Scientists have said that the human brain is the most complicated organ in the body—in fact, many claim that it is the single most complex natural or man-made entity on our planet. The mighty brain we carry in our heads processes billions of messages a minute, day and night, week after week, year after year, decade after decade. Its knowledge base expands and grows more complex with every new bit of information acquired, making informed decisions and taking creative leaps based on this new input, all the while retaining the older bits.
Tens of billions of nerve cells, called neurons, most smaller than a grain of sand, are compressed into an incredibly small space about the size of a cantaloupe. Each has a defined function, carrying out billions of distinct communications as we go through our day. At the same time, outside our awareness, the brain regulates breathing, heartbeat, digestion, sensory organs, excretion, and other functions. The brain is so important that even though it accounts for only 2 percent of our body weight, it receives 20 percent of our blood supply.
Drawing showing damage caused by AD
Doctors track progress by patients clock drawings
Two beta-amyloid plaques surrounded by neurons
The beta-amyloid cascade begins with cutting of APP
Dr. Ron Petersen
A method of diagnosing AD is cognitive testing
Exercises during cognitive testing
Yet we give little thought to our brain until we encounter a problem in our ability to think. If Alzheimer's disease (AD) develops, the brain slowly loses its ability to make and retrieve memories and process information. A friend's name that was once familiar now eludes us. Last week's Thanksgiving dinner draws a blank. A naval engineer who once performed algebra, calculus, and trigonometry can no longer balance his checkbook. A grandmother cannot recall her family's favorite cookie recipe and is not even safe in the kitchen anymore, as she forgets to shut off the oven. Bits and pieces of life are lost—a doctor's appointment, a child's birth date, the name of a flower, even a spouse's face. Eventually, even simple thinking skills are lost.
We don't yet have all the answers about what triggers the cascade of events that eventually leads to AD, or why some changes in memory and thinking skills that occur even in healthy aging become much more destructive in people who have the disease. But we have learned a lot about the major characteristics of the disease and the way in which it develops over time. We also know that the processes in the brain that lead to the physical and behavioral changes in people with AD begin long before anyone is aware that a problem exists—ten to twenty years before significant memory loss occurs.
Next: The First Discovery
Excerpted from THE ALZHEIMER'S PROJECT: MOMENTUM IN SCIENCE, published by Public Affairs, www.publicaffairsbooks.com.
In This Section
Momentum in Science: The Supplementary Series
- Understanding and Attacking Alzheimer's 12 min
- How Far We Have Come in Alzheimer's Research 15 min
- Identifying Mild Cognitive Impairment 20 min
- The Role of Genetics in Alzheimer's 12 min
- Advances in Brain Imaging 11 min
- Looking Into the Future of Alzheimer's 6 min
- The Connection Between Insulin and Alzheimer's 21 min
- Inflammation, the Immune System, and Alzheimer's 29 min
- The Benefit of Diet and Exercise in Alzheimer's 16 min
- Cognitive Reserve: What the Religious Orders Study is Revealing about Alzheimer's 20 min
- Searching for an Alzheimer's Cure: The Story of Flurizan 30 min
- The Pulse of Drug Development 15 min
- The DeMoe Family: Early-Onset Alzheimer's Genetics 25 min
- The Nanney/Felts Family: Late-Onset Alzheimer's Genetics 20 min
- The Quest for Biomarkers 17 min
Video: Inside the Brain: Unraveling the Mystery of Alzheimer's Disease
This 4-minute captioned video shows the progression of Alzheimer's disease in the brain.
Inside the Brain: An Interactive Tour
The Brain Tour explains how the brain works and how Alzheimer's affects it.
Alzheimer's Disease: Unraveling the Mystery
This book explains what AD is, describes the main areas in which researchers are working, and highlights new approaches for helping families and friends care for people with AD.
- About The Scientists
Connect with Alzheimer's Research
Find out how you can participate in clinical trials or studies, find a research center, or get up-to-date information at 1-800-438-4380.
The Alzheimer's Association 24/7 Helpline provides reliable information and support to all those who need assistance. Call us toll-free anytime day or night at 1-800-272-3900.
- Create A Tribute
Honor someone you care about and share your stories by contributing to The Tribute Wall on Facebook.
The Alzheimer's Association message boards and chat rooms are your online communication forum. Share your thoughts and experiences, query your colleagues, and make new friends.
- Rapid advances in our knowledge about AD have led to the development of promising new drugs and treatment strategies. However, before these new strategies can be used in clinical practice, they must be shown to work in people. Advances in prevention and treatment are only possible thanks to volunteers who participate in clinical trials.
- Among those touched by Alzheimer's (excluding self), nearly one-third provide support as a friend or relative, another 3% provide support as a healthcare professional, and the remaining two-thirds provide no support to the person suffering from Alzheimer's. When support is provided, it most often entails emotional support, followed by care-giving support. While small in comparison, more than one person in ten is providing financial support. Read more.