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The term [thalamus] arises from the Latin (Thalamo], meaning “the wedding chamber”, "the inner chamber" or “the wedding bed”. It also has a similar meaning in Greek. Early anatomists thought that the enclosure of the lateral ventricles with the fornix as a roof formed a chamber. The lager nuclear mass known as the thalamus looked to some as a double bed in a chamber, hence the name.
It did help that the thalamus has a larger posterior protuberance akin to a cushion or a pillow, the pulvinar.
The thalamus is a paramedian structure which forms the lateral walls of the third ventricle of the brain, as well as part of the floor of the lateral ventricles of the brain. It can sometimes (30%) present a midline mass which communicates both thalami across the third ventricle. It is separated from the mesencephalon (midbrain) by the subthalamic region.
It is an important relay system, as all the sensory information to the brain (with the exception of the olfactory) has a synaptic stop at one or more of the thalamic nuclei before being sent to the cortex of the brain. The thalamus also receives important motor collaterals, as well as cerebellar and subthalamic information. This makes the thalamus an important entity in the regulation of fine motor control. Thalamic dysfunction can lead to sleep disorders and coma.
The thalamus also serves as an important relay between sensory, motor, limbic, and hypothalamic activity, making it critical to the relation of emotions, visceral responses, and prefrontal cortical activity. It also plays an important role in wakefulness, and consciousness.
In the accompanying image the thalamus is found covered by the choroid plexuses of the lateral ventricle.
Note: The links to Google Translate include an icon that will allow you to hear the pronunciation of the word. Image property of CAA, Inc. Photographer: E. Klein