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Understanding trauma’s neuroscience can be validating for sufferers, and can inform effective treatment.

Amygdala, prefrontal cortex, Broca's area, and hippocampal changes can keep survivors trapped in the past.

Trauma doesn't just hurt your feelings; It rewires four key brain regions in measurable, well-documented ways.

Over a year ago, I wrote a post about how trauma is "not just in your head". Here, I follow it up with corroborating evidence. I’ve dedicated most of my life to treating trauma using emotionally-focused and EMDR therapies. And I’ve been ceaselessly obsessed with how and why it works.

I also see versions of brain diagrams circulating on social media constantly; colorful infographics breaking down how trauma affects key brain regions. And while I tend to cringe at oversimplified mental health memes, this one is actually onto something quite important. The neuroscience of trauma is well-documented, illuminating, and validating to survivors and their loved one(s). I believe it’s also deeply relieving and humanizing for anyone traumatized who has ever wondered: what’s wrong with me? Or, why can't I just get over this?!

Here, I summarize the four most affected brain regions and their connection to people trying to heal from real pain (as I’ve stated in a prior post, “trauma” originates from the Latin word “wound”).

1. The Overstimulated Amygdala: Your Brain's Misfiring Alarm System

To me, the most useful way to think of the amygdala is as your brain's main threat-detection system. Under ideal circumstances, it fires when there's genuine danger, helps you respond effectively, and then settles back down once the threat is addressed. With trauma (defined by someone's reaction to an event, rather than the event itself), that system not only gets stuck on "on", but I'd argue that the brain’s lever keeping it “on” metaphorically rusts and locks it on “on,” despite one’s best intentions to lubricate the dial so it can move fluidly, depending on current threats. Functional imaging studies consistently show that PTSD sufferers demonstrate heightened amygdala activation in response to threatening cues, paired with reduced activity in the prefrontal regions that would ordinarily dial it back (Kredlow et al., 2022; Etkin & Wager, 2007). The result is a nervous system perpetually scanning for danger (and, like the confirmation bias, it looks for information that confirms existing beliefs). It assumes danger and therefore finds it, even when none is present, or danger is minimal.

This is why trauma survivors aren't being dramatic when a lightly slammed door startles them, when they freeze at an unexpected touch, or when they can't seem to relax in objectively safe environments. As said, their brain has been powerfully trained neurobiologically to stay vigilant (even when vigilance isn’t necessary). As I wrote about previously, this brain glitch is not a character flaw; it's a sensitized alarm system that saved their life once or more and hasn't gotten the memo (and/or doesn’t trust the memo) that the threat has passed.

2. The Affected Prefrontal Cortex: When Rationality Goes Offline

To me, the most useful way to think of the prefrontal cortex (PFC) is as your brain's conductor or CEO. Its job is rational thinking, decision-making, strategy, tact, and most critically, appraising and regulating emotional responses from the amygdala. In trauma survivors, this control is disrupted. Research published in Neuropsychopharmacology describes a well-supported model in which the ventromedial (“ventro “refers to front, and “medial” refers to middle in brain anatomy) PFC, which normally manages and inhibits the amygdala, becomes hypoactive while the aforementioned amygdala becomes hyperactive. This imbalance makes it much harder to regulate fear. (Kredlow et al., 2022).

This is why trauma treatment isn't simply about thinking differently, a common misconception I frequently hear about, even from health and mental health professionals. I repeat: You can't logic your way out of a nervous system in overdrive. When the PFC goes offline under stress, the capacity for rational thinking, perspective-taking, and emotional management all take a significant hit. It also helps explain why traditional talk-therapy alone, while valuable, can prove ultimately insufficient for many trauma survivors, because it can inadequately address the body and brain's alarm system directly.

3. The Underactive Broca's Area: Why "Putting It Into Words" Can Feel Impossible

Have you ever had the experience of knowing exactly what you felt but couldn't find adequate or aligning words? I know I have. That's not weakness or avoidance, but neurobiology. Our lived experiences and the robustness and richness of our emotional lives can go way beyond the limits of language, especially for trauma survivors.

Broca's area, located in the left inferior (bottom) frontal gyrus (one of the brain’s main communication hubs), is central to language production and labeling experience (especially felt language). Neuroimaging research has consistently replicated that the Broca's area shows decreased activity when trauma symptoms arise in PTSD (Hull, 2002), especially at the key moment that the amygdala is hyperactivated (Rauch et al., 2006; Hull, 2002). One review described this deactivation as the likely explanation for the difficulty trauma survivors have in applying words to their feelings and experiences, essentially going speechless when trauma memories get activated (Hull, 2002). This is why in EMDR therapy, we often ask the person periodically what they're noticing verbally as they have the trauma in their attentional background while they engage in fast eye movements.

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To me, this has profound clinical implications. It helps explain why asking someone to talk through their trauma in a highly activated state can feel, and neurologically be, nearly impossible. It's also a compelling argument for body-based and sensory modalities like EMDR (and somatic experiencing therapy), which do not require the client to verbally narrate what they're noticing as they focus on the trauma for healing to occur (Shapiro, 2017). The brain literally can't always put it into words, from trauma-based overwhelm, and therefore often shuts down, like a computer with too many programs running on it simultaneously (or one that overheats from hot weather) until it eventually forces a restart or shut down.

4. The Reduced Hippocampus: When Past and Present Collapse

The hippocampus is essential for contextualizing and forming memory, helping us file experiences into a coherent timeline with clear markers of then and now. If you have a MacBook, you can think of it as the "Finder" of folders that are essentially labeled in the order of time. In PTSD, hippocampal volume reduction is one of the most consistently replicated neurobiological findings in the literature I’ve seen. In fact, hippocampal volume may best distinguish PTSD sufferers from trauma-exposed controls who did not develop the disorder (Zilcha-mano et al., 2023).

This means traumatic memories often lose their anchoring in time. They don't feel like memories of something that happened in the past, but something still happening right now. A smell, a voice, a particular quality of light can transport a trauma survivor into a full-body re-experience that feels present-tense. This isn't a hallucination; it's the hippocampus failing to stamp the memory with "past" and "safe." Luckily, research also suggests that hippocampal volume can increase with successful treatment, offering genuine hope/proof that these changes are not permanent (Zilcha-mano et al., 2023).

These findings are why I push back, gently but persistently, when anyone implies that trauma is "just in your head" or that survivors should simply will themselves into recovery. These four brain regions: the amygdala, prefrontal cortex, Broca's area, and hippocampus are measurably altered in trauma sufferers. The suffering is biological, somatic, physiological, and emotional, not just mental. And the most effective treatments for trauma, such as EMDR, somatic experiencing, and emotionally focused therapy, among others, work precisely because they involve these neurobiological realities rather than trying to merely talk around them.

Understanding the brain changes after trauma isn't just intellectually compelling, but validating. It reframes the experience from “What's wrong with me?” to “This is what happened to my brain.” That shift alone is, to me, pivotal in spearheading healing.

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Etkin, A., & Wager, T. D. (2007). Functional neuroimaging of anxiety: A meta-analysis of emotional processing in PTSD, social anxiety disorder, and specific phobia. *American Journal of Psychiatry, 164*(10), 1476–1488. https://pubmed.ncbi.nlm.nih.gov/17898336/

Hull, A. M. (2002). Neuroimaging findings in post-traumatic stress disorder: Systematic review. The British Journal of Psychiatry, 181 (2), 102–110. https://pubmed.ncbi.nlm.nih.gov/12151279/

Kredlow, M. A., Fenster, R. J., Laurent, E. S., Ressler, K. J., & Phelps, E. A. (2022). Prefrontal cortex, amygdala, and threat processing: Implications for PTSD. *Neuropsychopharmacology, 47*(1), 247–259. https://pubmed.ncbi.nlm.nih.gov/34545196/

Rauch, S. L., Shin, L. M., & Phelps, E. A. (2006). Neurocircuitry models of posttraumatic stress disorder and extinction: human neuroimaging research--past, present, and future. Biological psychiatry, 60(4), 376–382. https://doi.org/10.1016/j.biopsych.2006.06.004 https://pubmed.ncbi.nlm.nih.gov/16919525/

Shapiro, F. (2017). *Eye movement desensitization and reprocessing (EMDR) therapy* (3rd ed.). Guilford Press. https://www.guilford.com/books/Eye-Movement-Desensitization-and-Reprocessing-EMDR-Therapy/Francine-Shapiro/9781462532766?srsltid=AfmBOopbV2Jsh35kferdceFh8SSKf9vRGkMTMra7ciAhQ6SUuyb0WHCN

Zilcha-Mano, S., Duek, O., Suarez-Jimenez, B., Zhu, X., Lazarov, A., Helpman, L., Korem, N., Malka, M., Harpaz-Rotem, I., & Neria, Y. (2023). Underlying Hippocampal Mechanism of Posttraumatic Stress Disorder Treatment Outcome: Evidence From Two Clinical Trials. Biological psychiatry global open science, 3(4), 867–874. https://doi.org/10.1016/j.bpsgos.2023.01.005 https://pubmed.ncbi.nlm.nih.gov/37881552/

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