo. GEM greatly extends the power of multiplex F-WMISH for analyzing patterns of gene expression and is a valuable tool for gene network analysis and many other kinds of developmental studies.

Registration workflows for the creation of INCF digital atlas hubs

Workflows are being developed around specific data sharing use cases (Figure 2a). At this time, the use cases focus on 2D brain slice images (some sparsely, others highly sampled) of various modalities. The goal is to create tools, recommendations, and standard operating procedures to aid in the registration of data to a known standard atlas space (Figure 2b) and ability to share that data through INCF atlas hubs or to create new hubs (Figures 2c and 3). More information can be found at http://atlasing.incf.org/wiki/Workflow.

Related Methods for Three-Dimensional Imaging

The ability of confocal laser-scanning microscopy to collect stacks of optical sections has made three-dimensional (volumetric) imaging a standard analytical tool in experimental cell and developmental biology. Parallel developments in deconvolution techniques, especially as computational power increased and costs decreased, offered tools to make three-dimensional (3D) imaging from widefield as well as confocal microscopes possible. Despite the high spatial resolution provided by these 3D methods, they all suffer from a common limitation: light scattering in the specimen limits them to operating in the outer few hundred micrometers of the specimen.