<prompt> Thyroid hormone receptor which is predominantly expressed in CNSBrain ?a - 1a - 2b-1b-2  <response>: Ans. isci.e., b-1There are three forms of thyroid hormone receptor that are able to bind thyroid hormone.TR - alpha 1 Widely expressed with high expression in cardiac and skeletal muscle.TR- beta 1- Predominantly expressed in brain, liver and kidney.TR- beta 2- Expression primarily limited to hypothalamus pituitary.Fouh isotypes TR- alpha2, is also widely expressed but is unable to bind thyroid hormone. 