Purpose—the meaning you assign to your existence—is the central question of your life.

It is your north star; the highest good that you can imagine. It is responsible for your greatest triumphs and your proudest moments. It is a legacy that will affect many whose paths intersect your own: your children, family and friends, significant others, co-workers, employees, students, clients, audience.

A sense of purpose makes it more likely you will experience a full, satisfying life of well-being; successfully weather life’s continuous challenges; help others find their way.

I have written extensively on the mental, physical, emotional, spiritual and social aspects of purpose. In this essay, I am happy to introduce you to something that lives in your head and interacts with your sense of purpose: The default mode network (DMN for short).

What the DMN Does

The default mode network is a complex collection of interacting brain regions that is responsible for a great deal of our internally-generated thought. This network is a major contributor to the “voice in your head” in many ways. It influences memories of experiences you have had, thinking about yourself and others, thinking about thinking (metacognition), even constructing your mental image of who and what you are.

Especially important to our discussion about purpose, the DMN is instrumental in your visualization of your future.

If you regularly make a long commute, the DMN is a familiar companion.

You are driving down the freeway at 65 miles per hour, watching the traffic and the road ahead. Your mind—your attention—is (hopefully) actively engaged in this potentially dangerous activity.

But on those longer stretches of the Interstate, there is another train of thought.

You may be replaying a conversation with a co-worker; mentally organizing tomorrow’s tasks; planning dinner; anticipating the evening’s activities.

The default mode network is called “default” because it is the network of brain areas that have decreased activity when you are intensely focused on some external task. It is the baseline—the default—that your brain returns to between demanding tasks in the real world.

This doesn’t mean you aren’t thinking; it means your attention is focused on something in your head (planning a difficult conversation or imagining your next painting) as opposed to something in your environment (building a treehouse or preparing to jump out of a plane to skydive).

Where the DMN Is Located

The default mode network is a collection of interconnected areas in your brain—a literal network. There is no single location at work.

Like all brain topology, the terms used to describe the various regions involved in the DMN have long, scientific-sounding names, but really just identify where they are.
Here are a few of the brain locations at play in your inner world, as we currently understand them:

- Medial prefrontal cortex: the inside regions of the frontal lobes of your brain. This area is concerned with your ideas about yourself.

- Posterior cingulate cortex and adjacent precuneus: These hubs of information processing help you integrate your internally-directed thoughts; they are located at the back and inside of your brain.

- Angular gyrus and other inferior parietal areas: These are areas on the sides of your brain toward the bottom, that integrate memories and concepts.

- Lateral temporal regions: These areas on the sides of your brain near your ears work with information about people, and concepts about the world.

- Hippocampus and other medial temporal regions: buried inside the brain lobes near your ears, these areas are heavily involved with the formation and processing of memories, and your ability to imagine experiences that you have not actually experienced.

There will be no quiz (unless you are taking my class on physiological psychology, then all bets are off): I list these areas to show you that the DMN is made up of areas that are scattered across different parts of your brain, and that talk to each other through a complex network of pathways.

All of these areas have many other functions as well, and none of them are solely responsible for your internal mental world by themselves.

Together, they enable you to evaluate information for its personal relevance, the way you understand and act within social systems, the way you perceive and use your memories, and—as pointed out earlier, in reference to your chosen purpose—allow you to ponder and mentally simulate your future.

You may be wondering how we have learned all this. After all, we have to study these processes while the person is alive and thinking; we can’t pull a brain out and look at it under a microscope to see how it is functioning.

There are many recent and exciting (if you are into this stuff) ways that we can watch the brain work in real time. One of the most frequently-used and proven is functional magnetic resonance imaging, or fMRI. You have probably heard of, or perhaps have experienced an MRI; the functional part means we can watch your brain as it works, to see which areas are involved.

The research also frequently mentions large chunks of other interconnected areas:

- The frontoparietal control network, along the sides of the front of your brain, helps maintain goals and organize your thoughts.

- The salience network (salience means something is important to you), found in areas toward the front of your brain, marks events as important, and helps you shift between internal and external focus of thought.

The DMN and Monkey Mind

You may have heard the term “monkey mind” (no offense to primates). It is a metaphor that describes your mind when it is unfocused, jumping from event to event, from concept to concept. The idea is that you are not controlling the focus of your thoughts and are instead letting them “run wild.”

Buddhist teaching uses the concept to describe thoughts that come through your consciousness and should then be allowed to pass through—and out of—your mind so that you can concentrate on something of more importance.

We have all experienced monkey mind; in fact, as we have ever-more distractions and a decreasing attention span, many live here the majority of their waking time:

Why haven’t they responded to my text? I sounded like an idiot in that meeting. Did I do something to make them angry? Is this relationship over? Is it time for an oil change? I don’t want to cook dinner tonight.

If you have been following along, you can guess what functional brain area is involved in this kind of scattered thought: the default mode network.

The DMN, as we have said, contributes to self-reference, autobiographical memory, future simulation and more, all parts of these untamed mental images.

Wandering thought, while not particularly productive in many cases, is relatively harmless. It becomes problematic when distressing thoughts start to loop.
This process is called rumination, and it can cause worry and anxiety. You can replay the same concerning thought over and over and become “stuck” in the loop.

Monkey mind—the wandering thoughts of your unfocused mind—has been associated with decreased happiness. This doesn’t mean that the DMN caused the unhappiness, but now that you understand that letting your thoughts roam freely can result in less than optimal use of your brain, you can choose to focus on something specific when you are feeling “down.”

And what better subject of your controlled focus than the future you would like to have?

Purpose as Focus

Purpose—the meaning you assign to your existence—is not something that is delivered from some vague celestial source, in most cases.

You have the wonderful and frankly amazing ability to choose what you want your life to be about. And you have the inalienable right to change that purpose as your circumstances dictate.

There are two parts to purpose: the thought and the action.

Let’s imagine an example of how all this fits together:

You have been having more anxiety than usual, as of late. You remember this essay saying something about monkey mind and rumination and worry, so you stop to evaluate your recent life.

And you realize that you have been spending a lot of time worrying about your co-worker who is becoming increasingly problematic.

In fact, it feels like you can’t stop thinking about the situation: what you should have said, what you are going to say next time, how that might make you look to the boss, whether you are going to get the next promotion.

To stop the anxious thoughts, you have been doomscrolling, staying up too late, and engaging in other less-than-healthy practices that help keep you from worrying about scary future possibilities.

And now you know that these loops and internal thoughts are involved with different, connected parts of your brain called the DMN.

The answer, you remember, is to corral those thoughts, get them under control and focus them on something positive.

Not just happy thoughts, but a goal with specific actions that will help you change your situation in the real world, not just in your mind.

Maybe you see that the problem isn’t just your co-worker; it’s the whole dead-end job that you have stayed in because it is convenient. It seemed easier to stay than to start over, but now you realize that dealing with the situation is anything but easy, and it’s not getting better.

So you choose to change it up.

You spend time in directed, concentrated thought about where you want to end up next. The time that used to be spent doomscrolling social media is now spent writing down the way you want your world to be. TV bingeing gives way to researching what it will take to actually change, to move towards your new goal.

Then comes the hardest—and most rewarding—part.

Purpose as Action

You choose to do what you need to do.

You have decided on a new direction. You have learned what it will take to go there.

All that remains is to take the required action.

Like so many things about human life, it’s simple but not easy.

The new job in the new city that will be fulfilling and meaningful and pay better and help people is the goal. But you need additional education.

So you learn what education is involved and where you can obtain it.

Now you go enroll and start taking the classes.

Action is what will help you focus to stop the rumination and decrease the anxiety.

Action is what changes your thoughts from “I hate this” to “I’m changing this.”

Action is the only road you can take to make the purpose in your mind become the new life you envisioned in the real world.

This is just an example; if you want to be a nurse you have to go take nursing classes.

But there are many purposes; many paths.

Maybe you are a nurse, but you want to become a rancher.

You have had your fill of banking and now you want to sell oceanside real estate.

In every case, your chosen vision of purpose breaks the “stuck.”

It is your action that brings purpose into physical reality, and changes your life.

Your DMN is still there, still functioning. But now it is focused on imagining your desired future, not ruminating about your unpleasant present and irretrievable past.

Here’s the framework:

Choose something that matters. Ideally, this will include a purpose bigger than yourself, to sustain you when the going gets rough.

Get your DMN onboard by focusing on imagining your awesome new future.
Write out your plan in terms of doable steps (fire up that frontoparietal control network!)

ACT. Take the steps you outlined, evaluate the results, make course corrections if necessary, and keep moving forward.

Celebrate the wins. Each course passed, client signed, widget created, article read. Take time to say, I’m doing it!

Revel in the fact that your thoughts—and your DMN—are now forces for good.

Besides, you’ll be too busy moving your life forward to be concerned about anything else.

References

Abellaneda-Pérez, K., Cattaneo, G., Cabello-Toscano, M., Solana-Sánchez, J., Mulet-Pons, L., Vaqué-Alcázar, L., Perellón-Alfonso, R., Solé-Padullés, C., Bargalló, N., Tormos, J. M., Pascual-Leone, A., & Bartrés-Faz, D. (2023). Purpose in life promotes resilience to age-related brain burden in middle-aged adults. Alzheimer’s Research & Therapy, 15, Article 49. https://doi.org/10.1186/s13195-023-01198-6

Basso, J. C., McHale, A., Ende, V., Oberlin, D. J., & Suzuki, W. A. (2019). Brief, daily meditation enhances attention, memory, mood, and emotional regulation in non-experienced meditators. Behavioural Brain Research, 356, 208–220. https://doi.org/10.1016/j.bbr.2018.08.023

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Huberman, A. (Host). (2022b, November 14). Science-based tools for increasing happiness [Audio podcast episode]. In Huberman Lab. https://www.hubermanlab.com/episode/science-based-tools-for-increasing-happiness

Huberman, A. (Host). (2026, March 16). Science-based meditation tools to improve your brain & health | Dr. Richard Davidson [Audio podcast episode]. In Huberman Lab. https://www.hubermanlab.com/episode/science-based-meditation-tools-to-improve-your-brain-and-health-richard-davidson

Jing, H. G., Madore, K. P., & Schacter, D. L. (2016). Worrying about the future: An episodic specificity induction impacts problem solving, reappraisal, and well-being. Journal of Experimental Psychology: General, 145(4), 402–418. https://doi.org/10.1037/xge0000142

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Sridharan, D., Levitin, D. J., & Menon, V. (2008). A critical role for the right fronto-insular cortex in switching between central-executive and default-mode networks. Proceedings of the National Academy of Sciences, 105(34), 12569–12574. https://doi.org/10.1073/pnas.0800005105



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