Summary
This brain structure is the switching station between sensory input and further processing in the brain. It is located in the center of the brain. Smell is the only sense for which information does not need to go to the thalamus before it can be processed. Damage to this area can lead to Dejerine-Roussy syndrome.

Function
This structure has many different functions, but they can generally be summarized as the “switching station”. The thalamus transmits information from the autonomic nervous system to the central nervous system and vice versa. Different sensory stimuli pass through the thalamus before further processing takes place in the brain.

In our environment and our body there are so many different sensations that it is impossible to process them all. Therefore, the thalamus examines what is important or what your attention is focused on. This information is then sent to the cortex, or stored in  memory.

Location
The thalamus, together with the hypothalamus and pituitary gland, forms the diencephalon. The thalamus is located at the top of the brainstem, near the center of the brain. From the thalamus, neurons project to all parts of the cerebral cortex.

Fact
Smell is the only sense whose signals are not filtered by the thalamus. These signals are processed immediately when they enter the brain. This is probably because smells can give off signals that are important for survival. This is for example the case when you smell fire, the fast processing enables you to react quickly.

Patients
A stroke can cause damage to the thalamus, leading to Dejerine-Roussy syndrome. Patients suffer from tingling sensations, ranging from annoying to very painful. It can also happen that patients experience certain stimuli as painful that healthy people do not. One example is the blowing of air against the arm.

Severe vitamin B1 deficiency can also cause damage to the thalamus. This type of damage is often associated with Korsakov's syndrome. This is a disorder that causes a lot of memory problems, but also disorientation. In addition, patients with Korsakov's syndrome often have little empathy, and take little or no account of other people's feelings.

Author: Myrthe Princen (translated by Pauline van Gils)

Image: Marcel Loeffen