I. An experimental study of thalamic connections in the rat

Abstract

With the exception of the work of von Monakow (1895), Probst (1900), Wallenberg (1900), Sachs (1909) and Glorieux (1929), experimental observations on the connections of thalamic nuclei are isolated and scattered in the literature of neurology. Recent studies of the structure of the mammalian thalamus, based on the examination of normal material, have led to a much more complete definition of the nuclear components of the thalamus. Hence the time is ripe for a renewed investigation by experimental methods of this important part of the brain. The difficulties of applying to the thalamus the method of study by Marchi degeneration are, obviously, great, because it is not easy to produce isolated lesions of the thalamus without serious injury to adjacent parts of the brain. It is desirable that the experimental material should be examined as extensively as possible in serial sections so that the precise limit of the lesion may be ascertained. From this point of view it is of advantage to use the brain of a small mammal. In selecting the albino rat for experiments, it has been borne in mind that the diencephalon of this laboratory animal has been studied anatomically in considerable detail by Gurdjian (1927), while the cerebral cortex has been submitted to a very complete survey histologically by Fortuyn (1914). The publications of these authors provide a fairly comprehensive anatomical basis for the interpretation of Marchi sections.