Before the Parts Speak: The Brainstem Layer IFS Therapists Should Know About
- Katie Helldoerfer
- Feb 21
- 5 min read
I want to say upfront that I love Internal Family Systems. I'm IFS Level 2 certified, I use it as the primary lens in my clinical work, and I believe deeply in the model's capacity to facilitate real, lasting healing. What follows isn't a critique of IFS - it's a question I've been sitting with as I train in Deep Brain Reorienting (DBR), a neurobiologically-informed trauma approach developed by psychiatrist Frank Corrigan. The question is this: is there a layer of physiological activation that fires before IFS work begins, that the model wasn't originally designed to address, and that might explain why some clients plateau in ways that are hard to account for?
I think the answer is yes - and I think naming it clearly actually serves IFS rather than undermining it.
The Timing Problem
When we sit down to do parts work, there's an implicit assumption that the nervous system is ready to engage - that the client can orient inward, locate a part, and access enough Self energy to begin the dialogue. But Corrigan's work on Deep Brain Reorienting points to something that complicates this assumption: the brainstem has already been doing its own work long before we ask the first question.
The sequence Corrigan describes - orienting tension (superior colliculi), preaffective shock (locus coeruleus), affective response (periaqueductal gray) - fires in milliseconds (Corrigan & Christie-Sands, 2020). By the time a client turns their attention toward a painful part, this sequence has already activated. The body has already registered something. And critically, this activation often has no language attached to it - it's subcortical, pre-verbal, below the level where narrative or meaning-making lives.
What this means clinically is that a client may be carrying the somatic weight of orienting tension and shock by the time we ask "how do you feel toward that part?" - and neither of us knows it. The activation doesn't always announce itself. It doesn't always look like distress. Which is where things get complicated.
Three Presentations, One Underlying Problem
In my clinical thinking, unaddressed subcortical activation tends to show up in roughly three ways - and all three affect the quality and reliability of Self energy, even when Self appears accessible.
The first is what I think of as the override client. Subcortical activation is present but manageable - this client has enough cortical capacity, or enough practiced suppression, to produce Self-like language and engage in parts dialogue. The session looks productive. The therapist experiences the client as Self-led. But something underneath is running quietly in the background, unaddressed. These clients often report feeling fine in session and confused about why nothing actually changes. The signal is there; it's just not being tracked.
The second is the collapse client. Here, subcortical activation overwhelms the system more visibly. Self energy fluctuates or disappears under stress. The client struggles to maintain the Self-to-part distinction. They may get labeled as too activated for parts work, or as resistant, or as having a particularly dense protector system — when what's actually happening is that the brainstem load is simply more visible in them. The underlying cause is the same as the override client. The difference is that this client can't suppress the signal as effectively.
The third presentation is the most interesting and the most easily missed: the client who genuinely accesses Self energy - real calm, real curiosity, real compassion toward parts - and yet subcortical activation is still stored beneath that Self state. These clients can do beautiful, meaningful parts work. Unburdening happens. Shifts occur. And then they find themselves retriggered in ways that feel confusing or demoralizing, because the brainstem layer that was running underneath the Self state never got addressed. Self energy became accessible despite the underlying activation, not because the system had fully settled. That's a more fragile foundation than it appears.
The through-line across all three is the same: subcortical activation operates independently of whether Self energy is accessible or not. This isn't only a story about the most dysregulated clients. It's relevant across the board.
What This Means Clinically
I want to be careful here, because this is where the argument could tip into "IFS doesn't work" - which is not what I'm saying. Affect work matters. Parts carry real emotional content. The Self-to-part relationship is genuinely healing. None of that is negated by what I'm describing.
What I am saying is that there's a layer beneath the parts system - a brainstem-level layer of orienting, shock, and affective response - that IFS wasn't originally designed to address, and that tending to it changes what's possible in the work above it. Corrigan's randomized controlled trial of DBR found large, sustained reductions in PTSD symptoms specifically by targeting this subcortical sequence directly - with 52% of participants no longer meeting PTSD criteria at three-month follow-up (Kearney et al., 2023). The implication is that when the physiological sequence is addressed at the level where it actually lives, the system can reorganize in ways that cortical and affective approaches alone often cannot produce.
This points toward two clinical priorities that I think belong in how we approach trauma work more broadly. The first is creating subcortical regulatory space before or alongside parts work - not as a rescue intervention when things go wrong, but as a gentle default that gives the brainstem layer room to settle before we ask the personality system to do its work. The second is somatic attunement as an ongoing tracking skill - watching for the quality of the client's stillness, the presence or absence behind the eyes, the subtle orienting tension that may signal activation the client has no language for. Reported affect and Self-like language are not always sufficient indicators of what the nervous system is actually doing.
IFS maps the personality system with extraordinary precision. DBR works below it, at the level where shock and orienting patterns are stored. These aren't competing frameworks - they're working at different altitudes. But knowing that the lower altitude exists, and that it fires first, changes how we sequence the work and what we track along the way.
A Note on Humility
I'm writing this from inside a training, not from a place of established expertise in DBR. These are clinical hypotheses I'm developing in real time, drawing on Corrigan's framework and my own experience sitting with clients whose IFS work has plateaued in ways I couldn't fully account for. I'm holding this lightly, and I'd genuinely welcome pushback, nuance, and dialogue from others thinking at this intersection.
What I'm most confident about is this: the clients who get labeled resistant, or whose progress doesn't hold, or who feel fine in session and unchanged in life - they deserve a more precise clinical account of what might be happening. This is one attempt at that.
*
References
Corrigan, F. M., & Christie-Sands, J. (2020). An innate brainstem self-other system involving orienting, affective responding, and polyvalent relational seeking: Some clinical implications for a 'Deep Brain Reorienting' trauma psychotherapy approach. Medical Hypotheses, 136, 109502. https://doi.org/10.1016/j.mehy.2019.109502
Corrigan, F. M., & Young, H. (2025). The psychopathological domains of attachment trauma: A commentary. Clinical Neuropsychiatry, 22(5), 387–391.
Kearney, B. E., Corrigan, F. M., Frewen, P. A., Nevill, S., Harricharan, S., Andrews, K., Jetly, R., McKinnon, M. C., & Lanius, R. A. (2023). A randomized controlled trial of Deep Brain Reorienting: A neuroscientifically guided treatment for post-traumatic stress disorder. European Journal of Psychotraumatology, 14(2). https://doi.org/10.1080/20008066.2023.2238690
Schore, A. N. (2019). Right brain psychotherapy. W. W. Norton.
Schwartz, R. C. (2021). No bad parts: Healing trauma and restoring wholeness with the Internal Family Systems model. Sounds True.
van der Kolk, B. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma. Viking.
*
About the Author: Katie is a Licensed Professional Clinical Counselor (LPCC-S) and board-certified art therapist (ATR-BC) at Lacuna Counseling in Columbus, Ohio. She is IFS Level 2 certified. Katie specializes in neurodivergent-affirming therapy, integrating Internal Family Systems, art therapy, and somatic approaches.
