Intercalated nucleus

Intercalated nucleus is a small collection of neurons found in the amygdala of the brain. It is a part of the limbic system, which is involved in emotion processing, learning, and memory. The intercalated nucleus plays a crucial role in fear conditioning and extinction, which are essential for survival and adaptation.

Structure

The intercalated nucleus is composed of small clusters of GABAergic neurons. These neurons are inhibitory, meaning they reduce the activity of other neurons. They are located between the basolateral and central nuclei of the amygdala, hence the name "intercalated".

Function

The primary function of the intercalated nucleus is to regulate the activity of the amygdala. It does this by inhibiting the output of the central nucleus, which is the main output nucleus of the amygdala. This inhibition is crucial for the extinction of conditioned fear responses.

In fear conditioning, a neutral stimulus (such as a tone) is paired with an aversive stimulus (such as a shock). After repeated pairings, the neutral stimulus alone can elicit a fear response. The intercalated nucleus is involved in the extinction of this conditioned fear response. When the neutral stimulus is presented without the aversive stimulus, the fear response gradually decreases. This process is known as extinction.

Clinical significance

Alterations in the function of the intercalated nucleus have been implicated in anxiety disorders, such as post-traumatic stress disorder (PTSD) and phobias. In these disorders, the extinction of fear responses is impaired. This may be due to changes in the activity of the intercalated nucleus or its connections with other brain regions.

See also

• Amygdala
• Fear conditioning
• Extinction (psychology)