Neuroplasticity

Neuroplasticity is defined as the ability of the brain to change itself in response to environmental demands. The brain changes itself by breaking and making synaptic connections between neurons. Neuroplasticity can be observed on different scales. On the smallest scale, it takes the form of synaptic plasticity, which is the ability of the neuron to form new synaptic connections and break old ones. On the largest scale, neuroplasticity takes the form of cortical remapping, which is where one area of the brain takes over the function of another area of the brain. Synaptic plasticity depends on the activity of the neurons. If nearby neurons are regularly fired, a synaptic connection may gradually form. When two neurons with a synaptic connection are irregularly fired, then the connection may gradually fall apart. Maguire et al investigated the neuroplasticity of the brain in relation to natural settings.

A quasi-experiment was conducted that aimed to investigate how the brain structure of London taxi drivers differs from the average brain. The researchers used taxi drivers from London who had an average driving experience of about sixteen years. A control group comprising right-handed males who did not drive a taxi was also formed. MRI scans were conducted on all participants and were compared between the drivers and non-drivers. Researchers also correlated the number of years of taxi driving experience with the results of the MRI scans.

The results showed that taxi drivers had increased gray matter volume in the posterior hippocampus, compared to the control group subjects. Control subjects had increased gray matter volume in the anterior hippocampus. A correlation was also observed between the number of years of taxi driving experience and the volume of gray matter in the hippocampus, where the longer the participant drove a taxi, the more the volume of gray matter in the posterior hippocampus. The opposite was true for the anterior hippocampus. Based on these results, the study concluded that there is a redistribution of gray matter in the hippocampus, from the anterior to the posterior. This could have occurred because the posterior hippocampus is said to be involved in using previously learned spatial information, while the anterior hippocampus learns new spatial information.

Thus, from this study, we see how neuroplasticity occurs in the brain, as there was a redistribution of gray matter and new neural connections being formed in the areas of the brain that were used most frequently, and that this occurred because of certain changes in the environment of the London taxi, as they used the posterior hippocampus to reuse learned spatial information in order to transport their passengers.

Neural Pruning

Neuroplasticity is defined as the ability of the brain to change itself in response to genetics or environmental demands. The brain changes itself by breaking or forming synaptic connections between different neurons. A synapse is a connection that is formed between the dendrites of the cell body of a neuron and the axons of an adjacent neuron. Neural pruning is the process in which the synaptic connections between connected neurons fall apart. This occurs when connected neurons are rarely used or are irregularly fired, and the synaptic connection between these neurons is not required by the brain. Thus, neural pruning helps in the efficient conduction of impulses along with the nervous system, as it removes inefficient or unused connections, and allows neurons to form new connections with other adjacent neurons that are fired frequently. Draganski et al studied neural pruning in response to the behavior of learning.

An experiment was conducted that aimed to investigate whether structural changes in the brain would occur in response to practicing a simple juggling routine. The sample was randomly divided into two groups; jugglers and non-jugglers. Jugglers spent three months learning a simple juggling routine followed by three months where they were instructed to stop practicing. Participants in the control group never practiced juggling. Three brain scans were performed on each participant, one before the start of the experiment, one after three months, and the other after six months.

The results showed that there were no differences in the brain structure of the juggler and non-juggler participants before the start of the experiment. After three months, the jugglers had significantly more grey matter in the mid-temporal region of the area of the cortex in both hemispheres. These areas of the brain handle the coordination of movement. After six months, the differences decreased. However, the jugglers still had more grey matter than the non-jugglers. The study concluded that gray matter increases in response to environmental demands and shrinks in the absence of stimulation. This shows the cause-effect relationship between learning and brain structure.

Thus, this study shows how neural pruning occurs, as the gray matter had decreased after six months. The neural connections that had been previously formed had fallen apart, as they had not been used for the three months during which practice had stopped. These synaptic connections had been lost due to unuse, and neural pruning had occurred in these connections because these neurons were rarely fired.

Neural Networks

Neuroplasticity is defined as the ability of the brain to change itself in response to genetics or environmental demands. The brain changes itself by breaking or forming synaptic connections between different neurons. A synapse is a connection that is formed between the dendrites of the cell body of a neuron and the axons of an adjacent neuron. Neural networks are formations of neural connections that occur in response to a certain learning behavior. These connections are formed when certain neurons are constantly fired and frequently used in response to learning a certain behavior. This results in synaptic connections being formed between these neurons, and the neural network is formed. When neurons having synaptic connections are not fired regularly or are unused when a specific behavior is learned, their connections fall apart, and the neurons reform connections with other neurons that are being fired regularly during learning, and the neural network is further formed. Thus, neural networks are formed by both synaptic plasticity and neural pruning. A study that investigated the formation of neural networks in relation to the behavior of learning was conducted by Draganski et al.

An experiment was conducted that aimed to investigate whether structural changes in the brain would occur in response to practicing a simple juggling routine. The sample was randomly divided into two groups; jugglers and non-jugglers. Jugglers spent three months learning a simple juggling routine, followed by three months where they were instructed to stop practicing. Participants in the control group never practiced juggling. Three brain scans were performed on each participant, one before the start of the experiment, one after three months, and the other after six months.

The results showed that there were no differences in the brain structure of the juggler and non-juggler participants before the start of the experiment. After three months of the experiment, the jugglers had significantly more grey matter in the mid-temporal region of the area of the cortex in both hemispheres. These areas of the brain handle the coordination of movement. After six months, the differences decreased. However, the jugglers still had more grey matter than the non-jugglers. The study concluded that the grey matter in the brain grows in response to environmental demands and shrinks in the absence of stimulation. This shows the cause-effect relationship between learning and brain structure.

Thus, this study shows how neural networks are formed, as the grey matter had increased after 3 months in the region where coordination of movement occurs, and thus when the behavior of learning a juggling routine was learned, certain neural connections were formed in the region of learning this behavior of movement. Thus, the neural connections formed in the mid-temporal region resulted in the formation of a neural network.

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