MAY 09, 2016 7:27 PM PDT

How Alzheimer's Disrupts Memory

Alzheimer’s disease is the sixth leading cause of death in the United States. Currently 1 in 3 senior citizens (over the age of 65) will die dealing with the disease and its effects on memory and cognition, if not from the disease directly. It’s estimated that 5 million Americans have it presently and rates are increasing each year. With such large numbers of people affected, both patients and their caregivers and families, naturally research into the causes and possible treatments are at the forefront of neuroscience studies. Scientists at the Gladstone Institutes have recently discovered how the major genetic risk factor for Alzheimer’s disease causes memory impairment.
 
A protein associated with Alzheimer's disrupts memory

Memory in the human brain is much like the playback of a movie or television show. The brain recalls the memory as if watching it again, and a person remembers a skill or event. When this process is disrupted, as it is in Alzhiemer’s disease, not only is it difficult to recall things, but the brain also has trouble forming new memories.
 
A specific gene related to this function, the apoE4 gene, creates a protein of the same name that markedly increases a person’s risk for Alzheimer’s disease and occurs in 65%–80% of people with Alzheimer’s disease. There are three different types of the APOE gene, called alleles. The apoE4 allele, present in about 20% of the population, increases the risk for Alzheimer’s. apoE4 alleles are the greatest genetic risk factor for late-onset Alzheimer’s. However, this doesn’t mean that those with the apoE4 protein will absolutely get Alzheimer’s disease. Many people develop Alzheimer’s who don’t have an apoE4 allele. It does, however, increase your risk for developing the disease as well as lower the age of potential disease onset.
 
The new research at Gladstone has found more information on how the apoE4 protein works in patients with Alzheimer’s. The protein changes the activity of neurons in the hippocampus, which is an important memory center in the brain that is severely affected by Alzheimer’s disease. In this region, apoE4 decreases two types of brain activity that are important for memory formation: sharp wave ripples and coincident slow gamma activity. During the ripples, prior experiences are replayed numerous times to help preserve the memory of them, and the slow gamma activity that occurs during the ripples helps to ensure that the replay of those memories is accurate.
 
First author Anna Gillespie, PhD, a former graduate student in the Huang lab at Gladstone said in a press release, “When we experience something new, cells in the hippocampus fire in a particular order. Later, these same cells fire over and over again in the same order to replay the event, which helps consolidate the memory so we don’t forget it. Slow gamma activity that occurs during the ripples organizes the firing of these cells. If this activity is disrupted, the playback will be disorganized, compromising the memory.”
 
Researchers used lab mice and looked at the differences in those with apoE4 and those with normal apoE3. Mice with apoE4 had fewer ripples than mice with the normal apoE3 protein, and they had less slow gamma activity during the ripples and it was these differences that pointed to the coordination of cell firing during memory playback as a key player in developing Alzheimer’s disease. The team hopes that understanding the mechanism of these proteins will lead to better treatments for the disease. Take a look at the video below to hear more about the research.
 Sources: Gladstone Institute, Alzheimer's Association
About the Author
  • I'm a writer living in the Boston area. My interests include cancer research, cardiology and neuroscience. I want to be part of using the Internet and social media to educate professionals and patients in a collaborative environment.
You May Also Like
MAY 15, 2021
Drug Discovery & Development
New Weight Loss Drug Converts Energy-Storing Fat into Energy-Burning Fat
MAY 15, 2021
New Weight Loss Drug Converts Energy-Storing Fat into Energy-Burning Fat
According to the World Health Organization (WHO), in 2016, around 2 billion adults around the world were overweight ...
MAY 15, 2021
Neuroscience
Eye Scans May Indicate Early Signs of Alzheimer's
MAY 15, 2021
Eye Scans May Indicate Early Signs of Alzheimer's
Researchers from the University of California San Francisco have found that retinal scans can detect changes in blood ve ...
JUN 03, 2021
Cannabis Sciences
Cannabis Use in First Weeks of Pregnancy May Affect Brain Activity
JUN 03, 2021
Cannabis Use in First Weeks of Pregnancy May Affect Brain Activity
Researchers from the University of Alberta in Canada have found that zebrafish exposed to certain cannabinoids early in ...
JUN 05, 2021
Technology
Robotic Exoskeleton May Improve Response to Exercise-based Rehabilitation in People With Severe MS
JUN 05, 2021
Robotic Exoskeleton May Improve Response to Exercise-based Rehabilitation in People With Severe MS
Robots are most often found in science fiction. Recently, however, researchers are using robot-like technology to help p ...
JUL 20, 2021
Neuroscience
How much sleep do you need? It's all in the genes.
JUL 20, 2021
How much sleep do you need? It's all in the genes.
Genetics holds crucial information about how much sleep we need
JUL 23, 2021
Neuroscience
Does the Rise of Neurotech Spell the End of Humanity as We Know it?
JUL 23, 2021
Does the Rise of Neurotech Spell the End of Humanity as We Know it?
Researchers from Imperial College London have written an overview of currently available commercial brain-computer inter ...
Loading Comments...