Scientists discover new mechanism that may be important for learning and memory

(Medical Xpress) -- New findings in mice suggest that the timing when the neurotransmitter acetylcholine is released in the brain’s hippocampus may play a key role in regulating the strength of nerve cell connections, called synapses. Understanding the complex nature of neuronal signaling at synapses could lead to better understanding of learning and memory, and novel treatments for relevant disorders, such as Alzheimer’s disease and schizophrenia.

Neurons in the hippocampus, one of the parts of the brain that is thought to have a critical function in learning and , communicate with each other at synapses by releasing various neurotransmitters, including acetylcholine and glutamate, which stimulate electrical signals in the adjacent neurons.

For years, neuroscientists have been working to determine which cellular processes allow humans to learn from experience and store memories, and how these processes are compromised by conditions such as schizophrenia and Alzheimer’s disease. Now, researchers from the National Institute of Environmental Health Sciences (NIEHS), which is part of the National Institutes of Health, believe they have found one such mechanism for synchronizing changes in the strength of synapses. The results of the study will be published online July 13 in the journal Neuron.

“We’ve demonstrated that when we stimulate the release of acetylcholine at just the right time in the hippocampus, we can induce a cellular change at synapses that use glutamate,” said Jerrel Yakel, Ph.D., a senior investigator in the NIEHS Laboratory of Neurobiology and co-author of the paper.

Previous work by other researchers had established that learning and memory is mediated by the strengthening or weakening of , where electrical signals that last less than a hundredth of a second release neurotransmitters that change the electrical impulses of the connected neurons. In this study, Yakel and Zhenglin Gu, Ph.D., a research fellow in Yakel’s group and co-author of the publication, used molecular biology techniques to get some of the neurons in mouse cells to produce a special light-sensitive protein, and then used a laser to stimulate these neurons to release acetylcholine.

“A change of even a few hundredths of a second in the timing of acetylcholine release can make a difference,” said Gu. “No one had shown this was important until now.”

Yakel said the findings are also a potentially important step in the study of disorders that affect learning and memory, such as Alzheimer’s disease and schizophrenia, where the acetylcholine system and hippocampus are known to play critical roles. For example, amyloid beta peptide is the major component of plaques that form in the brains of Alzheimer’s patients and is thought to participate in the memory loss associated with Alzheimer’s disease. In this report, Yakel and Gu expand upon earlier findings that amyloid beta peptide disrupts acetylcholine’s ability to regulate synaptic strength.

Provided by National Institutes of Health

5 /5 (1 vote)

Related Stories

Mechanism of nicotine's learning effects explored

Apr 04, 2007

While nicotine is highly addictive, researchers have also shown the drug to enhance learning and memory—a property that has launched efforts to develop nicotine-like drugs to treat cognitive deficits in Alzheimer’s and ...

Astrocytes affect brain's information signaling

Jun 14, 2010

Astrocytes are the most common type of cell in the brain and play an important role in the function of neurons - nerve cells. New research from the University of Gothenburg, Sweden, shows that they are also directly involved ...

Recommended for you

Common infections tied to some stroke risk in kids

2 hours ago

A new study suggests that colds and other minor infections may temporarily increase stroke risk in children. The study found that the risk of stroke was increased only within a three-day period between a ...

Celebrities in 'Ice Bucket Challenge' to fight disease

13 hours ago

Steven Spielberg, Justin Bieber and Bill Gates are among many celebrities pouring buckets of ice water over their heads and donating to fight Lou Gehrig's disease, in a fundraising effort that has gone viral.

Study helps explain why elderly have trouble sleeping

14 hours ago

As people grow older, they often have difficulty falling asleep and staying asleep, and tend to awaken too early in the morning. In individuals with Alzheimer's disease, this common and troubling symptom ...

Targeted brain training may help you multitask better

16 hours ago

The area of the brain involved in multitasking and ways to train it have been identified by a research team at the IUGM Institut universitaire de gériatrie de Montréal and the University of Montreal.

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

hush1
not rated yet Jul 14, 2011
A change of even a few hundredths of a second in the timing of acetylcholine release can make a difference, said Gu. No one had shown this was important until now. - Zhenglin Gu

"...induce a cellular change at synapses that use glutamate,..." - Jerrel Yakel

Is there any way to ascertain to when the amount of difference (in timing) has a cognitive (macrolevel conscious) effect?

Is there self correction? Stronger synapses require less time, weaker synapses require more time? Suggesting feedback to control the potential.

Great work.