4-D imaging methods in vertebrate morphology
Brainerd, E.L.
These are exciting times in the field of vertebrate morphology. Imaging technologies such as CT scanning, MRI, ultrasound, and laser scanning confocal microscopy are opening up vast worlds of cross-sectional and three-dimensional anatomy. Studies of functional morphology, paleontology, and development are poised at the edge of a revolution in our ability to capture and quantify complex morphology and function in 4-D (three spatial dimensions plus time), and to integrate our understandings of function, development, and evolution. In this workshop I shall give a general overview of 3-D imaging methods, with particular attention to current limits in spatial and temporal resolution and suitability for in vivo imaging. Recent developments in microsource CT, high-field MRI, and high-frequency ultrasound have greatly increased the spatial resolution of these methods and made them suitable for use with developing embryos as well as larger specimens. Improvements in labeling techniques and contrast media are making it possible to tag specific tissues or gene expression in the context of the full 3-D morphology, thereby integrating developmental, genetic, and comparative approaches to the study of evolutionary morphology. Advances have been made in image acquisition speed, but the temporal resolution of true 3-D methods remains fairly poor (generally not more than 1 Hz), so 4-D imaging that could capture locomotion and other natural movements is currently unavailable. At the end of the presentation I will discuss "CTX Imaging", a method we are developing at Brown University for visualizing and measuring 4-D skeletal motion at up to 1000 Hz.
Ecology & Evolutionary Biology - Brown University