Why Is My Brain Always Talking? The Default Mode Network in ADHD, Autism, and AuDHD

By Tim Aiello, MA, LPC, NCC, ADHD CCSP, ASDCS

There is basically never silence in my head. I have an internal monologue that talks, thinks, analyzes, remembers, plans, questions, narrates what I am doing, and occasionally starts an entirely unrelated conversation while I am trying to focus on something else. Even when I am physically sitting still, my brain rarely feels still. There is almost always something happening in there.

For a long time, I assumed this was simply what thinking felt like. As I learned more about ADHD, autism, AuDHD, nervous system regulation, and eventually the default mode network, I started to understand that there may actually be some neuroscience behind why certain brains seem to produce such a relentless stream of internal activity.

To be clear, the default mode network is not literally the voice in your head, and having an active inner monologue does not mean something is wrong with your brain. The DMN is much more complicated than that. But research increasingly suggests that differences in how this network communicates with attention, executive, and salience networks may help explain why many people with ADHD, autism, and AuDHD experience their internal world as incredibly active, sometimes creative and comforting, sometimes exhausting, and often both at the same time.

So, What Exactly Is the Default Mode Network?

The default mode network, usually shortened to DMN, is a group of interconnected brain regions that become especially involved when attention turns inward. Instead of concentrating heavily on something happening outside of us, the brain begins processing memories, imagining the future, thinking about ourselves, interpreting social experiences, generating ideas, wandering between thoughts, and constructing the ongoing story of who we are.

Some of the major regions involved include the medial prefrontal cortex, posterior cingulate cortex, precuneus, angular gyrus, and parts of the temporal lobes. Rather than being one single structure, the DMN is better understood as a communication network connecting multiple parts of the brain.

Modern neuroscience has also moved away from the old idea that the DMN is simply the brain's resting network. Researcher Vinod Menon has argued that one of its broader functions may be creating something remarkably similar to an internal narrative. The DMN appears to integrate memory, language, emotion, meaning, and information about ourselves into the ongoing internal story we experience as thought. That makes the connection to the experience of an internal narrator particularly interesting, even though we cannot simply say that the DMN equals the inner monologue.

This network is not a malfunction. We need it. It helps us remember what happened yesterday, imagine what might happen tomorrow, reflect on relationships, understand ourselves, solve problems, daydream, create, and make meaning out of our experiences. Some of the most interesting parts of being human probably depend heavily on the DMN.

The problem appears to be less about having a default mode network and more about regulating when, how strongly, and in what context it becomes involved.

ADHD and the Brain That Keeps Wandering

This is where ADHD research gets really interesting. One of the more consistent findings involves differences in the relationship between the DMN and networks responsible for sustained attention and goal directed activity.

When we become absorbed in something requiring focused attention, several networks involved in executive control and attention become more engaged. These are sometimes loosely grouped under the term task positive networks. At the same time, activity within parts of the DMN generally decreases. The brain shifts resources away from internally generated thought and toward whatever needs our attention right now.

In ADHD, that separation appears to be less reliable.

Research has repeatedly found altered communication between the DMN and attention or executive networks in ADHD. Studies have found reduced segregation between networks responsible for internally focused thought and those responsible for externally focused attention, meaning the brain's internal conversation may continue competing for attention even while a person is trying to focus on something else.

A large 2023 analysis involving several major neuroimaging datasets found differences in communication between the DMN and task positive networks in people with ADHD. Importantly, the researchers also emphasized that these differences were statistically small. That matters because neuroscience findings describe patterns across groups, not a universal brain scan that identifies every individual with ADHD.

Still, the overall pattern fits remarkably well with what many ADHD adults describe.

You are reading something, but another thought appears. Then that thought connects to a memory. The memory reminds you of something you forgot to do. That reminds you of someone you need to text. Suddenly you are imagining a conversation that has not happened yet, while another part of your brain is still technically looking at the paragraph you were supposed to be reading.

Your attention did not disappear. It went somewhere.

ADHD May Be as Much About Mind Wandering as Attention

One of my favorite areas of ADHD research looks at excessive spontaneous mind wandering. Researchers Natali Bozhilova, Giorgia Michelini, Jonna Kuntsi, and Philip Asherson have proposed that excessive mind wandering may represent an important part of ADHD itself.

Their description is almost painfully relatable. ADHD mind wandering can involve constant mental activity with rapidly changing topics and inconsistent thought content. Instead of choosing to daydream about something, the brain spontaneously generates thoughts that compete with whatever we are trying to do.

Their model proposes that difficulty regulating the DMN, combined with altered communication between the DMN and executive control systems, may contribute to this spontaneous internal activity. In other words, ADHD may not simply involve difficulty paying attention to the outside world. It may also involve difficulty regulating the enormous amount of attention being generated inside the brain.

That distinction matters because ADHD is still too often described as an absence of attention. For many of us, there is no shortage of attention happening. There are fifteen things requesting it simultaneously.

Barkley, Inner Speech, and the Narrator in Your Head

Dr. Russell Barkley's work gives us another useful piece of this puzzle, although I want to be precise here. Barkley's major theories of ADHD are primarily theories of executive functioning and self regulation, not theories specifically about the default mode network.

Barkley has argued for decades that ADHD involves impairments in behavioral inhibition that affect several executive functions, including working memory, emotional and motivational regulation, and the internalization of speech. Internal speech is basically the ability to talk to ourselves mentally, using language to guide behavior, solve problems, organize actions, rehearse information, and regulate ourselves.

Barkley later described verbal working memory as a form of self speech, essentially talking to yourself using your mind's voice. By adulthood, much of this self directed activity becomes invisible because it happens internally rather than out loud.

This does not mean Barkley's internal speech model and the DMN are the same thing. They are not. But they describe overlapping parts of the subjective experience.

The DMN helps generate internally focused thought, autobiographical memory, imagination, meaning, and narrative. Executive systems help organize, inhibit, prioritize, and direct mental activity. If the relationship among these systems works differently in ADHD, it makes sense that the experience could feel like having an incredibly talkative brain without a particularly reliable volume knob.

The thoughts keep coming. The challenge is deciding which ones get the microphone.

Hallowell, Ratey, and the "Demon" of ADHD

Dr. Edward Hallowell and Dr. John Ratey discuss the DMN extensively in ADHD 2.0. They contrast the DMN with the task positive network and describe ADHD as involving difficulty transitioning cleanly between internally focused and externally focused states.

Hallowell has famously nicknamed the DMN the "demon" of ADHD because of its potential connection to distraction, negative internal dialogue, and rumination. The metaphor is memorable, although I think it needs a little context. The DMN is not inherently negative, and newer research makes clear that the relationship between internal and external attention networks is much more complex than one simply turning on while the other turns off.

Sometimes these networks cooperate. Creative thinking, planning, problem solving, and certain forms of mind wandering can involve both the DMN and executive networks working together. Research has even found simultaneous recruitment of default and executive networks during periods of mind wandering.

So I would not call the DMN the enemy.

For an ADHD brain, the problem may be that an incredibly useful internal network does not always respect office hours.

What About Autism?

This is where we have to resist making the science sound cleaner than it actually is.

Research absolutely shows differences involving the default mode network in autistic people. However, unlike some simplified explanations floating around online, the evidence does not show that autistic people universally have an "overactive DMN."

Studies have found both increased and decreased connectivity within different parts of the DMN in autism. Researchers have also found differences in communication between the DMN and other networks involved in attention, salience detection, social cognition, sensory processing, and executive functioning. These patterns appear to vary according to age, developmental stage, cognitive profile, and individual characteristics.

This makes sense when we remember how heterogeneous autism is. There is no single autistic brain, just as there is no single ADHD brain.

The DMN is particularly interesting in autism because it contributes to self related processing, autobiographical thinking, social interpretation, understanding other people's mental states, and integrating internal experiences. Research suggests that the organization and communication of the DMN can differ in autistic brains across several of these domains.

That does not automatically mean more thoughts. It means different network dynamics.

For some autistic adults, however, those differences may contribute to deeply immersive internal processing, replaying conversations, analyzing interactions, scripting future situations, connecting information, developing intense interests, repeatedly examining unresolved problems, or becoming caught inside thought loops. Other processes involving anxiety, sensory processing, executive functioning, and repetitive cognition can also contribute, so blaming everything on the DMN would be way too simplistic.

And Then There Is AuDHD

AuDHD makes this conversation even more interesting because ADHD and autism do not simply stack neatly on top of each other. The interaction seems to create its own complicated cognitive experience.

Unfortunately, direct DMN research specifically examining people with both autism and ADHD is still limited. A major review of DMN research in the two conditions specifically identified this as a weakness in the literature. Most neuroimaging studies historically separated participants into ADHD and autistic groups instead of seriously examining people who have both.

The studies that do exist suggest there may be shared differences in communication between the DMN and attention networks. A large 2025 analysis of more than 12,000 children and adolescents found increased connectivity between the default mode network and dorsal attention network in both autistic and ADHD groups compared with neurotypical participants. Again, the effects were subtle, but the overlap is fascinating.

Earlier research examining autistic children with co occurring ADHD symptoms also identified differences within the DMN and in its communication with other networks compared with autistic children without ADHD.

We still need much more adult AuDHD research before making sweeping conclusions. But the emerging picture fits something many AuDHD adults already recognize intuitively, the brain can be simultaneously internally busy, sensory aware, analytical, imaginative, distracted, detail oriented, emotionally reactive, and completely absorbed.

That is a lot of traffic for one nervous system.

Why My Brain Gets Quieter When My Nervous System Is Regulated

This part is especially interesting to me personally. I cannot completely turn off my internal monologue, and honestly, I am not sure I would want to. It is part of how I think.

What I can do is turn the volume down.

When my nervous system is regulated, the thoughts feel less aggressive. There is more space between them. I can notice a thought without immediately following it down three additional hallways. My internal narrator is still there, but it feels more like someone calmly sitting next to me instead of someone frantically flipping through forty television channels.

There is some neuroscience that supports this general experience, although I would be cautious about saying that nervous system regulation literally "shuts off" the DMN.

Mindfulness research has repeatedly found changes involving the DMN, executive networks, and salience networks. A recent review of network neuroscience and meditation found evidence that mindfulness training can reduce connectivity within portions of the DMN, although the literature is still developing and results vary depending on the type and duration of practice.

Breathing and autonomic regulation also influence large scale brain connectivity. Newer research examining paced breathing has found changes within central autonomic networks, reinforcing something therapists working from somatic and nervous system frameworks have recognized for a long time, changing what the body is doing can change what the brain is doing.

I would not claim that a long exhale, grounding exercise, cold water, stretching, rhythmic movement, or sensory regulation directly flips an "off switch" on the default mode network. Neuroscience is not that tidy.

What these strategies can do is alter arousal, redirect attention toward present sensory information, increase bodily awareness, engage executive and salience systems, and potentially reduce the amount of cognitive bandwidth available for uncontrolled internal wandering. Subjectively, that can feel like the brain finally getting quieter.

Rumination Is Not the Same Thing as Thinking

Another important distinction is that an active DMN is not automatically rumination.

The DMN helps us create, imagine, remember, plan, and reflect. Those things can be incredibly useful. The same brain that keeps you awake replaying an awkward conversation from six years ago might also connect two completely unrelated ideas and produce something genuinely creative.

Rumination appears to involve more specific patterns of repetitive self focused thought and altered communication between the DMN and networks responsible for cognitive control and salience detection. Reviews of neuroimaging research have repeatedly associated rumination with changes in DMN connectivity, particularly involving regions responsible for self related processing.

That distinction matters for neurodivergent people because we should not pathologize having a rich internal world.

Some minds are simply loud.

Some minds think in pictures, some in language, some in patterns, some through imagined conversations, and some through combinations of all of them. Neurodivergent cognition often involves enormous amounts of internally generated information.

The goal does not have to be making the brain silent. The goal can be having more control over when we listen.

Learning to Turn the Volume Down

For me, nervous system regulation has become less about trying to "stop thinking" and more about changing my relationship with the thoughts that are already happening.

Movement helps. Slow breathing helps. Sensory grounding helps. Music helps. Focused activities help. Connection with safe people helps. Sometimes deeply engaging work helps because my attention finally has something compelling enough to organize around.

This also explains why telling someone with ADHD or AuDHD to "just relax" can be hilariously ineffective. Removing external stimulation does not necessarily create quiet. Sometimes it simply gives the internal world the entire stage.

For some neurodivergent brains, regulation may actually require giving the nervous system the right kind of input instead of removing input altogether. Rhythmic movement, pressure, music, temperature changes, breathing, fidgets, repetitive movement, predictable sensory experiences, or meaningful focused activity can provide enough organization that the brain no longer has to generate quite so much competing noise.

Hallowell and Ratey talk about movement, connection, engagement, and finding the right kind of challenge as important parts of ADHD regulation. I think there is something deeply neuroaffirming about that perspective. Instead of demanding that an ADHD brain become quiet through force, we can create conditions that make regulation easier.

Maybe the Goal Was Never Silence

The more I learn about the default mode network, the less interested I am in completely turning it off.

That internal narrator is responsible for some annoying shit. It reminds me of things at terrible times. It rehearses conversations that will probably never happen. It occasionally starts reviewing my entire life while I am trying to fall asleep. It can pull my attention away from the present before I even realize I left.

But it also connects ideas. It reflects. It imagines. It creates meaning. It notices patterns. It allows me to think deeply about people, experiences, relationships, and the work I do.

The same internal world that can become overwhelming can also be incredibly rich.

For ADHD, autistic, and AuDHD adults, understanding the default mode network gives us another way to think about our experience without reducing it to "you are distracted" or "you think too much." There may be very real differences in how our brains move between internal thought, external attention, sensory information, executive control, and emotional states.

And maybe that is the better question.

Instead of asking, "How do I make my brain stop?"

Maybe we ask, "How do I help my brain know when it is time to listen, when it is time to wander, and when it is finally okay to be a little quieter?"

That feels much more realistic to me.

References

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Bozhilova, N. S., Michelini, G., Kuntsi, J., & Asherson, P. (2018). Mind wandering perspective on attention deficit hyperactivity disorder. Neuroscience & Biobehavioral Reviews, 92, 464 to 476.

Christoff, K., Gordon, A. M., Smallwood, J., Smith, R., & Schooler, J. W. (2009). Experience sampling during fMRI reveals default network and executive system contributions to mind wandering. Proceedings of the National Academy of Sciences, 106(21), 8719 to 8724.

Hallowell, E. M., & Ratey, J. J. (2021). ADHD 2.0: New Science and Essential Strategies for Thriving with Distraction, from Childhood through Adulthood. Ballantine Books.

Harikumar, A., Evans, D. W., Dougherty, C. C., Carpenter, K. L. H., & Michael, A. M. (2021). A review of the default mode network in autism spectrum disorders and attention deficit hyperactivity disorder. Brain Connectivity, 11(4), 253 to 263.

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