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In a groundbreaking study published on November 22, 2024, researchers at Northwestern Medicine unveiled significant findings about the brain’s social cognition network, revealing that the DN-B network is intricately connected to the amygdala and the anterior regions of the medial temporal lobe (MTL).

This discovery opens new possibilities, less-invasive brain stimulation therapies for disorders related to social cognition, such as autism, schizophrenia, anxiety, and major depression.

The amygdala, long been recognized as a key player in emotional regulation and social behavior, is now better understood in the context of  specific neural networks within the medial temporal lobe (MTL).

The study demonstrated that the anterior MTL is more strongly connected to social cognition (DN-B), while the posterior regions of the MTL are more linked to episodic memory (DN-A).

Although DN-A and DN-B are closely interrelated within the MTL, they function independently.

Notably, DN-B is primarily located near the basolateral amygdala (Basolateral Amygdala, BLA), while DN-A does not show consistent connectivity to the amygdala.

The findings indicate that the amygdala-anterior prefrontal cortex circuit is part of a broader distributed associative network involved in social cognition, with DN-B uniquely and selectively connecting to the amygdala.

DN-B refers to one of two parallel distributed networks in the brain, forming part of the default network (DN), which governs social cognitive functions.

Specifically, DN-B is associated with regions of the brain that play a role in social cognition, such as theory of mind (ToM), which is the ability to think about others' thoughts and intentions.

Researchers also found that DN-B is located near the Basolateral Amygdala (BLA) and connects to multiple regions, including the frontal cortex, temporal pole, and anterior cingulate cortex.

Additionally, the DN-B also extends to the amygdala's internal circuits, including the medial amygdala (Medial Amygdala, MeA), which is crucial for instinctive social behavior and plays a significant role in human social cognition.

These findings emphasize the potential for new innovative treatments for social cognitive disorders.

Currently, deep brain stimulation (DBS) is used to address such conditions, but it requires invasive surgery due to the amygdala’s deep location in the brain.

During DBS, the patient generally remains awake while local anesthesia is administered to numb the scalp. 

The surgeon makes a small incision in the skull and inserts a thin electrode into the targeted brain region. 

For social cognitive disorders, the typical targets are deep brain structures such as the amygdala, prefrontal cortex, or other associated regions involved in emotion regulation and social behavior.

DBS. however,  typically carries risks such as infection, bleeding, or cognitive side effects due to its  invasive nature of the procedure.

However, the new study's findings suggest that a less-invasive method, such as transcranial magnetic stimulation (TMS), could target areas of the brain that are connected to the amygdala, offering a safer therapeutic alternative.

By identifying accessible cortical regions linked  to DN-B, this research opens  the possibility of modulating amygdala activity and improving treatment outcomes for conditions related to social cognition.

This breakthrough paves the way for  treating disorders such as  autism, schizophrenia, anxiety, and major depression using non-invasive techniques without carrying significant risks.