Neuroplasticity

by Adrian Winship

  This study, along with others, deals with the different aspects of neuroplasticity in terms of aging. There is still a need for more research in order to interpret any neuroimaging data that reflects neuroplasticity in the brain, as well as the conditions and specific points in the aging process or a disease process when interventions must be done to induce neuroplasticity. Through these studies, we will be able to learn more about how we can apply neuroplasticity in our lives more effectively, and in a more scientific way.

  A Lifelong Process for Brain Development

  In the past few years, there have been some fundamental changes in how we understand the capacity of the human brain. New studies have provided us with a more positive view of the brain and its potential to develop and change throughout our lives.

  The brain is considered a highly dynamic system that's constantly reorganizing itself. It has the ability to be shaped and reshaped throughout our lives. Each of the experiences we have changes the organization of our brain at one level or another. This means that brain development is a lifelong process. Just because you have reached adulthood doesn't mean that your brain will stay the same until the day you die. Neuroplasticity is an incredible thing, and through it, we can keep on changing our lives for the better!

  Chapter 4: What Is Neurogenesis?

  Another interesting concept that's related to neuroplasticity is neurogenesis, which is the birth of new cells. Neurogenesis is a phenomenon that represents an important aspect of neuroplasticity, as well as other important brain processes like memory storage and learning. It's another fundamental discovery that is still being researched today.

  Neurogenesis is a fairly new concept that was only recently discovered. Back in the 1960s, Altman and Das were able to demonstrate neurogenesis in rats. But it was only in 1998 that the research team headed by Peter Eriksson discovered the phenomenon in human beings. Since then, other researches have shown that our brains have the ability to produce new cells even during adulthood, and that it's important for us to encourage this production.

  The new cells that are generated through neurogenesis fit into two broad categories. First, there are stem cells, which have an indefinite ability to replicate. Then there are progenitor cells, which are more limited in terms of their ability to divide and renew themselves compared to stem cells.

  Just like neuroplasticity, neurogenesis is also an important process. The importance of this phenomenon is clearly stated in a study about neurogenesis, cognition and cellular plasticity (Couillard- Després, et. al., Neurogenesis, cellular plasticity and cognition: the impact of stem cells in the adult and aging brain, 2011). When there is a continuous provision of new brain cells (neurons) arising from the neural stem cells of adults, this facilitates the execution of tasks that are dependent upon the hippocampus. This occurs because neurogenesis also reduces or blocks cognitive impairments. The study emphasizes the significance of memory and learning for the production of new neurons.

  If you want neurogenesis to occur in your brain throughout your life, you must keep on performing or engaging in activities that stimulate your brain. Learning new things doesn't only mean acquiring a new skill. It also means that your brain is getting new neurons. Whether you're learning a new language, learning how to play an instrument or performing any other activity that stimulates your mind, this encourages your brain to produce new cells. Therefore, you should always try to learn new things, no matter how old you get!

  Conversely, leading a sedentary lifestyle will have the opposite effect. This type of lifestyle doesn't just hinder neurogenesis, it also increases the risk of developing cognitive impairments. When your brain has a lot of activity, it doesn't cause damage to the neurons. Rather, damage is caused by inactivity, unhealthy eating habits, poor sleeping patterns, smoking, drinking alcohol and the like.

  Neurogenesis vs. Neuroplasticity

  To a lot of people, neurogenesis and neuroplasticity are the same thing. But this isn't necessarily true. Simply put, neurogenesis occurs when new neurons are created, and neuroplasticity occurs when new connections are formed. Neuroplasticity may occur if the new neurons created through neurogenesis are put to good use.

  In other words, neurogenesis is the “birth” of new neurons, while neuroplasticity is the ability of the brain to adapt and change as a response to stimuli. Even though your brain is aging, it continues to develop through neurogenesis and change through neuroplasticity. One thing these two processes have in common is that they challenge the past beliefs that our brains don't change once we reach adulthood.

  Although neuroplasticity and neurogenesis are two different processes, they work together in a synergistic way. For instance, throughout adulthood, new neurons are created in the different parts of your brain, and these contribute to your learning. And as you learn, new synapses are created between neurons.

  Ideally, neurons should always be in a constant state of equilibrium. This means that as soon as neurons in the brain die, they should be replenished. But the generation or production rate of neurons depends on several factors, such as stress level, age, diet, neural activity, whether neurotoxins are present or not and more.

  These two processes can be used for the treatment of brain injuries whether taken together or individually. Through the application or enhancement of neuroplasticity, the survival of the neuronal cells is ensured and compensated for through the reorganization of the brain and the rewiring of these cells. At the same time, neurogenesis can be utilized alongside neuroplasticity to regenerate or replace neuronal cells in a brain that have incurred damage or injury.

  Where Does Neurogenesis Occur?

  Neurogenesis occurs in the lower part of the brain's lateral ventricles, or the subventricular zone. But it is more evident in the hippocampus dentate gyrus subgranular zone. This is a structure that's located in the brain's temporal lobe, and is considered to be part of the limbic system. Some of the main functions of the hippocampus include memory, spatial orientation, emotional regulation, and learning.

  Nowadays, there's widespread acceptance of the fact that, for adults, neurogenesis occurs in these parts of the brain. Also, the process occurs at a frantic rate, which means that there are a lot of new cells being born each day. Normally though, about half of these cells end up dying in a matter of one to two months. The brain cells that are born in the subventricular zone are transmitted to the olfactory bulb, but those that are born in the dentate gyrus are meant for the hippocampus.

  In adults, neurogenesis may occur in the other parts of the brain as well. However, there isn't enough evidence yet to support this fact. There has been recent research that has shown that there are small, inhibitory, non-pyramidal interneurons that are being born both in the striatum and cortex. These interneurons create and secrete GABA, and may help in the regulation of larger kinds of neurons that create long-distance connections between the various regions of the brain.

  How Neurogenesis and Neuroplasticity Work Together

  For more than a decade now, neuroscientists have been trying to find out how neuroplasticity and neurogenesis work together to change how we think, behave and remember.

  One particular study conducted at the University of Alabama at Birmingham discovered how neurogenesis and neuroplasticity work together (Adlaf, et.al., Adult-born neurons modify excitatory synaptic transmission to existing neurons, 2017). Through this study, the researchers discovered that neurogenesis and neuroplasticity work together by causing older, less-fit neurons to die off as the newborn neurons take over the existing circuits of the brain, creating healthier synaptic connections.

  For this study, their focus was on adult neurogenesis that occurs in the hippocampus dentate gyrus. This part of the brain is the epicenter of the process, and is responsible for the creation of new memories, as well as the natural exploration of new environments and more. Specifically, the study focused on the newborn granule cell neurons found in the dentate gyrus, which should first get wired into a neural network through
the formation of synapses (neuroplasticity) so as to stay alive and take part in the continuous function of the neural circuits.

  As aforementioned, there are two main regions in the brain that can constantly produce new neurons through neurogenesis. The first is the spatial and long-term memory hub, or the hippocampus, and second is the muscle and coordination memory hub, or the cerebellum. Both of these parts of the brain contain a lot of granule cells that, incidentally, have the highest neurogenesis rate.

  One of the most important parts of neuroplasticity is known as "neural pruning," or “neural Darwinism.” As it turns out, neurons aren't “fired and wired” together into a network that can be extinguished. Instead, the UAB study suggests that the new neurons can help expedite the neurogenesis process through a "survival of the fittest" battle.

  When neuroplasticity and neurogenesis work together, this allows the brain to create new paths for thoughts to travel on. his means that it's entirely possible to reinvent yourself completely, or even overcome past events that may evoke feelings of stress and anxiety. This allows you to live your life to the fullest.

  How to Increase Neurogenesis

  Neurogenesis is the process wherein new neurons are created or born in the brain. This process can reduce depression and anxiety, and improve memory. We've discussed how neurogenesis can work together with neuroplasticity to help you change your life for the better. Later, we'll talk about some ways to enhance neuroplasticity. Of course, it's also worth knowing how you can increase neurogenesis in your brain. Here are some tips:

  ● Exercising regularly

  This is one of the most effective ways for you to increase neurogenesis. Exercise improves your memory and stimulates both GDNF and BDNF. Also, regular physical activity may increase the survival rate of newborn neurons, as well as the proliferation level of progenitor cells.

  ● Getting enough sunlight

  When you get enough sunlight, this increases BDNF. Also, bright light has the potential to induce neurogenesis and lower both depression and anxiety.

  ● Sleeping well

  Although the effect of sleep disruption in the inhibition of neurogenesis isn't completely understood yet, sleeping well seems to be extremely essential. When you experience sleep disturbances, this has a significant adverse effect on the proliferation of cells, and on neurogenesis as well. After experiencing chronic sleep deprivation, it takes about two weeks for adult neurogenesis to get back to normal levels. This is especially dangerous when you're also suffering from other brain issues.

  ● Having frequent sex

  Frequent sexual experiences may increase the proliferation of cells in the dentate gyrus, as shown in a study on adult male rats (Leuner, et. al., Sexual Experience Promotes Adult Neurogenesis in the Hippocampus Despite an Initial Elevation in Stress Hormones, 2010). In the same study, the researchers found out that frequent sexual experiences promote neurogenesis, enhance proliferation of cells and increase the number of dendritic spines of the dentate gyrus of rats without increasing the levels of stress hormones.

  ● Getting enough DHA

  This is a type of essential omega-3 fatty acid that is found in the body. You should get enough DHA, as it helps in the repair of cognitive decline, and is essential for the health of the brain, both of which are important for neurogenesis.

  ● Avoiding sugar

  Because of the deleterious effect of sugar on the metabolism of glucose, it may have an adverse effect on neurogenesis. Raw vegetables and fruits may modulate the effect of sugar, so it's recommended to only consume sugar with foods that are rich in polyphenols and flavonoids.

  ● Restricting calories and intermittent fasting

  When you restrict calories, this helps increase the expression of GDNF, BDNF and other nerve growth factors both in the basal ganglia and the hippocampus. Fasting has the same effect, and it also keeps the brain protected from oxidative injury and stress.

  Aside from these, there are other ways to increase neurogenesis as well. The bottom line is that you must keep your brain healthy if you want to promote neurogenesis, which, in turn, leads to neuroplasticity.

  Chapter 5: Why Your Environment Matters

  The brain is an extraordinarily complex structure that always has something to teach us. As time goes by and scientists study the human brain, they keep learning new things that shatter our previous beliefs. One such discovery was neuroplasticity, which challenged what we believed in the past about how the brain stays relatively the same as soon as we grow into adults.

  Of course, neuroplasticity isn't a new concept. But it is interesting to think about how our brains are able to change as a response to experiences, learning and environmental stimuli. This process isn't just a by-product of evolution, it has been occurring in us even when we weren't aware of it. Neuroplasticity happens both in the brains of children and in the brains of adults.

  Our brains contain more than a billion neurons, which are interconnected by synapses. Neuroplasticity occurs when there are changes in the wiring of our brains. The strength of these connections between the neurons is modified according to what we experience, recall, think and learn. This type of neuroplasticity occurs as new synapses are either added or eliminated from our brain.

  Apart from our own thoughts and actions, another factor that has an effect on neuroplasticity is our environment. Remember that the changes in our brains may occur as a response to environmental stimuli. Environmental enrichment is important when it comes to this phenomenon. Each of us grows and develops in different ways depending on what environment we live and interact with other people in. So if you want to improve your neuroplasticity, you may want to look into enriching your environment for the benefit of your brain. In order to improve your life, looking for a better environment may be the answer. In this chapter, we'll learn more about environmental enrichment and how you can use this to improve your brain's neuroplasticity.

  What Is Environmental Enrichment?

  Environmental enrichment refers to the stimulation of the human brain by its social and physical surroundings. The brains of those who are in more stimulating environments are most likely to experience neuroplasticity, along with dendrite arbors that are more complex and in turn lead to an increase in brain activity.

  This effect primarily occurs during the development of the brain, but it also occurs during adulthood. When more synapses are created, there will also be an increase in synaptic activity, which leads to an increase in the number and size of energy-support glial cells. Environmental enrichment may also enhance the process of capillary vasculature, which provides the glial cells and neurons with more energy. With all these things happening, environmental enrichment may also result in an increased neurogenesis rate.

  Several studies have suggested that when people don't get enough stimulation from their environments, this may impair and delay their cognitive development. Also, acquiring and engaging in higher education levels and environments that are more cognitively stimulating and challenging allows people to have a greater cognitive reserve.

  There are some important components of environmental enrichment you may want to consider. Some of these are quite robust, and may have a specific influence on hippocampal behavior and neuroplasticity:

  ● Physical activity

  This aspect of environmental enrichment is one that has been the focus of several studies and research. In one such study, the researchers explored the various aspects of environmental enrichment by dividing the animals into different conditions (van Praag, et. al., Running increases cell proliferation and neurogenesis in the adult mouse dentate gyrus, 1999). The researchers used bromodeoxyuridine or BrdU as their marker for dividing the cells. Through the study, they found that just placing a running wheel inside the cages was enough to induce the proliferation of cells in the dentate gyrus.

  The researchers also discovered an increase in the number of BrdU-positive neurons both in the runner and enriched groups. This showed that physical activity
improved the proliferation as well as the survival of newborn neurons. Other studies (van Praag, et. al., Neural consequences of environmental enrichment, 2000; van Praag, et. al., Functional neurogenesis in the adult hippocampus, 2002) also support the fact that physical activity may positively impact neurogenesis, especially in the hippocampus.

  ● Spatial exploration

  In addition to physical activity affecting neuroplasticity, when people are exposed to enriched environments, it may also improve their memory and neurogenesis. In one specific study (Freund, et. al., Emergence of individuality in genetically identical mice, 2013), researchers discovered that a vital component of an enriched environment is that spatial exploration that happens when animals live in such environments.

  Using exploratory behavior as their measure, the researchers discovered that the mice that distributed their spatial coverage randomly over the whole environment experienced an increase in neurogenesis compared to mice that had a smaller and more stable spatial coverage. This showed how important spatial exploration is as a component of an enriched environment.

  ● Other components

  Another component of enriched environments is the different types of learning that are associated with the hippocampus. One particular study showed that these different types of learning may promote neurogenesis in the hippocampus in animals (Gould, et. al., Learning enhances adult neurogenesis in the hippocampal formation, 1999). Of course, since this study was conducted on animals, it wasn’t able to isolate the kind of learning that occurred and contributed to neurogenesis.