What Are Neurons?

Recent research unlocked the knowledge that we are actually not born with all of the neurons we will ever have. We might build new ones as children to help establish neural circuits. These circuits act as information highways between the various areas of the brain. Scientists also believed that once a neural circuit was established, any additional neurons would disrupt the flow of information and disable the brain’s communication system. Let’s look more into the question of “What are neurons?” and why they matter.

Joseph Altman challenged this belief in 1962 and cited evidence of neurogenesis, (new neurons being created) in the hippocampus. These neurons later migrated to other parts of the brain. Michael Kaplan confirmed Altman’s findings in 1979 and in 1983, he found neural precursor cells in the forebrain of an adult monkey. 

Later, Fernando Nottlebohm showed that the number of neurons increased during mating season in male canaries. This prompted him to further research. After all, if new ones were possible in canaries, why wouldn’t they be possible in humans? Other scientists figured these findings could only apply to mammals. Fred Gage and Peter Eriksson later showed that the human brain produces new ones. However, some scientists believe neurogenesis is an unproven theory. Others think compelling evidence suggests a link between adult-generated neurons and learning and memory. 

Did You Know? 

Supplements, such as Nerve Control 911 can help your overall nervous system. 

The Architecture of the Them

The central nervous system includes the brain and the spinal cord and it is made up of two basic cell types: neurons and glia. Glia outnumber neurons in some parts of the brain, but neurons are more important. 

Neurons are the messengers within the brain. Using electrical impulses and chemical signals, they transmit information between different areas of the brain and the nervous system. Everything we think, feel, or do would disappear without the work of them. Essentially, without neurons, existence wouldn’t exist. 

Neurons have three basic parts: the cell body and two extensions called an axon and a dendrite. Within the cell body, there is a nucleus that controls the cell’s genetic material. The axon looks like a long tail and transmits messages from the cell. Dendrites look like the branches of a tree and receive messages from the cell. They communicate with each other by sending chemicals known as neurotransmitters across the synapse between the axons and dendrites of adjacent ones.

1. Sensory neurons carry information from the sense organs (such as the eyes and ears to the brain). 
2. Motor neurons control voluntary muscle activity, such as speaking and they carry messages from nerve cells in the brain to the muscles.
3. All the other neurons are called interneurons. 

Scientists believe that neurons are the most diverse kind of cell in the body. Within these classes are hundreds of different types, each with specific message carrying abilities. How they communicate with each other is what makes us think, feel, and act. 

The Birth of Neurons 

Scientists debate the extent of which neurons are born in the brain. The majority of them are already present in the brain when we are born, but there is evidence to suggest neurogenesis is a lifelong process. Neurons are born in areas of the brain that have rich deposits of neural precursor cells known as neural stem cells. These cells have the potential to generate nearly all of them and gila found in the brain. 

Neuroscientists have only observed how neurons behave in a laboratory setting. Though it is likely that they behave similarly in the brain, it is not proven. Even without proof neurons act the same in the brain as in a laboratory setting, the laboratory evidence gives us some indication of their overall behavior. This science is still emerging and can change as we discover more about the biology of them. 

Neural stem cells increase with mitosis and produce either two new stem cells or two early progenitor cells. If a stem cell divides to produce another stem cell, they are said to self-renew. The new cell has the potential to make more stem cells. 

When a stem cell divides and produces an early progenitor cell, they differentiate. Differentiation means a new cell is more specialized in its form and function. An early progenitor cell is said to differentiate. Differentiation means the new cell is more specialized in form and function. Early progenitor cells do not have the potential of a stem cell to make different types of cells. It can only make cells in its lineage. Early progenitor cells can self-renew or go in either creating astrocytes or producing neurons or oligodendrocytes. 

Migration 

After creating a neuron, it has to travel to the brain to complete its work. But how does a neuron know where to go and what helps it along its journey? Scientists have noticed that they have two different ways to travel. 

Neurons can either migrate along the fibers of cells called radial glia. Radial glia extend from the inner to the outer layers of the brain. They glide along these fibers until they reach their destination. 

Neurons can also travel by using chemical signals. Scientists have found molecules on the surface of neurons known as adhesion molecules that bind with similar molecules on nearby glial cells or nerve axons. These chemicals can guide the neuron to its final location in the brain. 

Not all neurons make it to the brain and scientists believe only a third reach their destination. Some cells die during development. Other neurons survive the trip but they wind up in a destination they shouldn’t be. Mutations in genes that control migration can create areas of misplaced or oddly formed them can cause disorders such as childhood epilepsy. Some researchers also suspect schizophrenia and dyslexia are a result of misguided neurons. 

Differentiation

Once a neuron reaches the brain, it has to work. This process is known as differentiation and it is the final step of neurogenesis. They are responsible for the transport and uptake of neurotransmitters, relaying information between brain cells. As a new one settles in, it begins to resemble surrounding cells and develops an axon and the dendrites communicate with its neighbors. 

Death

They are the longest living cells in the body and large numbers die during migration and differentiation. The lives of them can also take weird turns and have unnatural deaths that cause certain diseases of the brain. In Parkinson’s disease, neurons that produce neurotransmitter dopamine die in the basal ganglia, which is an area that controls body movements. 

Bottom Line 

Scientists hope they are starting to understand more about the life and death of neurons. From their further understanding, they can develop new treatments and potential cures for brain diseases and disorders.