Our brains are incredibly complex organs that continually adapt to our experiences and the environment around us. One of these complexities is the neurons. Our brain is made up of neurons that connect with one another to form a wide network. This network aka ‘neural network’ transfers information from different parts of our body to the brain.
A synapse is a connection between two neurons and these synapses allow information to travel between neurons. When these synapses are eliminated or no longer used by the brain, it is termed Synaptic pruning.
It is a natural process that occurs in our brains throughout our lives, but it is particularly active during early childhood and adolescence. In this article, we will explore the basics of synaptic pruning, how it works, and provide examples of its impact on brain development.
What is synaptic pruning?
Synaptic pruning is a self-imposed process of eliminating weaker connections between neurons in the brain. This is done by the brain itself and involves the selective removal of synapses that are not frequently used with time, allowing the strengthening of essential connections. This process is critical to shaping the architecture of the brain, allowing for more efficient and effective neural communication.
Recent studies have revealed that the brain is a more moldable organ than previously thought. This characteristic of the brain is visible as the period of synaptic pruning begins in early childhood and continues throughout adolescence, leading to a significant reduction in the number of synapses in the brain by adulthood.
How does synaptic pruning work?
The brain of an infant is the most powerful brain which produces a million neural connections as it grows. Synaptogenesis is a process where a child’s brain experiences an explosion of neural connections. This results in the formation of many connections that may be no longer triggered by the child throughout the growing period.
This rapid period of synaptogenesis plays a vital role in learning, memory formation, and adaptation early in life. At about 2 to 3 years of age, the number of synapses hits a peak level. But then shortly after this period of synaptic growth, the brain starts to remove synapses that it no longer needs.
The synapses that are frequently used will be strengthened, while those that are not used will be weakened or eliminated. Hebb’s law puts it all together which states that "neurons that fire together wire together”. Synaptic pruning is the process by which this elimination occurs.
Synaptic pruning is majorly influenced by experiences and environmental factors. The connections between neurons that are used more frequently are strengthened, while those that are used less frequently are weakened or eliminated. This process allows the brain to adapt to its environment and make connections that are necessary for survival.
Facts on Early Brain development and Synaptic Pruning
An infant is born with 86 trillion neurons in the brain almost the same as that of an adult. It's a fact that the brain of an infant is only 25% of the brain of an adult. A child's brain while growing is influenced by experiences and surroundings but the number of neurons it will have will be determined by the genetic attributes. Since the human brain cannot produce new neurons, it can only retain the number of neurons at the time of birth.
Early brain development is often linked to synaptic connections. A child's brain is capable of producing a tremendous amount of connections as much as 1000 trillion by age 3, which is double the connection compared to the brain of an average person.
Given this fact many researchers and child education experts believe that early education is the defining factor in the child brain development. When the early synaptic connections are formed by interactive learning, activities, and systematic education then brain wiring happens in the correct way.
How neural networks are eliminated?
Glial cells, which are non-neuronal cells in the brain, play a vital role in synaptic pruning. These cells help to identify synapses that are not being used frequently and facilitate their removal. Microglia, a type of glial cell, plays a particularly important role in synaptic pruning. They are responsible for engulfing and removing inactive synapses, allowing for more efficient neural communication.
Examples of synaptic pruning in action
Synaptic pruning has been observed in many different areas of the brain, and its effects can be seen in a range of behaviors and abilities.
Research has shown that synaptic pruning is particularly active in the areas of the brain that are involved in language acquisition. As children learn the language, the connections between neurons that are necessary for communication are strengthened, while those that are not used are eliminated.
This process allows children to develop more efficient and effective language skills.
For instance, you may have learned a new language in childhood and you would have become fluent in it. Over the years, if you’ve reduced speaking that language or studying works related to that language, the result will be that you must have forgotten completely or partially the ABCs of that language. That’s synaptic pruning at work.
Synaptic pruning also plays a critical role in motor development. As children learn to move and coordinate their bodies, the connections between neurons that are necessary for movement are strengthened, while those that are not used are eliminated. This process allows for the development of more efficient and precise motor skills.
Synaptic pruning is particularly active during adolescence, leading to changes in behavior and cognitive abilities. During this stage, the connections between neurons that are necessary for social and emotional development are strengthened, while those that are not used are eliminated. This process allows for the development of more mature and sophisticated social and emotional skills.
Synaptic pruning is a critical process in brain development that allows for the strengthening of essential connections and the elimination of those that are not necessary. This process is influenced by experiences and environmental factors, allowing the brain to adapt to its surroundings and make connections that are necessary for survival.
At what age does synaptic pruning start?
Although synaptic pruning occurs throughout our life, it starts in early childhood - when a child is 8 months old - peaks at adolescence, and continues through adulthood.
What is synaptic pruning also called?
Synaptic pruning in medical sciences is also referred to as neural pruning
Is synaptic pruning necessary?
Since synaptic pruning is not a forced process but rather a natural one, we cannot control it but use it to our advantage. Various methods of brain education adopted in early childhood ensure healthy brain growth and retention of neural cells.