We naturally lose neurons and synapses as we age. So why are adults so much more capable than infants? Because it’s not just about the number of neurons you have, but how well they communicate with each other. As neurons are stimulated they create more branches, called dendrites, into each other so they can communicate more efficiently. This is called neuroplasticity, or the ability to build a pathway in the brain. The more developed your neuronal communication network becomes, the more function you have. This is why botanicals that are able to promote dendrite growth, such as bacopa monnieri and Lion’s Mane mushroom, are so valuable.
The average adult brain has more than a hundred billion neural cells, which when connected, give us almost unlimited potential for creativity and insight. Like widening a road as traffic increases, when we think an increased flow of thoughts on a topic, or practice an increased quantity of an action, the number of neurons our bodies require to route the information increases, similar to how our muscles bulk up with increased exercise. In this way our emotions and behavior shape our brains and subsequent experience as they stimulate the formation of neural pathways that either reinforce old patterns or initiate new ones.
How do you know what your level of neuroplasticity is? Ask yourself if it’s harder or easier for you to learn something new or acquire new skills than it was 5 years ago. If it’s easier, then you’ve developed a brain with greater plasticity potential. If it’s harder, then you’ve developed a brain with inefficient plasticity and may also be losing neurons more rapidly. Remember, your brain function isn’t directly related to your age – as you get older you have the potential to develop either greater neuron plasticity or greater neuronal degeneration.
Positive and negative plasticity
Plasticity can be a good or bad thing. Just as we can develop plasticity to learn new skills, we can develop it to ingrain a bad habit or negative condition. Examples of negative plasticity include PTSD, chronic pain disorders, or anything else in which neuronal communicating pathways have become more efficient at creating negative responses. In the case of chronic pain, a person’s neuronal pathways that perceive and generate pain signals become more developed and efficient, and pain-receiving fibers increase in number and branch out to further activate pain perception.
Negative plasticity can involve any part of the brain, such as the limbic system, which governs emotion and survival. In PTSD researchers have found increased plasticity in the amygdala, which is responsible for fear, anger and rage and for stimulating the fight-or-flight response when you feel something is attacking you.
You don’t have to experience the trauma of war to develop negative plasticity. The more practice your brain has generating a stress response, whatever it is, the more efficient and better it gets at it. Over time, the negative plasticity from everyday stress can develop to the point a person can’t handle minor stress without insomnia, hypertension or anxiety. This is why it’s important to build activities that you enjoy into each day, which actively inhibits your negative stress response.
Conversely, positive plasticity can not only create a more joyful experience of life and allow you to quickly absorb new information and skills, but can even overcome physical disabilities caused by damage to the brain. Starting in the 1980s, neurologists and therapists began to observe that while a stroke patient’s MRI might continue to show damage in, for example, the part of the brain that controls the left hand, not infrequently the brain would somehow heal and functionality of the left hand would return. Finally they realized that the brain wasn’t healing in the sense of reconstituting the original brain tissue damaged by stroke, but rather the brain had adapted by strengthening alternative pathways to regain functionality of the affected part of the body. More and more of these remarkable cases eventually led to the understanding that the brain not only has the ability to reorganize itself, but is also able to generate new cells throughout our lifetimes.
While it was long thought that the brain created no new neuronal cells after birth, it is now known that the body constantly sends signals to stem cells in the hippocampus to differentiate into new neurons. Stem cells are blank cells that don't become specialized until stimulated by an epigenetic environmental signal, which means that the aging brain can regenerate. In addition to the hippocampus, neuronal stem cells are found in other areas of the brain and spinal cord, and far different from the old static picture of brain development, are generated by the body up until the very last moments of our lives.
Neurogenesis and neuroplasticity are intimately related and the factors that promote greater plasticity tend to also promote neurogenesis. For instance, a major component in neurogenesis is a protein called brain-derived neurotrophic factor (BDNF), which plays a key role in creating new neurons as well as protecting existing ones, helping to ensure their survivability while encouraging the connection of one neuron to another. The gene that turns on BDNF is activated by a variety of factors, including voluntary physical exercise (animals forced to exercise don’t demonstrate this change), calorie reduction, botanicals such as curcumin and gotu kola, and the omega-3 fat known as DHA.
Learning experiences and other highly attentive states of awareness like deep meditation also stimulate the formation of new neurons and the growth of new synaptic connections in the brain, especially in the hippocampus. The hippocampus is most active when the sensory data it receives comes from the real, natural environment; these enriched environments stimulate the formation of many more neurons than does simple, linear informational input, like what comes from a computer or television. But neurons are wired to respond to novel events in general, and as long as we keep cultivating them in our lives, we keep stimulating neuroplasticity and neurogenesis. New experiences not only lead to the growth of new brain tissue, they are linked to psychological wellbeing - there is a link between clinical depression and a lack of new cell growth in the brain, with the hippocampi of depressed patients sometimes shrinking by as much as 15%.
Whatever our age, we each have the ability to literally grow new brain tissue and guide the patterning of our neural nets in a way that supports our highest cognitive performance and lasting habits of health, happiness and longevity. The brain is designed to engage in constant neurogenesis, but you can stimulate this process by minimizing inflammation and oxidation, supporting blood flow to the brain, lowering your stress, and getting enough sleep. The healthier your neurons are, the more potential they have to develop a strong communication network with one another, a network that you can shape with your own intentions, choices and goals. Remember, it’s not just our nutrition & lifestyles but also the quality of our consciousness and the experiences we choose to have in each moment that create the structure of our brains, and thus our lives.