Two-Story House: An Analogy to Understand the Brain

First Level: Downstairs

The downstairs brain, often referred to as the reptilian or primitive brain, contains the brain stem, limbic region and the amygdala. This instinctive part of the brain is well developed from birth and is responsible for:

• Basic functioning – breathing, blinking, heart beating, flinching, digestion etc.

• Innate responses – fight, flight, freeze and flop.

• Producing strong emotions such as anger and fear.

When viewed as a house it is where all necessities of living occur: the kitchen, laundry, dining, living room, and bathroom.

Second Level: Upstairs

The upstairs brain is significantly more sophisticated than the downstairs brain and is made up of the cerebral cortex and its various parts, in particular the middle prefrontal cortex. This part of the brain is responsible for:

• Higher-order thinking and planning

• Imagining

• Analyzing and problem-solving

• Sound decision-making.

The upstairs provides a fuller perspective of the world and enables us to emotionally regulate and to have control over our body. When this part of the brain is working well, we are able to utilize self-understanding, empathy and morality, as well as consider consequences and think before we act.

Within the house analogy, the upstairs brain can be imagined as a light filled, airy, second story study, library or bedroom filled with windows and sky lights, enabling us to see the world more clearly. The upstairs brain does not reach full development until our mid-twenties and thus this upstairs level of our house remains under constant construction and renovation until then – with parts of the roof missing and debris lying all around the floor. Put simply, this part of the brain is not capable of functioning all of the time and thus children cannot always access their ability to make sound decisions, control their behavior or show empathy.

Staircase: Connecting the downstairs and upstairs

The two levels of our brain are linked by a metaphorical staircase that allows the flow of information. This allows the upstairs to monitor the actions of the downstairs and calm strong emotions, reactions and impulses. When working well, the staircase enables us to consider the emotional and physical messages coming from the downstairs brain and use the thinking and analyzing upstairs brain to determine a course of action. In other words, when our upstairs brain is working well, we are able to manage impulses and emotions and use both logic and reasoning in stressful situations.

But, in times of high emotion and stress, we can find ourselves being ‘trapped downstairs’ unable to access the logic and problem-solving of the upstairs brain.

The Baby Gate of the Brain: The Amygdala

The amygdala is a small almond shaped structure located within the downstairs brain. The amygdala is responsible for processing and expressing emotions, especially anger and fear, and is always on the lookout for danger or threats. When the amygdala senses danger, it can overrule the upstairs brain and take over, enabling us to act before we think. This is sometimes referred to as an "amygdala hijack." Our brains are purposefully designed this way to keep us safe and help us survive. In other words, our brains will allow us to find safety in dangerous situations without having to think or plan.

However, when we are not in mortal danger, acting before we think usually does not have the best consequences. Dan Siegal, a clinical professor of psychiatry at the UCLA School of Medicine and executive director of the Mindsight Institute, refers to as "Flipping our Lids." When this happens, the amygdala takes control and relieves the upstairs brain from becoming involved.

The amygdala can fire up often in times of high emotion and stress, shutting the ‘baby gate’ at the bottom of the stairs and restricting access to the upstairs brain. When this happens, we can find ourselves not only contending with an incomplete upstairs brain but also not being able to reach the parts of the upper brain that do work. This can make it very difficult for us to act calmly and reasonably or to use sound judgement.

Source: The Upstairs and Downstairs Part of the Brain