Thalamus

Abstract

The thalamus, also called the dorsal thalamus, is a large paired egg-shaped mass of nuclei located in the diencephalon (Figs. 23.1–23.3). It is bounded by the: interventricular foramen, rostrally; transverse cerebral fissure, dorsally; hypothalamic sulcus, ventrally; and posterior commissure, at the midline posteriorly (Figs. 1.5 and 5.1). Lateral to the midline, it extends further back to overlap the midbrain (Fig. 13.15). Thalamic nuclei process, integrate and relay information for the sensory, motor, limbic, and motivational systems. Some play a critical role in sensation and motor control. Thalamic nuclei also appear important for transferring information from one part of the cerebral cortex to another. The thalamus is so strongly interrelated with the cerebral cortex that in some senses it can be regarded as the deepest layer of the cortex (Sherman and Guillery 2001). Activity of thalamic nuclei is regulated by input from: ascending and related pathways, the cerebral cortex and the thalamic reticular nucleus.