Anatomy and three-dimensional reconstructions of the brain of a bottlenosedolphin (Tursiops truncatus) from magnetic resonance images

Cetacean (dolphin, whale, and porpoise) brains are among the least studied mammalian brains because of the formidability of collecting and histologica lly preparing such relatively rare and large specimens, Magnetic resonance imaging offers a means of observing the internal structure of the brain whe n traditional histological procedures are not practical. Furthermore, inter nal structures can be analyzed in their precise anatomic positions, which i s difficult to accomplish after the spatial distortions often accompanying histological processing. In this study, images of the brain of an adult bot tlenose dolphin, Tursiops truncatus, were scanned in the coronal plane at 1 48 antero-posterior levels. From these scans a computer-generated three-dim ensional model was constructed using the programs Voxel-View and VoxelMath (Vital Images, Inc.). This model, wherein details of internal and external morphology are represented in three-dimensional space, was then resectioned in orthogonal planes to produce corresponding series of virtual sections i n the horizontal and sagittal planes. Sections in all three planes display the sizes and positions of major neuroanatomical features such as the arran gement of cortical lobes and subcortical structures such as the inferior an d superior colliculi, and demonstrate the utility of MRI for neuroanatomica l investigations of dolphin brains. Anat Rec 264:397-414, 2001. (C) 2001 Wi ley-Liss, Inc.