What's the difference between top-down therapy and bottom-up therapy?

Top-down models and bottom-up models are two approaches used in therapy. Top-down approaches include a focus on cognition and correcting unhelpful thought patterns and beliefs about the world. While some find this approach to be effective in a variety of situations, its usefulness can be limited for someone with experiences of trauma.

Bottom-up processing involves a focus on emotions and physical sensations instead of beginning with cognition. This article reviews the function of different brain areas to more thoughtfully understand uses and limitations of top-down and bottom-up approaches to counseling.

To help conceptualize these two models, we’ll look at the human brain in three different sections. The first, oldest, and most primitive part of the brain is the brain stem. Trauma research refers to this as the reptilian brain, due to its presence in reptiles, however the brains of reptiles have not evolved beyond this.

The second oldest part of the brain is the limbic system, and trauma research calls this the mammalian brain. As you might assume, this is present in the brain of mammals, and their brains have not developed beyond this point.

What makes humans unique is the neocortex - a brain structure developed over time through the course of evolution. As we look at the human brain, each structure (brainstem, limbic system, and neocortex) are quite literally stacked on top of each other. The reptilian brain is the control center for our survival instincts, the limbic system is responsible for our emotions, and the neocortex is responsible for thought and cognition.

Reacting to trauma during trauma

When a traumatic event happens, our body registers that something is threatening our wellbeing. In this case, our reptilian and mammalian brain jump into action and work together to keep us safe. Our amygdala (in the mammalian brain, responsible for emotions) tells us we are scared, and tells the hypothalamus (in the mammalian brain, responsible for maintaining homeostasis) to release adrenaline. The brainstem (reptilian brain) then enters fight or flight mode. The sympathetic nervous system is activated, and adrenaline increases heart rate and blood pressure, sending more blood to our muscles so we can fight back or run away.

During trauma, lower brain structures also shut down everything the brain is doing that is not necessary for survival. Every action and inaction is the result of our body doing its best to protect itself. It is okay and good that this happens, this is how we SURVIVE trauma. So we can and should be thankful for our reptilian and mammalian brain during these experiences. 

After traumatic exposure

After the body and brain exhaust themselves keeping you alive, they react differently than before the trauma. The brain recognizes that all of its efforts kept you alive, however it perceives that anything remotely similar to the trauma should require the same output of intense reactivity and efforts toward protection.

When a trauma reminder occurs (a trigger), the amygdala and other parts of the brain say, “We’ve been here before, we know what to do,” and you jump back into fight or flight, which is problematic when you aren't actually in danger. You are taken away from the present moment, and straight to the moment of trauma. Your body experiences the same emotions and physical sensations it did during the trauma. 

This is especially impactful when someone experiences chronic exposure to trauma, or experiences trauma when their brain is still developing. When chronic or developmental trauma occurs, the brain learns over time that higher functioning brain structures (i.e. the prefrontal cortex, responsible for things like impulse control, reasoning, and emotion regulation) are not useful. In childhood, this affects how much these important structures are actually able to develop; and in chronic exposure to trauma, the brain will stop utilizing some brain structures even if they are available and ready to use. 

When trauma triggers occur and the body shuts down higher-order processes, we see reactivity, intense emotions, and difficulty staying present and feeling safe. Over time or with chronic exposure to trauma, anything vaguely threatening flips the switch into fight or flight mode.

Developmental trauma involving abandonment by a caregiver could lead to a hyper-alert watchfulness for any sign that someone is leaving you, and triggering an inability to thinking rationally about another person's behavior, intentions, or perspective. You act from emotion and self-preservation desparate to restore a semblance of safety, however this doesn't actually result in safety, it leaves you stuck in a constant 'dread state', sensing, “something bad is about to happen”. 

Top-down versus bottom-up in traumatized individuals

Top-down models such as cognitive behavioral therapy focus on the neocortex, which is the logical brain. Techniques such as reframing unhelpful thoughts address logical and rational thinking, rather than emotions and physical sensations. This is an effective evidence-based therapy, and it must also be considered that for those who have experienced trauma, maladaptive thoughts are often the byproduct of intense emotional experiences and physiological reactions that come with trauma reminders.

For those exposed to chronic trauma or with a history of developmental trauma, the neocortex does not function the way it should. Correcting thought patterns and beliefs provides specific benefits for those impacted by trauma, and we can see the limitations of top-down models when attempting to address trauma by approaching the brain in a 'backward' fashion. A focus on shifting cognition does not allow getting to the root of what has damaged cognition in the first place.

This brings us to bottom-up models. Bottom-up processing aims to address the lower areas of the brain before addressing the top areas. Bottom-up models involve first learning how the body reacts physiologically to trauma reminders and emotional stressors when its sent into fight, flight, or freeze.

Different models function in their own ways to bring awareness, compassion, and curiosity to physiological sensations and strong emotional reactions, giving an understanding to why a particular reaction occurs when you are triggered. After gaining awareness and understanding of your reactions, bottom-up models aim to use therapy as a source of grounding and stability to safely process your experiences. When you are grounded, stable, and present in the therapy room, you can visit experiences stored in the lower areas of your brain without the overwhelm you might feel had you not first laid the groundwork.

After time and consistency in therapy, one foot can remain in the present while the other explores the past, over time reducing the impact of these events on your wellbeing and quality of life.

References

National Center for Biotechnology Information. (2018). The endocrine system increases the flow of blood to large muscles. In StatPearls [Internet]. Retrieved June 14, 2024, from https://www.ncbi.nlm.nih.gov/books/NBK541120/#:~:text=The%20endocrine%20system%20increases%20the,of%20blood%20to%20large%20muscles.

Sciencedirect. (n.d.). Triune brain. In ScienceDirect Topics. Retrieved June 14, 2024, from https://www.sciencedirect.com/topics/medicine-and-dentistry/triune-brain#:~:text=The%20oldest%20layer%20of%20the,brains%20of%20snakes%20and%20lizards.