Have you ever wondered why one random thought disappears instantly while another keeps following you all day?

“Did I send that email?”

“What if I left the stove on?”

The difference isn’t the thought itself. It’s what the brain decides to do with it.

The Brain Can’t Process Everything

Every second, our brains receive far more information than they can possibly process.. They need a filter to distinguish what matters most.

Meet the Salience Network

A brain network called the Salience Network takes on this task. 

A brain network is simply a group of brain regions that work together to perform a specific function.

The Salience Network is a network that helps identify which information deserves attention.

Think of it as the brain’s importance detector.

Two key regions in this network are the anterior insula and the anterior cingulate cortex (ACC).

Anterior insula constantly scans both the environment and the body for potentially important information while ACC helps decide whether that information deserves attention and action.

Remember the Default Mode Network…

Remember that the Default Mode Network constantly produces thoughts, memories, images…

The Salience Network acts as a switch between the Default Mode Network and the Frontoparietal Network, helping direct our attention toward a specific thought.

Without such a system, every thought would compete equally for our attention.

When the System Goes Awry

What happens when the brain mistakenly flags something as important?

We’ll explore this in our next post.

Want to read the science behind this?

Vinod Menon, & Lucina Q. Uddin (2010). Saliency, switching, attention and control: a network model of insula function. Brain Structure and Function, 214(5–6), 655–667.

Vinod Menon (2011). Large-scale brain networks and psychopathology: A unifying triple network model. Trends in Cognitive Sciences, 15(10), 483–506.