The Revolution in Brain Science

Neuroplasticity and Neurogenesis

The BrainThe adult brain has long been considered

stable and unchanging, except for the

inevitable decline that occurs with aging.

This view is being challenged with clear

evidence that structural changes occur in

the brain throughout life, including the

generation of new neurons and other brain cells,

and connections between and among neurons.

Structural Changes

The structural changes seen in the brain

may be required to provide the extra

capacity we need for dealing with

complexity.

Structural Changes (Con’t)

It may also provide the underpinning for the

adaptability and flexibility, or plasticity that is

required for dealing with the variety of

challenges that we face throughout life.

Repair

Structural plasticity provides the mechanism for the brain to repair itself. All organs of the body have some capacity to repair themselves following minor injury. Skin, liver, heart, kidney, lung, and blood have some level of repair capacity, and most have the capacity to generate new cells to replace damaged ones, at least to a small extent.

Early Dogma

Until recently, the brain was considered

unique in its lack of ability to repair itself

once it had matured to adulthood. “In the

adult center the nerve paths are something

fixed and immutable, nothing may be

regenerated” (S. Ramon y Cajal, 1928). In

general in was summed up as “try not to damage

your brain, because there is no way to fix it.”

Neuroplasticity

Neuro refers to the brain

Plasticity refers to the ability to change

itself, to change its structure and

function.

Neuroplasticity occurs in the brain

1 – At the beginning of life: when the immature brain organizes itself.

2 – In case of brain injury: to compensate for lost functions or maximize remaining functions.

3 – Through adulthood: whenever something new is learned and memorized

Neurogenesis

Neurogenesis means the production of new

neurons.

The observation that neurogenesis

continues in the adult brain has led to the

discovery that there are stem cells in the

adult brain that generate the new neurons.

Stem Cells

A stem cell is an uncommitted cell that,

when it divides, can give rise to any or all

the three main cell lineages of the brain:

neurons, astrocytes, and oligodendrocytes.

Where does cell genesis occur?

Neurogenesis, the process of generating new neurons, does not occur in every part of the brain. In fact, it only occurs in two areas:the hippocampus (discovered in 1998) and the olfactory bulb.New neurons in the hippocampus seem to help enhance learning and rebuild lost memories.

Summary

The organization and layout of the nerve

cells in the human brain is truly remarkable.

The brain continues to change and adapt, as

well as repair itself, throughout life. The

brain follows an overall plan of development

but then alters based on experience,

stimulation, and the environment.

Brain Plasticity

Read and make summary notes from the

following website:http://faculty.washington.edu/chudler/plast.html

1. What are the benefits of brain plasticity?

When is it not a benefit?

2. How could neurogenesis revolutionize the

treatment of an unhealthy brain?