Intro to The Brain

• What is a neuron?

• What do neurons look like?

• How do neurons work?

• What is the role of neurotransmitters in our brains?

What is a neuron?

A neuron is a nerve cell in the brain.

At birth the brain weighs about one pound. By age 18-20, it weighs about three pounds. This is the result of the development and fine-tuning of billions upon billions of neurons consolidated into ‘pathways’ according to their functions.

We have 100 billion neurons in our heads (30,000 neurons can fit on the head of a pin)

Each neuron may be linked with another 5,000-10,000 neurons. The brain has the potential for a quadrillion neural connection.

As neurons connect with other neurons and form ‘pathways’ they lay the biological foundation for what we call ‘learning’.

The Concept of PRUNING

These neuronal pathways/bundles determine or shape our individual temperaments, talents, foibles and quirks as well as the quality of our thinking processes.

The more synaptic firing that occurs across a specific connection, the stronger/denser the pathway becomes.

The brain is very efficient. When the brain is 8 months old, it actually has twice as many neurons as the adult brain. As the brain ages, neurons that are weak or unused or simply don’t fit the job that needs to be done are pruned away.

This pruning leaves more efficient connections for those neurons that are performing the brain’s work. The principle of ‘Use it or lose it’ begins, with non-working ‘couch-potato’ cells dying off while those that are exercised get stronger and develop more connections.

At first, the neuronal activity that determines survival is random and spontaneous, but it becomes more organized as the fetus, and then the baby, receives input from its environment. Neurons that are heavily used form connections with other neurons.

The process of neurons talking to one another is electro-chemical. The action within the neuron is electrical but the message becomes chemical as it travels between neurons. The chemicals traveling between neurons are called neurotransmitters.

When two neurons come together, they don’t actually touch. The dendrites of one neuron take information from the axon of another neuron through chemicals (neurotransmitters) flowing across what we call the SYNAPSE. Electricity fires the synapse and propels chemicals from the axon of one neuron to the dendrites of another, thus connecting the two neurons.