The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.

DEFINITION:

thalamus

A large ovoid mass in the posterior part of the diencephalon forming most of each lateral wall of the third ventricle, composed chiefly of gray substance and associated laminae of white substance. It is divided into anterior, medial, and lateral parts, each part containing groups of nuclei that function as relay centers for sensory impulses and cerebellar and basal ganglia projections to the cerebral cortex. The main groups of thalamic nuclei are the reticular, anterior, median, medial, medullary, intralaminar, ventrolateral, and posterior nuclei. Some authorities consider the subthalamus part of the thalamus and refer to it as the "ventral thalamus," calling the posterior part the "dorsal thalamus."