Plasticity, Proliferation, and Survival

Lesson objective:

In this lesson, we recall the physicality of the brain and how it is affected by stress and trauma. We also learn about brain plasticity and proliferation strategies that we can use to enhance the emergence of neural tissue.

When we talk about resilience, it is important to talk about the physical brain and its ability to change, to renew itself–its synapses and cells. 

Indeed, just as the brain and body seem to collude to produce all sorts of unwanted responses after stress and trauma, the brain and body can also work together to recover and heal.

We mentioned earlier that there are 86 billion neurons in the brain. Trauma and stress affect these neurons, particularly in the amygdala, hippocampus, and prefrontal cortex. This can cause dendritic atrophy and shrinkage, fortifying and increasing certain communication pathways while reducing others.

Importantly, though, the brain is moldable, pliable, malleable. 

In other words, it can change.  

Experiences in the external world can change it. We call this plasticity. Like melted or soft plastic, the brain can change shape, form, and internal pathways between its neurons. And indeed, while stress and trauma impact the plastic brain, we also have the capacity to strategically reshape it.

First, just as neurons can shrink or disappear with chronic stress and trauma, they also can regenerate and grow. 


We call this neurogenesis. 

Neurogenesis is the creation of new neurons. Neurogenesis happens every 4–6 weeks, meaning that the brain regularly creates new neurons every few weeks.

In each neurogenesis cycle of 4 to 6 weeks, new stem cells emerge. 

This process begins in the olfactory bulb and the hippocampus, which is, ironically, one of the areas most negatively affected by chronic stress.

In the process of neurogenesis, stem cells created in the hippocampus do not have a specific role yet. They can differentiate and evolve into any type of cell in the body. And stem cells generated in the brain become new neurons in each cycle.

When we talk about neurogenesis, we focus on two essential processes: 1) proliferation and 2) survival. 

Neuronal proliferation is a rapid increase in the number of stem cells that turn into neurons. Neuronal survival refers to the number of these new neurons that survive to become well established; basically, it refers to how many neurons come into existence and how many survive into maturity and full usability.


Different strategies can be used to promote neuronal proliferation and neuronal survival, both of which correlate strongly with good mental health.

Importantly, though, the strategies for proliferation are not necessarily the same as the strategies for survival.

Proliferation seems to be most affected by exercise—specifically running and other physical activities. Some studies have found that when you engage in routine exercise, you are more likely to generate more stem cells that turn into neurons.

Neuronal survival, however, is more affected by environmental enrichment. Environmental enrichment includes a diverse set of creative cognitive activity inputs. It can include things like reading a book, solving a math problem, or engaging in an exciting new activity.

Overall, research has shown that exercise and environmental enrichment can help with proliferation and survival, respectively. In addition, an individual can use other practical things to promote neurogenesis, regain control, rebuild communication in the control tower, and reestablish the relationship between the elephant and the rider.

One way to enhance control and recovery is through practicing and strategically building interoception. If you recall, stress and trauma interrupt interoception. Interoception is essentially an awareness of bodily states. It is about being able to read the signs that our bodies are relaying to us.

Recognizing bodily states, and then moving to analyze and follow those signals, after a long period of stress or trauma. And the only way to consciously access these deeply felt, often automatic feelings, is through practicing listening and practicing self-awareness.

When strategically practicing interoception, you activate the medial prefrontal cortex, a part of the brain that allows you to interpret what you are feeling. To put it simply, practicing interoception is about forcing the rider to communicate with the elephant once again after a temporary separation.  

Deliberately engaging in interoception and actively thinking about what you are feeling and how you are responding to the world around you forces you to be more stimulated, which, in turn, helps with neuronal survival.

Furthermore, interoception enhances the cognitive environment, enhancing your ability to recognize and interpret and engage with inputs from the body. Over time and with practice, this allows for more neuronal survival, better communication within the control tower, and overall better mental health. 

So, take some time each day to practice a few skills that can help shape new neurons and their connections.