The human brain is a complex organ that is responsible for our conscious experience. It is composed of billions of neurons which are necessary for communicating and sending signals to and from the body. Early neuroscience believed that we were born with all of our neurons without a possibility of neurogenesis. Knowledge in this area is changing rapidly and what we now understand is neurogenesis does not stop at birth.

 

During the first few years of life there is rapid brain growth. During this time, each neuron in the cerebral cortex has an estimated 2,500 synapses or small gaps between neurons where nerve impulses are relayed. This number quickly becomes 15,000 by age three. What has been revolutionary is the concept of synaptic pruning. The average adult only has half the synapses we had as toddlers! This is because our experiences drive and strengthen certain synapses and others that are not used die or get pruned. The neurons that are used over and over again gain strength. Therefore the brain is able to adapt!

 

The branches of neuroscience are diverse and evolving. They even include everything from mathematical computational fields to behavioral fields. Overall, neuroscience studies the physiologic and biologic substrates that explain how the brain functions and then how this impacts behavior. 

 

The cells and neurons that connect the brain and body are divided into the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). Each is responsible for different parts of gathering information from the environment around us and reacting appropriately.  The CNS is made up of the brain and spinal cord and they are responsible for coordinating information for the entire body. The PNS is responsible for voluntary control of skeletal muscles and involuntary regulation of digestion, respiration, urination and heart rate. 

 

The cerebral cortex is divided into four lobes: frontal, parietal, temporal and occipital. It was once thought that each of these lobes was responsible for very defined functions like vision or hearing. Though this is partially true, we now understand it is more complex than that where areas can overlap and accommodations happen when injury occurs. Combined, the cortex is responsible for making us who we are including our reasoning, memory, emotions and intelligence. 

 

Early researchers believed it was not possible to create new neurons after birth. We now know that the brain’s neuroplasticity allows new pathways to form between both old neurons and new neurons. When a person has a stroke, functional plasticity allows various parts of the brain to take over for the injured parts of the brain. Through structural plasticity, the actual physical structure of the brain can be modified. Exercise increases plasticity through the release of brain-derived neurotrophic factor which allows for actual nerve growth. 

 

What is clear is that knowledge in the area of neuroscience is increasing rapidly. This can alter the way we approach everything from stroke victims, to varied forms or learning and mental health problems. What is comforting is we can impact and improve brain health by our behavior.