Why Some Thoughts Just Won’t Leave: The Neuroscience of “Sticky” Thoughts

In our previous article, we explored why some thoughts become more salient than others.

In this article, we will explore why some thoughts just won’t leave.

How The Brain Normally Focuses On One Thought After Another

Attention is supposed to be temporary.

The brain is supposed to attend to specific information for a certain period and then shift its focus as necessary.

Cortico-striato-thalamo-cortical circuit (CSTC)  is known to be involved in this.

Orbitofrontal cortex, striatum, thalamus, and other cortical regions are the main players of this circuit.

Normally, when a problem is detected by the orbitofrontal cortex (OFC), the brain wants to do something in order to solve it. The striatum initiates appropriate behavior while the thalamus sends this information to the cortex. Then, the cortex can reevaluate if the problem has been resolved.

These processes happen rapidly and continuously rather than one after another.

When the Case Just Can’t Be Closed

In some situations, the brain can’t be sure whether the problem has been solved. As a result, the case can’t be closed.

For example, when someone has the thought: “Did I leave the stove on?”, orbitofrontal cortex takes this as a problem: “I may not have checked the stove.” 

Then, the striatum initiates the behavior, which is checking the stove.

The thalamus sends this information to the cortex that the stove is checked.

The cortex then reevaluates whether the problem has been resolved. 

What Happens in Obsessive-Compulsive Disorder?

In obsessive-compulsive disorder (OCD), the brain just can’t get the feeling of being sure and restarts the loop, “Did I leave the stove on? Maybe, I didn’t check it.”

One possible explanation is that the brain may fail to generate a strong sense that the task is complete.

But, how does the brain normally know that a task is finished?

The anterior cingulate cortex (ACC), which is known to be involved in error monitoring, may play a role here.

Normally, as the brain no longer detects a potential problem, attention can shift elsewhere.

In OCD, attention may fail to move on to the next thought because ACC may continue generating an error signal that the task is still incomplete.

The problem may not be that the brain never received the information that the task is finished, for example, that the stove has already been checked. It may be that the “something is still wrong” signal never fully disappears.

As long as that signal remains, the brain keeps treating the thought as an unfinished task.

What To Do When We Get Stuck in a Loop?

When we check the stove for the tenth time, it may be because the brain keeps signaling an “error” that the task is still incomplete.

When we go check it one more time, the importance of that error signal might be strengthened.

The brain learns that uncertainty requires another check. In fact, uncertainty doesn’t always signal a problem and brain can learn not to respond to it.

This is one of the core ideas behind Exposure and Response Prevention (ERP), the most effective psychological treatment for OCD.

And what makes the brain behave this way?

The answer may lie in tiny molecules called neurotransmitters that constantly change how brain cells communicate.

We’ll explore that in a future article.

See you in the next post,

Ayşegül Karadeniz

Want to Read the Science Behind This?

Networks and Attention

Menon V. (2011). Saliency, switching, attention and control: A network model of insula function.

OCD Circuits

Huey ED et al. (2008). A Psychological and Neuroanatomical Model of Obsessive-Compulsive Disorder.

Feeling of Completion

Gillan CM et al. (2011). When Too Much Is Not Enough: OCD as a Pathology of Stopping, Rather than Starting.