Alzheimer's drug boosts perceptual learning in healthy adults

Sep 16, 2010

Research on a drug commonly prescribed to Alzheimer's disease patients is helping neuroscientists at the University of California, Berkeley, better understand perceptual learning in healthy adults.

In a new study, to be published online Thursday, Sept. 16, in the journal , researchers from UC Berkeley's Helen Wills Neuroscience Institute and School of Optometry found that study participants showed significantly greater benefits from practice on a task that involved discriminating directions of motion after they took donepezil, sold under the brand name Aricept, compared with a placebo.

Neither the researchers nor the participants knew whether they were taking the placebo or donepezil, a cholinesterase inhibitor that enhances the effects of the in the brain. Cholinesterase inhibitors act by blocking an enzyme that breaks down acetylcholine. Acetylcholine is known to play an important role in mediating and, in animal studies, has been found to promote changes in the brain that are associated with learning.

Donepezil, like other cholinesterase inhibitors, is used to treat early stages of and dementia. Previous research on donepezil has focused primarily on its beneficial effects on quality of life and clinical symptoms in patient populations. However, little was known about the specific that are enhanced by this drug.

"We wanted to better understand the biological mechanisms that underlie the ability to learn new tasks and to shed light on which specific neural processes are being enhanced by donepezil," said the study's principal investigator, Michael Silver, UC Berkeley assistant professor of optometry and neuroscience. "This is the first study to show that donepezil can enhance learning of a new skill, even in normal, healthy people."

The researchers tested 12 healthy, non-smoking adults ages 18-35. Subjects were tasked with detecting whether or not two fields of moving dots, presented one after the other, were moving in the same direction.

Each subject completed two 5-day courses of training on this task. In one of these courses of training, subjects ingested 5 milligrams of donepezil before every training session, and in the other, they took a placebo capsule before each training session. On average, the amount of improvement in performance of the task due to training increased two-fold when training occurred under the influence of donepezil.

However, the study authors noted that the improvements in the task being learned did not result in the same amount of improvement in performance on new motion direction discrimination tasks.

"The effects of donepezil were very specific to the task that the subjects were learning and practicing, and improvements elsewhere were much more moderate," said study lead author Ariel Rokem, a UC Berkeley post-doctoral fellow at the Helen Wills Neuroscience Institute. "As a comparison, with practice, a fruit inspector may become very good at judging small differences in color among red apples, but this learning may not completely transfer to the ability to discriminate shades of green apples."

It would be helpful to test the effectiveness of donepezil on other forms of learning, the study authors said. "We've established that donepezil enhances learning, so now we want to understand how this happens in the brain," said Silver. "We have a study underway where we use brain imaging to measure how the brain changes with learning and the impact of donepezil on these neural changes."

The researchers said that if enhancing the activity of acetylcholine in the brain is shown to benefit other forms of perceptual learning, it could eventually lead to clinical treatments for people with conditions other than Alzheimer's.

"Perceptual learning tasks are used to help patients with clinical conditions such as dyslexia and amblyopia," said Rokem. "Further research could find that cholinesterase inhibitors boost the effectiveness of treatments for these patients."

Explore further: Clot dissolver tPA's tardy twin could aid in stroke recovery

Related Stories

Multi-sensory training: Faster learning

Aug 15, 2006

U.S. scientists from Boston University and UCLA say the use of multi-sensory training programs helps people improve low-level perceptual task learning.

Drugs may not delay onset of dementia; and more

Nov 27, 2007

Researchers have examined the evidence in favour of giving people considered to be close to developing dementia the drugs that are most commonly used to treat the condition itself. They have concluded that these drugs (cholinesterase ...

Recommended for you

New test to help brain injury victims recover

23 hours ago

A dynamic new assessment for helping victims of trauma to the brain, including those suffering from progressive conditions such as dementia, has been developed by a clinical neuropsychologist at the University ...

See-through sensors open new window into the brain

Oct 21, 2014

(Medical Xpress)—Developing invisible implantable medical sensor arrays, a team of University of Wisconsin-Madison engineers has overcome a major technological hurdle in researchers' efforts to understand ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

bottomlesssoul
not rated yet Sep 16, 2010
I've been using Donepezil analogs for years now. It really seems to work but I would be happier to know it wasn't purely placebo.