Anatomy and three-dimensional reconstructions of the brain of the white whale (Delphinapterus leucas) from magnetic resonance images

Magnetic resonance imaging offers a means of observing the internal structu re of the brain where traditional procedures of embedding, sectioning, stai ning, mounting, and microscopic examination of thousands of sections are no t practical. Furthermore, internal structures can be analyzed in their prec ise quantitative spatial interrelationships, which is difficult to accompli sh after the spatial distortions often accompanying histological processing . For these reasons, magnetic resonance imaging makes specimens that were t raditionally difficult to analyze, more accessible. In the present study, i mages of the brain of a white whale (Beluga) Delphinapterus leucas were sca nned in the coronal plane at 119 antero-posterior levels. From these scans, a computer-generated three-dimensional model was constructed using the pro grams VoxelView and VoxelMath (Vital Images, Inc.). This model, wherein det ails of internal and external morphology are represented in three-dimension al space, was then resectioned in orthogonal planes to produce correspondin g series of "virtual" sections in the horizontal and sagittal planes. Secti ons in all three planes display the sizes and positions of such structures as the corpus callosum, internal capsule, cerebral peduncles, cerebral vent ricles, certain thalamic nuclear groups, caudate nucleus, ventral striatum, pontine nuclei, cerebellar cortex and white matter, and all cerebral corti cal sulci and gyri. Anat Rec 262. 429-439, 2001. (C) 2001 Wiley-Liss, Inc.