Neuroplasticity is the brain's amazing capacity to change and adapt. It refers to the physiological changes in the brain that happen as the result of our interactions with our environment. From the time the brain begins to develop in utero until the day we die, the connections among the cells in our brains reorganize in response to our changing needs. This dynamic process allows us to learn from and adapt to different experiences.

A growing number of research publications have illustrated the remarkable ability of the brain to reorganize itself in response to various sensory experiences. A traditional view of this plastic nature of the brain is that it is predominantly limited to short epochs during early development. Although examples showing that neuroplasticity exists outside of these finite time-windows have existed for some time, it is only recently that we have started to develop a fuller understanding of the different regulators that modulate and underlie plasticity.

By the 20th century, genetics was widely accepted as the basis of human characteristics, displacing John Locke’s 17th-century notion of the “tabula rasa,” which suggested that the mind started as a blank slate from which our competencies, including intelligence and personality, were developed. Locke and others argued that the environment indelibly etched its signature on each individual. The resulting “nature versus nurture” binary dispute is collapsing today under the weight of a mounting body of evidence. Yes, we enter the world with some brain physiology already set, but each brain is reshaped into its own unique configuration.

We know that the neurons communicate with each other using electrochemical signals. These signals are transmitted through a structure in the neuron called the synapse. Stimulating the neural pathways through a repetitive, memory-forming cognitive function (such as studying or practicing) strengthens the synaptic communication between neurons. Additionally, the brain has the ability to create new synapses. While neuroplasticity can occur naturally as we undergo different experiences, changes in the brain can also be activated through neuroplasticity exercises and cognitive training.

Neuroplasticity would not be possible without the malleable traits of neurons. Neurons are what cause the brain to change and the entire body to function effectively. Neurons are the longest-living cells in our bodies and are responsible for carrying information throughout the brain and then on to the muscles and organs of the body.

There are four main types of neuroplasticity adaptations:

Synaptogenesis: Synaptogenesis is the creation of new neural connections. Synaptogenesis occurs when the brain is exposed to new environments and experiences in activities such as traveling or learning a new musical instrument.

Neurogenesis: Neurogenesis is the creation of new neurons in central parts of the brain, the hippocampus and olfactory bulb. Neurogenesis occurs at high rates in the young brain and can occur in the adult brain until around the tenth decade of life.

Long-term depression: Long-term depression is the weakening of synapses that aren’t being used. Long-term depression is associated with memory and motor learning. Neuroplasticity research has studied long-term depression’s role in memory loss from neurological disorders such as Alzheimer’s Disease.

Long-term potentiation: Long-term potentiation is the strengthening of synapses through recurring activities like studying or practicing. Long-term potentiation is associated with learning and memory.

How can we build and maintain those connections that are relevant during early childhood and even later into adulthood? Neuroplasticity involves a “fire together, wire together” principle: as described at Brighter Health, if certain neurons keep firing at the same time, eventually they’ll develop a physical connection and become physically associated. This experience-dependent plasticity means if you practice something consistently, such as meditating, exercising or learning how to play an instrument, you’re likely to alter your brain to associate the relevant parts of its structure. Whether you are a child, adolescent or older adult, actions and thoughts (both positive and negative) that you repeat can form new neural pathways.

One aspect of plasticity is neurogenesis. This is when new neurons are born from stem cells within the brain, which can then form new circuits. Neurogenesis surprisingly only happens in a few areas in the brain. One area is the hippocampus which needs a lot of new neurons because it encodes new memories. Another area is the olfactory bulb, which allows us to sense smells.

Contrast this with the prefrontal cortex. Sitting at the front of your brain, the prefrontal cortex is what performs high level abstraction and ‘smart’ thinking. Interestingly, the prefrontal cortex is not capable of neurogenesis. Essentially from an evolutionary standpoint, the brain figured it is as smart as it needs to be, but there will be many important new smells to identify!

There is an operation called a hemispherectomy which baffles neuroscientists even today. It’s needed in life-threatening conditions such as severe epilepsy, where literally half of a person’s brain has to be cut out. In theory, this should be devastating because each half of the brain manages very different functions, such as controlling one side of the body. However, up until teenage years, when half of the brain is removed, the other half has the capability to rewire itself into a whole new left-right brain.

Within the last four decades, our view of the mature vertebrate brain has changed significantly. Today it is generally accepted that the adult brain is far from being fixed. A number of factors such as stress, adrenal and gonadal hormones, neurotransmitters, growth factors, certain drugs, environmental stimulation, learning, and aging change neuronal structures and functions. The processes that these factors may induce are morphological alterations in brain areas, changes in neuron morphology, network alterations including changes in neuronal connectivity, the generation of new neurons (neurogenesis), and neurobiochemical changes.