Comparative Anatomy of the Thalamus

Abstract

No book entitled The Thalamus can afford to restrict itself to the mammalian thalamus. One senses, however, that it would be wise to do so, for the field of comparative anatomy of the nonmammalian forebrain is one that has suffered from an absence of adequate experimental material, it has often been characterized by simplistic thinking about evolutionary matters, and it is fraught with controversy. A neuroscientist today can hardly utter the word homology without finding a half-dozen other neuroscientists at his throat. Homology in the evolutionary sense is extremely difficult to establish and existing vertebrate forms show such an enormous range of structural and functional adaptations in their forebrains, even within the same order, that many recent comparative neuro-anatomists have questioned whether it is relevant to search for common structural relationships. Certainly, no writer in the field today would seriously propose that the brains of existing nonmammalian vertebrates formed a scala naturae leading up to the brains of mammals.

Bring with you all the nymphes that you can heare Both of the rivers and the forrests greene, And of the sea that neighbors to her neare: All with gay girlands goodly wel beseene.

Edmund Spenser,Epithalamion