When I was growing up the general thought was that you had a finite number of brain cells and once, they died, that was it, there was no hope for your brain to regenerate. But in the last decade, research has found those old ideas are simply incorrect. There is real hope that there are many things that we can do to create a healthier brain, even if we have made poor choices earlier in life. So, how does that work? Through something called Neuroplasticity. Neuro-plas-ti-city
Neuroplasticity is the lifelong ability of the brain to create new neural pathways based on new experiences. Contrary to previous assumptions, in recent years, neuroscientists have discovered that the human brain continues to have the ability to create new neural pathways into adulthood. Below are some highlights about how neuroplasticity works in the brain.
When does neuroplasticity occur in the brain?
At the beginning of life: when the immature brain organizes itself.
In case of brain injury: to compensate for lost functions or maximize remaining functions.
Throughout adulthood: whenever something new is learned and memorized
Neuroplasticity has a clear age-dependent determinant.
Although plasticity occurs over an individual’s lifetime, different types of plasticity dominate during certain periods of one’s life and are less prevalent during other periods.
Neuroplasticity occurs in the brain under two primary conditions:
During normal brain development when the immature brain first begins to process sensory information through adulthood (developmental plasticity and plasticity of learning and memory).
As an adaptive mechanism to compensate for lost function and/or to maximize remaining functions in the event of a brain injury.
The environment plays a key role in influencing plasticity.
In addition to genetic factors, the brain is shaped by the characteristics of a person's environment and by the actions of that same person.
Another factor that impacts brain regeneration is neurogenesis. Neurogenesis is the birth of new neuronal cells. Recent research demonstrates that neurogenesis continues into and throughout adult life. Ongoing neurogenesis is thought to be an important mechanism in neuronal plasticity. New techniques will be able to direct neurogenesis in other areas of the brain. This would enable the brain to repair damage and enhance mental functioning.
New neurons in the human brain have been found in the ventricles of the forebrain as well as the hippocampus. The cells that become neurons travel to the olfactory bulbs. Researchers have speculated that neurogenesis occurs in the hippocampus since this area is so important in memory and learning. Other researchers have attempted to discover if neurogenesis occurs in other areas of the brain and spinal cord but have not yet found conclusive evidence to support this hypothesis.
There are several factors that impact neurogenesis, including physical activity, environmental conditions and even hormones/neurotransmitters. Here is a brief explanation of these factors and how they affect neurogenesis.
Has been shown to affect proliferation and survival of neurons.
Increase neurogenesis and neuronal survival has been shown in crayfish raised in an enriched environment when compared to siblings raised in an impoverished environment.
Estradial and testosterone have been shown to influence the rate of neurogenesis.
Serotonin was found to affect the survival of neurons. Serotonin helps to synaptic connections in the cortex and hippocampus.
Lack of serotonin in the hippocampus has been associated with such disorders such as depression, schizophrenia and Alzheimer’s disease.
So, why would regular exercise, being in an enriched environment (physically nourishing and mentally stimulating) and the presence (or absence) of certain neurotransmitters impact the brains’ ability to generate new cells?
In his book “The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science”, Norman Doidge discusses the case of a surgeon in his 50’s who suffered a stroke. The surgeon’s left arm was left paralyzed. During his rehabilitation, his good arm and hand were immobilized, and the doctor is set to cleaning tables. The task is at first impossible. Then slowly the bad arm remembers how to move. He learns to write again; and then to play tennis. The functions of the brain areas killed in the stroke ultimately transfer themselves to healthy regions!
His brain eventually compensates for the damaged areas by reorganizing and forming new connections between intact neurons. In order to reconnect, the neurons need to be stimulated through activity. The use of activity is one of the most important directions that therapeutic intervention for brain injury has ventured in the past decade. As horrible as the wars in Iraq and Afghanistan have been, one of the positive outcomes is the discovery of using activity as a therapeutic tool to recover from traumatic brain injury.
If you would like to learn more about neuroplasticity, here is a link to a fascinating video on neuroplasticity and how different conditions can affect neural pathways. What do you think about the prospects of neuroplasticity and what this means in terms of what we once thought about the death of brain cells?
By Lisa Tobler, LMFT
Lisa Tobler, LMFT passion is in helping people recover from traumatic events. She has advanced training in EMDR (Eye Movement Desensitization Reprocessing) to treat trauma and EFT (Emotion Focused Therapy) to assist couples to heal their relationship.