Rewire Your Anxious Brain

Last updated: 2020-10-21

Rewire Your Anxious Brain

Author: Catherine Pittman and Elizabeth Karle

Who should read: Insomniacs, Worry warts, Meditators, Neuroscientist wannabes, Overwhelmed humans

Rating: 7 / 10

Over the years, I've been plagued by poor sleep. Some of it is probably due to my use of digital devices mere seconds before going to bed. Insufficient sunlight is probably another culprit. But I believe the main cause is anxiety.

I opened this book hoping to find answers.

While the book was a bit verbose and I wish it were better organized, I got a lot of value out of reading it.

In this summary, I try to distill my main takeaways. I've organized my summary into the following sections:

  1. The Biology of Anxiety
  2. Diagnosis
  3. Treatment

The Biology of Anxiety

The biology of anxiety can be understood as being comprised of two flows of information. The first flow originates in the amygdala, and the second in the cerebral cortex.

Throughout the book, the authors refer to these two triggers as "amygdala based anxiety" (which is typically based on real world events) and "cortex based anxiety" (which is typically based on thinking and cognition).

Here's an excellent diagram from the book that breaks down the flows of anxiety:

Two pathways of anxiety

The amygdala pathway is the one that goes: Real World Stimulus -> Thalamus -> Amygdala -> Anxiety Response

The cortex pathway is the one that goes: Cortex -> Amygdala -> Anxiety Response. The cortex pathway may or may not be triggered by real world events.

Notes on the Amygdala

Because all anxiety flows through the amygdala, it's useful to understand some special attributes of the amygdala that contribute to anxiety. Let's focus on three such attributes.

The first is that the amygdala has special direct connections to the hypothalamus, which in turn releases the hormones cortisol and adrenaline to generate the fight or flight response. This direct connection allows the amygdala to respond extremely quickly to stimulus. In fact, the amygdala can trigger this before the cortex realizes what's happening:

the amygdala receives information before the information can be processed by the various lobes in the cortex. This means the lateral nucleus of the amygdala can react to protect you from danger before your cortex even knows what the danger is. (p. 21)

The second is that the amygdala has the ability to form emotional memories. Unlike regular memories, these "memories" are scoped only to the amygdala and are inaccessible to our conscious minds. This means the amygdala may trigger an anxiety response for reasons you cannot rationalize.

The existence of different memory systems explains why you can experience anxiety in a situation without any conscious memory (or understanding) of why the situation produces anxiety. (p. 32).

These emotional memories form by associating sensory input with highly charged emotional events. Whatever sensory input your amygdala was processing right before a negative event will likely become an anxiety trigger.

And the third thing is that the amygdala can actually influence our thoughts a great deal.

There are many connections from the amygdala to the cortex, allowing the amygdala to strongly influence the cortex’s responding on a variety of levels, while fewer connections travel from the cortex to the amygdala (LeDoux and Schiller 2009). (p. 25)

Notes on the Cortex

When it comes to the cortex, the biology is much more complex, so I wont even attempt to outline it here.

With respect to anxiety, cortex based anxiety is much more familiar to us - it's what we traditionally think of when it comes to therapy.

The authors of the book simplify cortex based anxiety largely to our faculties of interpretation and anticipation:

when we speak of the cortex pathway to anxiety, we’re generally focused on interpretations, images, and worries that the cortex creates, or on anticipatory thoughts that create anxiety when no danger is present. (p. 20).

So all of those negative thoughts and images that lead to worry or the imagination of undesirable possibilities? That's the cortex. These thoughts generated by the cortex may be so powerful, we might start confusing them for reality, a phenomenon called cognitive fusion

cognitive fusion occurs when we get so caught up in our thoughts that we forget they’re merely thoughts. (p. 179).

Cognitive fusion and other negative patterns of thought can actually trigger anxiety, or exacerbate an already anxious amygdala.

Because both the cortex and amygdala can exacerbate anxiety triggered by the other, it is useful to familiarize yourself with techniques to calm both pathways, regardless of "who started it".


The book spends a great deal of time presenting a series of questions to help you determine if you have amygdala based anxiety or cortex based anxiety (or both).

While the detailed questions are presumably useful for the long tail of anxiety cases, I think the 80/20 rule applies here.

Early in the book, the authors provide these heuristics:

Cortex based:

If you find that your thoughts keep turning to ideas or images that increase your anxiety, or that you obsess over doubts, become preoccupied with worries, or get stuck in trying to think of solutions to problems, you’re probably experiencing cortex-based anxiety.

Amygdala based:

If you feel like your anxiety has no apparent cause and doesn’t make logical sense, you’re usually experiencing the effects of anxiety arising from the amygdala pathway.

You probably know which one you have more of. For me, I presume it's mostly cortex based anxiety, and some small degree of amygdala based anxiety.

I would hazard a guess that most people have a blend of these forms of anxiety as well, and we all need a strategy to manage both.

Thankfully, the book provides ample treatment ideas.


Given that there are two sources of anxiety, if follows that there are two different forms of treatment for each.

Let's first start with how we can settle the amygdala, and then understand how we can calm the cortex.

Treatment for Amygdala based Anxiety

Exposure Therapy

The best treatment for amygdala based anxiety solves for the root cause.

Recall that the amygdala forms emotional memories. If, for example, you were bitten by a dog as a child, your amygdala may associate the sound of barking with a highly negative event. Barking, whether that's from a dog in real life or just an audio clip, will trigger anxiety.

If you consistently avoid dogs the moment you hear them, you may be reinforcing your amygdala that the right thing to do is to flee. Over time, your amygdala will have learned that barking should lead to anxiety, which will lead you to flee, and thus "solve" the problem.

How can we fix this? Well, the authors mention there's only one way:

when it comes to amygdala-based anxiety, there’s only one sure way for the amygdala to learn: experience. (p. 49).

In other words, we must face our fears.

Therapists often employ a practice called "exposure therapy" for their clients and it generally comes in one of two forms: systemic desensitization (gradual) or flooding (diving into the deep end).

Systemic desensitization:

Systematic desensitization involves learning relaxation strategies and approaching feared objects or situations in a gradual manner. (p. 127).


With flooding, in contrast, people jump right in with the most fear-provoking situation, and the exposure may last for hours. (p. 127).

Which one works better?

Flooding may be more effective

Research indicates that intense, extended exposure to triggers that produce fear (flooding) is more rapid and effective than a gradual approach (Cain, Blouin, and Barad 2003). (p. 127)

But it is important to note that you have to see it through and experience anxiety for potentially hours. If you don't, it can backfire:

it’s possible to actually strengthen anxiety if you leave the exposure situation before your anxiety decreases. (p. 132)

One technique you may wish to employ is to create an "exposure hierarchy". As the name suggests, you create a list of situations that give you anxiety, from least to most. And then you start tackling the least scary ones first. For example, if you have a fear of driving, and in particular on the highway, your list might be:

  • Turning the car on
  • Backing out of the driveway and driving around the block with a friend
  • Same as above, but solo
  • Driving on local roads with a friend, for 10 minutes
  • Same as above, but solo
  • Driving on highways at night (low traffic) with a friend
  • Driving on highways during the day (medium traffic) with a friend
  • Practicing lane changes on the highway with a friend
  • Doing the above highway exercises solo

Give each of these a rating of anxiety level from 1 to 100.

Everyone will have different items that trigger more anxiety. For example, for two people who both get anxious driving on the highway, one might be anxious about the speed. Another may be anxious driving on the road by themselves.

The book recommends some particularly useful self talk. When you're about to do something that activates your anxiety, keep the following messages in mind:

  • "I expect my fear to rise, but I can manage it"
  • "I'm activating my fear circuits to change them. I'm taking control"

Facing your fears is the only way to address amygdala based anxiety in the long run. There is no other way to retrain your amygdala.

Ned Stark on Fear


While exercise will not solve amygdala based anxiety, aerobic activity will dampen the activation of the amygdala. Given that all anxiety, even anxiety that originates from the cortex, must pass through the amygdala - exercise is important for anyone who wants a calmer brain.

The short term effects of exercise can last for many hours:

exercise results in decreased muscle tension for at least an hour and a half afterward, and reductions in anxiety last from four to six hours (Crocker and Grozelle 1991). (p. 145)

Over the long run, it has a particularly calming effect on the amygdala:

Exercise appears to affect a certain type of serotonin receptor that’s found in large numbers in the lateral nucleus of the amygdala (Greenwood et al. 2012). Regular exercise seems to make these receptors less active, resulting in a calmer amygdala that’s less likely to create an anxiety response (Heisler et al. 2007). (p. 147)

The effects of exercise on your brain are far reaching and not just limited to anxiety and the amygdala - it's one of the best things you can do, not just for your muscles, but for your mind.


Try this: Take a deep breath. Watch your chest expand slowly. And now let go.

Did you feel the slightest sensation of relaxation? Didn't work? Try it again but slower.

Slow, deep breathing can help to bring down your heart rate and calm your amygdala. It works to counter your amygdala's fight or flight activation.

A more advanced form of breathing that is known as diaphragmatic breathing, which are colloquially referred to as "belly breaths". They're known to have an even stronger physiological calming effect on your body.

Other Relaxation Techniques

The book also mentions a few useful relaxation techniques. I personally don't use them very often, hence I won't dive much into them, but they're known to be useful for many people:

  • Progressive Muscle Relaxation
  • Relaxing Imagery - visualize a calming scene. The more details (objects, textures) and senses engaged (not just visual, but sound, touch, taste) the better

Treatment for Cortex-based Anxiety


Much of the anxiety that emerges from the cortex is problematic because we begin to confuse thoughts for reality. This grants negative thoughts extreme power, to the point of activating our amygdala.

In order to combat this, the book recommends adopting a meditation practice, with a goal of becoming the observer of your mind.

You’re an observer of your cortex, not a believer of everything it produces. (p. 183)

And here's a particularly neuroscientific take on observing the monkey mind:

To help distance yourself from a thought, you could tell yourself something like, “I need to be careful of this pesky thought. I have no reason to put faith in it, and it’s likely to activate my amygdala.” (p. 183)

You can start with a simple breath counting meditation:

  • Breathe in and out slowly, watching your belly rise and fall with each breath
  • With your attention focused on your belly, start counting the in-breath - "One"
  • And on each exhale, continue to count - "Two"
  • And so on
  • When you reach 10, restart
  • If your mind wanders (and it will!) simply start over on the next in-breath at "One"

The goal here is not to reach 10, the goal here is actually to catch your mind wandering and being distracted. Each time it becomes distracted and you gain awareness, this is the "work" of meditation. Stay focused on your breath for as long as you can, but it's almost inevitable you will become distracted. That's okay!

The benefits to meditation are myriad, and not only does it help to rewire your cortex, it has a calming effect on the amygdala too. So learning to become the observer of your own thoughts and feelings is one of the most effective practices you can adopt for managing anxiety.

Replacing Thoughts

One failure mode for many people who practice meditation is that they get angry when their mind wanders. Sometimes their mind may find a way to focus on negative thoughts or random thoughts again.

And during meditation, we simply regather our focus on whatever we want, whether that's our breath, or a mantra, and move forward.

Once you are outside of the confines of a meditation practice, negative thoughts may still emerge and they can begin to trigger anxiety. The book has a very interesting idea:

“Don’t erase—replace!” is the best approach with anxiety-igniting thoughts. (p. 187)

The idea here is simple, instead of trying to eliminate bad thoughts, distract yourself when you notice you're having a negative though pattern. If you can, be a positive framing on a negative situation "This might be tough, but I can chip away", or potentially just finding some absurdity in the situation.

Take this tweet for example:

You can find replacements for negative thoughts in resilience, humor, absurdity, optimism - anything. But the idea here: you can knock down a load bearing wall, but just make sure you put something else in it's place.

As the authors say:

Cultivating a sense of playfulness is essential... Playing games, joking, and engaging in silliness are some of the best distractions (p. 189)


For many of us, when confronted with a large or nebulous challenge, we might spend a lot of time worrying. But worrying is particularly dangerous when it comes to anxiety:

Researchers have shown that when people continue to think about a negative event, they lengthen their emotional reaction to the event, maintaining negative emotions for longer than they otherwise would have lasted (Verduyn, Van Mechelen, and Tuerlinckx 2011). (p. 190)

The antidote to worrying is to plan, or what I call metawork - or the work of clarifying and derisking your tasks - before execution begins.

In my own experience, there is an interesting connection between self esteem, productivity, planning, and worrying. If you focus on worrying, productivity and self esteem seem to fall. If you focus on planning or doing "metawork", productivity and self esteem often rise.

So short circuit worrying and plan. The moment you see yourself ruminating, grab a writing device and figure out a plan.


Overall, I found "Rewire Your Anxious Brain" to be a useful book in my understanding of anxiety. Perhaps because I know so little about neuroscience, I truly found the high level biology overview empowering.

I now understand that to rewire the amygdala, I have to reassociate certain sensory input with calm experiences - which is to say, facing your fears is essential for conquering anxiety.

Similarly, it's useful to understand how personal wellness activities such as meditation, breathing, exercising, and planning all have an impact on both the amygdala and cerebral cortex in a way that reduces anxiety in the brain.

I hope this summary has been a useful guide, and that you've walked away with some actions you can take to get in control of your anxiety. The book contains a lot more details and examples, so if you can put up with a lot of redundancy, reading it give you a deeper understanding of how the biology all stitches together. The second half of the book is almost like a workbook, with detailed questions and exercises that will really help you diagnose and take action to rein in your anxiety.