Hyperactive Hippocampal Formation
Dr. Sperling was surprised to see that some people in the study with mild memory problems had an extremely active hippocampal formation when they were trying to process a new memory. This suggested to her that, in these people, the hippocampal formation might have been trying to compensate for the damage done by the advancing Alzheimer's disease process. In people with mild cognitive impairment, thought to be a precursor stage of AD, the hippocampal formation may be going into overdrive. "It works harder to form a new memory. It's revving and driving as fast as it can." During that phase of hyperactivity, people are able to maintain memory. Unfortunately, hyperactivity doesn't continue, and Dr. Sperling hypothesizes that it may be a sign of impending failure of the hippocampal formation. "More and more, we've seen that hyperactivation is a strong predictor of who is going to decline over the next two years. Before the hippocampal formation fails, it seems to make a last-ditch effort to activate as much as it can, struggling to form memories."
Dr. Sperling has followed fifty people over time, including healthy people and those with MCI. The same face-name task was conducted during an fMRI session at two-year intervals. The healthy people showed no difference in the activity of their hippocampal formation. In some of those with MCI, this activity didn't decline much over the two years. But those individuals whose initial scans displayed hyperactivation of the hippocampal formation showed deterioration. "About half of the people in this third group had developed clinical Alzheimer's disease over these two years."
Dr. Sperling's team is now scanning older people every six months with fMRI to track brain function and using PET scans with PiB imaging to detect beta-amyloid plaque formation, as well as to see if there is a correlation between plaque formation and fMRI hyperactivation. Such a connection might have important implications for both diagnosis and drug development. If Dr. Sperling and other researchers are able to establish a definitive link between hippocampal hyperactivation and the impending onset of clinical Alzheimer's disease, fMRI scans of the hippocampal formation could be used as a predictive biomarker to aid physicians in diagnosing the disease and in selecting subjects for clinical trials who are well matched for the potential outcome of the trial. Ultimately, this type of information could be used to start treatment at an earlier stage of AD—a refinement that is much needed.
Previous: Watching the Brain Create Memories
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
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- 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.