The Triune Brain

Understanding Your Mind’s Operating System

Imagine your brain as a three-story house. Each level has a unique function, yet all are connected by staircases and hallways. Ideally, these floors work in harmony, allowing for smooth communication and seamless transitions between instinct, emotion, and reason. But what happens when a door gets stuck, a staircase collapses, or one floor takes over the entire house? This is where understanding the Triune Brain—a model of how different parts of the brain interact—can provide insight into mental health, emotional regulation, and the effectiveness of different therapeutic approaches.

While this model simplifies the brain’s complexity and has faced criticism for oversimplification, it serves as a useful framework for understanding different aspects of mental and emotional health.

What Is the Triune Brain?

The Triune Brain is a model proposed by neuroscientist Paul D. MacLean in the 1960s. While modern neuroscience recognizes that the brain is more interconnected than this model suggests, it remains a helpful framework for understanding how we process experiences and emotions. The Triune Brain is composed of three “floors” of our metaphorical house: 

The Basement: The Reptilian Brain (Survival & Instincts)

The basement is the oldest and most primitive part of the house. It controls automatic, life-sustaining functions like breathing, heart rate, and digestion. It also houses our survival instincts—fight, flight, freeze—designed to keep us alive in dangerous situations. This is the part of the brain that reacts instantly to a loud noise, a near miss in traffic, or an unexpected confrontation. It doesn’t analyze—it just acts.

The Main Floor: The Mammalian Brain (Emotions & Memory)

The main floor is where we live day-to-day. It’s the home of emotions, social bonds, and memory. This is where the limbic system—including structures like the amygdala (our emotional alarm system) and the hippocampus (our memory processor)—resides. If you’ve ever had a smell instantly transport you to a childhood memory, that’s your main floor at work. This part of the brain helps us form relationships, interpret social cues, and decide whether something is safe or dangerous based on past experiences. However, if the basement sends a distress signal, the main floor can quickly become overwhelmed by fear, anxiety, or sadness.

The Upstairs Suite: The Human Brain (Logic & Self-Awareness)

The top floor is the most advanced—it’s where logic, planning, reasoning, and self-reflection happen. This is the neocortex, the part of the brain that allows us to think critically, manage emotions, and make long-term decisions. It helps us pause before reacting, consider different perspectives, and plan for the future.

However, when the basement is flooding (i.e., the reptilian brain is in survival mode) or the main floor is in chaos (i.e., the mammalian brain is overwhelmed with emotion), the top floor may go offline. That’s why when we’re anxious, afraid, or triggered, it’s hard to think clearly—we’re literally stuck on the lower floors of the house.

Your brain is like a house with three levels—instinct, emotion, and reason. When stress or trauma disrupts communication between floors, it can leave you feeling stuck, anxious, or overwhelmed.

Information Processing At Each Brain Level

Each floor of our metaphorical house processes information differently, influencing how we experience and respond to the world:

• • The Basement (Reptilian Brain): Think of this as an automatic security system. It detects danger and reacts instantly—without asking for permission. If a fire alarm goes off, it doesn’t pause to consider if it’s a drill; it just sounds the alarm. This part of the brain operates on instinct and routine, ensuring survival but often overreacting to modern-day stressors like work deadlines or social anxiety.
  • The Main Floor (Mammalian Brain): This is the emotional heart of the house. It processes memories, social bonds, and feelings, shaping how we interpret situations based on past experiences. If the basement detects a threat, the main floor decides how we feel about it. Is this a minor inconvenience or a full-blown crisis? It’s also where we store emotional memories—both joyful and traumatic—which influence how we respond to similar situations in the future.
  • The Upstairs Suite (Human Brain): This is where the rational homeowner lives. It engages in conscious decision-making, planning, and problem-solving. It evaluates the alarms from downstairs, assesses emotional cues from the main floor, and decides on the best course of action. However, if the basement is in panic mode or the main floor is overwhelmed, this level can become inaccessible—making it difficult to think clearly, stay calm, or make rational decisions.

Understanding how these floors interact helps explain why we sometimes react emotionally before thinking, why old traumas resurface unexpectedly, and why certain therapeutic approaches work better for different types of emotional distress.

How Information Moves Through the House (& What Can Go Wrong)

Ideally, all three floors communicate smoothly. The basement sends alerts, the main floor processes emotions, and the upstairs makes rational decisions.

In an ideal scenario, these regions communicate seamlessly:

• • The reptilian brain detects a potential threat.
  • The mammalian brain assesses emotional significance based on past experiences.
  • The human brain evaluates the situation rationally and decides on the best course of action.

However, during traumatic or overwhelming experiences, this communication can falter. For instance, the reptilian and mammalian brains may dominate responses, leading to instinctual reactions without rational evaluation. This can result in heightened anxiety, impulsivity, or emotional numbness.

The Triune Brain & Mental Health

Different mental health challenges reflect imbalances between these brain regions:

• • Anxiety: The basement is on high alert, constantly perceiving threats. The main floor follows suit with emotional distress, making it difficult for the upstairs to think rationally.
  • Depression: The basement may be in shut-down mode, while the main floor is stuck in a loop of negative memories and emotions and the upstairs struggles to find motivation or solutions.
  • Trauma: The basement’s alarm system is stuck in the “on” position, making it hard to feel safe even in calm situations.

When trauma or stress overwhelms the system, the basement (instincts) and main floor (emotions) can take over, shutting out rational thinking. This is why logic alone isn’t always enough to heal deep emotional wounds.

Top-Down vs. Bottom-Up Therapy: Fixing the House from the Inside Out

When something goes wrong in a house, you have two options: you can repaint the walls and rearrange the furniture (a surface-level fix), or you can go down to the foundation and repair the structural issues causing the cracks. The same applies to therapy.

• • Top-Down Therapies work from the upstairs down, focusing on thoughts and behaviors. These approaches—like Cognitive Behavioral Therapy (CBT)—aim to change how you interpret situations, helping you think your way out of distress. While useful, top-down methods often struggle to reach the root of the issue if deeper emotional wounds or trauma responses remain unresolved.
  • Bottom-Up Therapies work from the foundation up, targeting stored trauma, emotional imprints, and physiological responses. Approaches like Somatic Therapy and Eye Movement Desensitization and Reprocessing (EMDR) go beyond logic, working directly with the emotional and instinctual floors of the house to repair deeper structural issues.

Choosing the Right Approach: Fixing the House from the Foundation Up

Different therapies target different levels of the house. If a storm has shaken the foundation, repainting the walls won’t prevent further damage—you need to reinforce the structure first. The same is true for mental health.

• • Top-Down Approaches (Upstairs First): Works best when the upstairs is accessible. It helps reorganize thoughts and behaviors, like redecorating a room to make it feel more functional. But if the main floor is flooded with unresolved emotion or the basement alarm is constantly blaring, CBT alone may not be enough.
  • Bottom-Up Approaches (Foundation First): These therapies go deeper, addressing the root cause of distress. EMDR helps process traumatic memories stuck on the main floor, while Somatic Therapy helps release tension trapped in the basement, resetting the body’s stress response. These methods ensure the house is stable before redecorating, allowing for real, lasting change.

For true healing, addressing all levels of the house is key. While top-down approaches can help with everyday challenges, bottom-up therapies repair the foundation, allowing you to build a home that feels safe, stable, and truly your own.

Curious about where different therapies work on the brain? We’ve got you covered.

Top-down therapies like CBT focus on thoughts and behaviors, while bottom-up therapies like EMDR and Somatic Therapy address trauma at its root—healing the foundation rather than just redecorating the upstairs.

Final Thoughts

Your brain is like a house—each level plays a vital role, but balance and communication between floors are key to emotional well-being. Therapy can help reopen staircases, repair damage, and ensure that when distressing events occur, you can move between all three floors rather than getting stuck.

So Reach Out. We’re here to help.