Dementia has probably existed for centuries, but it was rare when Alois Alzheimer first reported it in 1907. At this time the average life expectancy was only 50 years of age and only a few people lived to their 6 th or 7 th decade. Scientists estimate that up to 4 million Americans currently suffer from Alzheimer s Disease. The human brain is made up of billions of nerve cells called neurons that communicate with each other via a large array of biological and chemical signals. Each neuron has several parts and each part has a specific function.
Glial cells support and nourish the neurons.
Neurons communicate with each other through small gaps called synapses using a combination of electrical discharge and a secreted substance called a neurochemical. Scientists estimate that each one of our neurons can have up to 15,000 synapses. There are several neurochemicals and each one can either turn on or turn off a signal. Millions of signals travel back and forth across the synapses in a fraction of a second at any given time. The brain is divided into the right and left hemisphere and each hemisphere is divided into 4 lobes called the frontal, temporal, occipital and parietal lobes.