The fastest nerve impulses ever recorded can travel at 288 miles per hour.
A nerve impulse is how a neuron communicates with another cell through changes in electrical stimulus known as action potential. A neuron is made of up of axon and dendrites which use chemical and electrical signals to various parts of the body including the brain. A nerve is a defined as a group of fibrous tissue that holds neurons protected by a glossy white sheath known as myelin. It is estimated that 86 billion neurons are found in the human brain.
"Neurons (also called neurons or nerve cells) are the fundamental units of the brain and nervous system, the cells responsible for receiving sensory input from the external world, for sending motor commands to our muscles, and for transforming and relaying the electrical signals at every step in between. More than that, their interactions define who we are as people." - Queensland Brain Institute of Australia.
Neurogenesis is the process of forming of new neurons or chemical and electrical pathways. This happens most readily as children learn and develop new skills, but contrary to previous thought, it can also happen as an adult. As only a recent area of study, researchers are now learning that certain things effect neurogenesis in the adult brain.
At this time, researchers believe the main cause of declining neurons is aging and is not linked to specific disease or diagnosis. The good news is that the way we age is actually more in our control than we are lead to believe. While genetic factors play a small role, the expression of those genes heavily rely on our lifestyle factors. In a similar way we can increase or decrease neurogenesis in our brains.
From the age of 20-90 the brain can actually decreased in size by around 5-10%. There are lifestyle factors that research suggests a decrease in neurogenesis which include high levels of blood glucose from foods, lack of exercise and mobility, and not enough sleep. This article also says a decrease in neurogenesis has also been associated with mental health conditions such as depression, anxiety, and posttraumatic stress disorder.
With a specific focus and conscious effort on your health and wellness, this does not have be your future! There are many ways to increase neurogenesis and neuroplasticity even as an adult. Exercise, learning a new skill, meditation, eating more "brain food", and being creative in music or art are some of the ways our brains can make new pathways and connections.
In contrast, it has been suggested that exercise can increase neurogenesis in the dentate gyrus, resulting in more new neurons being produced. Adult neurogenesis can also be stimulated by social interaction, learning, and a healthy diet.
https://www.youtube.com/watch?v=B_tjKYvEziI Great TED talk about Neurogenesis