Neurogenesis
Neurogenesis is the creation of new neurons through stem cells in the human brain which occurs throughout life. This is also a new discovery and until recently most believed that neural stem cells didn't occur in adult human brains. The regulation of these stem cells occurs through molecules called growth factors.
Depression is assosciated with reduced neurogenesis. Anti-depressants boost neurogenesis by elevating levels of brain-derived neurotrophic factor (BDNF), as does exercise which is a natural anti-depressant. However, BDNF can also be increased by changing your living conditions. In experiments where mice were placed in an 'enriched' environment it was found that these same mice had notable improvements in memory tasks such as navigating through a maze. They also experienced elevated mood. The environments they were placed in consisted of larger cages, many toys and also, a running wheel. Mice which previously had learning difficulties but were then placed in this enriched environment were later found to perform just as well as mice of average ability when it came to memory tasks. The more stimulating environment also reduces the decline of memory that occurs with aging.
In another experiment, mice with a genetic predisposition for Huntingdon's disease were divided into two groups. One group was placed in the enriched environment mentioned above and the others in a normal environment (small cage, no toys, no running wheel). The mice which were placed in the enriched environment began developing symptoms much later than the other mice, indicating that environment and experience can delay the onset of this disease. Similar results were found with both Alzheimer's disease and dementia.
This part of the post is about recovering from strokes and delaying mental illnesses such as dementia and Alzheimer's disease.
In a test to deduce the effects of high and low levels of brain atrophy (shrinkage) in older individuals it was found that the regions of the brains of those individuals with high atrophy differed in activity to the brain regions activated by the low atrophy individuals when both groups were carrying out the same memory-orientated tasks. The fact that performance between both groups was relatively similar yet each group used different brain regions to perform the same task means that the brain is capable of network compensation. This means that when an area of the brain that is typically assosciated with a certain function becomes atrophied or no longer works, alternative brain regions will take on its function.
In humans, physical exercise has been shown to delay the onset of dementia and brain training (mental exercise) has been shown to reduce the effects of Alzheimer's disease.
According to Dr. Michael Valenzuela (an expert on mental decline with aging), there are three effective methods for improving brain function and slowing age-related mental decline. He calls these three methods the "Cognitive Key", "Social Key" and the "Physical Key".
The cognitive key involves learning something new, problem solving or improving memory. It is important that this key be challenging in order to produce more benefits. An example of a cognitive challenge could be learning a language or trying to remember as much of your day before going to sleep.
The social key is self-explanatory, as humans are social creatures the benefits of social interaction are numerous. Socialising promotes better cognitive functioning and elevates mood as well.
The physical key consists of some type of physical exercise or skill practice. Physical activity which is done with friends or in a group is particularly beneficial as it combines both the social and physical elements.
Some examples of beneficial activities are: travelling, learning a martial art, social shopping and also dancing. These activities are all typically done in groups and involve more than one of each key method.
Network compensation is crucial for many stroke victims who wish to recover functionality of the brain.
Sunday, 2 June 2013
Synaptogenesis
Neuroplasticity refers to the brain's ability to remould and restructure itself in response to internal and external environments. In this respect it has similarities with epigenetics and this is one of the ways that neuroplasticity works. The idea that the adult brain can change after childhood development is a relatively new concept in science. Until very recently most scientists believed that it didn't occur to a large extent, if any at all. However, it has been proven to occur through brain scans of patients undergoing psychotherapy and also after undertaking meditation exercises regularly for a couple of months (which is how I came to find out about it). While I'll be focusing on the positive aspects of neuroplasticity it is important to note that it can have negative consequences as well. For example, if you continually think that you are incapable of performing a certain action you will start to believe it and it will cause limitation in your life.
How neuroplasticity works is by changes in connections between nerve cells in the brain. Nerve cells (or neurons) form connections with each other depending on the timing of their impulse firing. If two close neurons fire simultaneously they will be naturally inclined to link together and form a connection. The three ways of explaining this process are the following: "Neurons that fire together, wire together", and "Neurons that are out of sync, fail to link" (so if two neurons are not simultaneously excited, they will not become more assosciated with each other). Neurons will connect with each other due to the expression of their genes. This is where epigenetics come in, when certain genes are activated by internal or external environments they will change their expression and guide the axons (nerve fibres that extend from the cell body of nerve cells) towards other neurons. The good thing about neuroplasticity is that we aren't required to experience some profound event in order to change our brains, just thinking differently causes our brains to form different connections between its nerve cells.
One of the foundational principles of neuroplasticity is that you either "use or lose" various connections. As the brain is constantly adapting to its environment it is also constantly breaking old connections and forming new connections. It is estimated that we have 100 billion nerve cells in our brains and each is capable of making 10,000 connections with other nerve cells. With so many potential connections that can be formed, the possibilities of brain plasticity are vast.
Nerve cells form connections at structures called synapses. At synapses, nerve cells release specific molecules called neurotransmitters. Due to the effect of experiences on reforming these synaptic connections even identical twins will have different brain structures.
Pathways of nerve cells are defined by the strength of the synaptic connections, these connections become stronger each time they are used, similar to how muscles are affected by working out at the gym. It is believed that we are forming and recreating 1 million synaptic connections each second.
It is worth noting that although neuroplasticity is slowed by aging, it isn't stopped. Neuroplasticity occurs in your brain throughout your entire life. The above information refers to synaptogenesis, i.e. the creation of new synaptic connections between neurons.
However, neuroplasticity occurs in another recently discovered way; neurogenesis.
How neuroplasticity works is by changes in connections between nerve cells in the brain. Nerve cells (or neurons) form connections with each other depending on the timing of their impulse firing. If two close neurons fire simultaneously they will be naturally inclined to link together and form a connection. The three ways of explaining this process are the following: "Neurons that fire together, wire together", and "Neurons that are out of sync, fail to link" (so if two neurons are not simultaneously excited, they will not become more assosciated with each other). Neurons will connect with each other due to the expression of their genes. This is where epigenetics come in, when certain genes are activated by internal or external environments they will change their expression and guide the axons (nerve fibres that extend from the cell body of nerve cells) towards other neurons. The good thing about neuroplasticity is that we aren't required to experience some profound event in order to change our brains, just thinking differently causes our brains to form different connections between its nerve cells.
One of the foundational principles of neuroplasticity is that you either "use or lose" various connections. As the brain is constantly adapting to its environment it is also constantly breaking old connections and forming new connections. It is estimated that we have 100 billion nerve cells in our brains and each is capable of making 10,000 connections with other nerve cells. With so many potential connections that can be formed, the possibilities of brain plasticity are vast.
Nerve cells form connections at structures called synapses. At synapses, nerve cells release specific molecules called neurotransmitters. Due to the effect of experiences on reforming these synaptic connections even identical twins will have different brain structures.
Pathways of nerve cells are defined by the strength of the synaptic connections, these connections become stronger each time they are used, similar to how muscles are affected by working out at the gym. It is believed that we are forming and recreating 1 million synaptic connections each second.
It is worth noting that although neuroplasticity is slowed by aging, it isn't stopped. Neuroplasticity occurs in your brain throughout your entire life. The above information refers to synaptogenesis, i.e. the creation of new synaptic connections between neurons.
However, neuroplasticity occurs in another recently discovered way; neurogenesis.
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