Alzheimer's Disease is essentially caused by massive degeneration in specific areas of the brain, mainly those that serve learning, memory, and other higher levels of cognitive function (eg: the hippocampus and cerebral cortex). Throughout the progression of Alzheimer's Disease neurons rapidly deteriorate and brain tissue begins to show signs of accumulating senile plaques and tangles.

The figures below show how a healthy brain appears, and how one appears in the later stages of degeneration. Note the extensive spaces in the infoldings (fissures and sulci) of the brain. This reflects the loss of brain tissue caused by dementia.

Normally Aged Brain Brain with AD

In the course of aging, the brain is affected by a variety of insults often leading to dementia. One of the major goals of research in the future is the development of rational strategies for promoting successful aging and preventing decline due to dementia. At a cellular level several changes occur in the course of AD

Thus, in order to stop the loss of function and slow the progression of dementia, it is important to discover how to prevent degeneration and the accumulation of plaques and tangles. It is also necessary to stimulate healthy neurons to regenerate their lost processes (a thin branch like structure that comes out of the cell body in order to communicate with other neurons) and restore their synaptic connections. The two neurons shown below illustrate the differences between a healthy neuron (left panel) and one in an AD brain that has lost many of its processes and connections (right panel).

Healthy Neuron AD Neuron


As AD runs its course, senile plaques accumulate and tangles form...

BRAIN FACTS