Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The subthalamus is a part of the diencephalon. During development the subthalamus is continuous with the hypothalamus, but is separated by white matter fibres mainly from the internal capsule. Caudally, the subthalamus or prethalamus is separated from the thalamus by the zona limitans intrathalamica. Other nuclei of the subthalamus are the zona incerta, thalamic reticular nucleus, and the fields of Forel. Post-natally the subthalamus lies beneath the thalamus, hence ''sub'' (meaning below) ''thalamus''. It also lies dorsolateral to the hypothalamus.
