Thyroid Hypofunction and the Development of the Central Nervous System

METHYL thiouracil depresses the thyroid, and the brains of rats made cretinous with this drug grow proportionately less in length than they do in width or height 1 . Further results of this treatment are that myelination is retarded 2 and that the pyramidal cells of the lamina ganglionaris of the sensori-motor cortex-are smaller and more closely packed than in normal animals 1 . The spaces between the cell bodies are occupied for the most part by neuroglia, blood vessels, axons and dendrites, and an attempt to find an explanation for the closer aggregation of the cell bodies in cretins has been made by analysing the rate of growth of each of these components.