Wait—don’t run! I know you saw the word “brain” and thought, Oh no… science. And yes, you’re right. But I promise to keep the science part simple and digestible.
Previously, we explored what trauma is and touched on how it can affect us. In this blog, we’ll dive deeper into how trauma impacts both the brain and the body. While the brain is incredibly complex (and we could write entire books on it), let’s focus on the essential parts to help us better understand trauma’s effects.
The Brain: Built from the Bottom Up
Dr. Bruce Perry describes the brain as hierarchical, meaning it develops from the bottom up:
- Brainstem – Controls basic survival functions like heart rate and the fight-or-flight response.
- Limbic System – Manages emotions and relationships.
- Cortex – Responsible for thinking, reasoning, and self-control.
Dr. Dan Siegel further breaks this down into two primary areas:
- The “Downstairs Brain”
Includes the brainstem and amygdala — responsible for survival and emotional responses.- The amygdala, often called the fear center, becomes overactive during trauma.
- This can leave a person in a constant state of hypervigilance, anxiety, or panic.
- The “Upstairs Brain”
Includes the prefrontal cortex — responsible for logic, decision-making, and empathy.- Trauma can cause the prefrontal cortex to become underactive, making it difficult to concentrate, make decisions, or regulate emotions.
- The hippocampus, which processes memory, is neither upstairs or downstairs, but still plays a major role in how we process trauma This is where we process memories. Trauma may cause the hippocampus to shrink — resulting in fragmented or unclear memories of the trauma.
When we experience trauma, our brain can “flip its lid.” This means the thinking part of the brain goes offline, and the emotional, reactive part takes over. We become more likely to react impulsively—whether by freezing, fleeing, fighting, or fawning.
State-Dependent Functioning
Dr. Perry also explains a concept called State-Dependent Functioning. When we’re in a state of high stress, the brain shifts into survival mode. So when someone asks, “What were you thinking?” — the honest answer may be: You weren’t. Trauma interrupts our ability to think clearly because the brain and nervous system are in protection mode.
This dysregulation of the nervous system can leave a person stuck in a state of chronic alertness—long after the actual danger has passed.
A Relatable Example: The Eye Puff
Recently, I was talking to a friend about how the brain changes with repeated trauma—especially in early life. The best way I could explain it was with a simple, universal experience: the puff of air at the eye doctor.
You know it’s coming. Every time you rest your chin on the machine, you’re told it’s about to happen. And still—you flinch. Your brain has been conditioned to react, even if there’s no puff. This is how trauma can work: our brain rewires itself based on past experiences. Even when the threat is gone, the body still remembers.
This doesn’t mean eye doctors are traumatic—it’s just a relatable way to understand how repeated experiences shape the way we react.
Trauma Shapes How We See the World
Let’s look at this another way. A person raised in a safe neighborhood might feel fine leaving their doors unlocked. Someone in a high-crime area might double-check the locks three times. Neither is wrong—it’s just a reflection of what their brain has learned is necessary for safety.
Now apply that to trauma. Imagine a child who was abused from ages 1 to 10. If they grew up without other supportive adults, they might come to believe that love looks like control, pain, or fear. That child might grow up distrusting others, struggling with affection, or reacting aggressively—not because they’re “broken,” but because their brain adapted for survival.
Of course, everyone’s response to trauma is different. Not everyone who experiences trauma will develop the same behaviors. Genetics, age, support systems, and resilience all play a role.
The Body Keeps the Score
But what about the rest of the body?You’ve probably heard the phrase “the body keeps the score.” It’s the title of Dr. Bessel van der Kolk’s well-known book. Spoiler alert: it does — and let’s just say, the body and stress are not exactly besties. Trauma moves in, and the body takes the hit.
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Trauma-related physical symptoms can include:
- Digestive issues (like IBS or stomach pain)
- Chronic pain or muscle tension
- Autoimmune issues or inflammation
- Sleep problems and fatigue
- Increased risk for heart disease and diabetes
As Dr. Bessel van der Kolk explains, trauma is not just remembered in the mind—it’s stored in the body. That can look like:
· Tight muscles or chronic pain
· Panic without a clear cause
· Heightened startle responses
· Flashbacks triggered by smells, sounds, or touch
Even when the mind forgets, the body remembers.
There Is Hope for Healing
Everyone responds to trauma differently, but healing is possible. Dr. Perry offers several principles for trauma recovery:
- Neurosequential Development
The brain builds in stages. Trauma disrupts this process, so therapy must meet people where development was interrupted. - Healing Through Relationships
Safe, consistent relationships help rebuild trust and rewire the brain for safety. - Rhythm Regulates
Repetitive, rhythmic activities (like music, drumming, or movement) help calm the nervous system. - Regulate → Relate → Reason
Before we can connect with others or work through trauma, we need to regulate our nervous system.
Because trauma lives in the body, healing must involve the body—not just the mind.
Effective body-based approaches include:
- Somatic experiencing
- Yoga, breathwork, and movement
- EMDR (Eye Movement Desensitization and Reprocessing)
- Grounding techniques and body awareness
- Safe, supportive touch
🌱 Final Thoughts: You Can Heal
Understanding how trauma affects the brain and body isn’t just about recognizing what went wrong — it’s about creating pathways to healing..