impact of thyroid hormones on brain development

Thyroid hormones (THs) including triiodothyronine (T3) and tetraiodothyronine (T4) perform an essential role in brain development. The active form (T3) of THs is produced after metabolism and transported in different areas of brain. This actve form  acts either by interacting with different types of glial cells or by mediating the expression of various genes for producing typical growth proteins. These protiens control many brain developmental processes such as synaptogenesis, neurogenesis, cell proliferation, differentiation, migration and maturation. During pregnancy the inadequate intake of iodine (I2) by pregnant mothers is associated with clinical manifestations because early brain development is totally dependent upon THs coming from maternal origin. A reduction in THs can alter these specific brain developmental processes, thereby changing the cognitive performance. On other hand THs supplementation can recover the normal circumstances