Memory accuracy and strength can be manipulated during sleep

April 8, 2014
Credit: xiaphias/Wikipedia

The sense of smell might seem intuitive, almost something you take for granted. But researchers from NYU Langone Medical Center have found that memory of specific odors depends on the ability of the brain to learn, process and recall accurately and effectively during slow-wave sleep—a deep sleep characterized by slow brain waves.

The sense of smell is one of the first things to fail in neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, and schizophrenia. Indeed, down the road, if more can be learned from better understanding of how the brain processes odors, researchers believe it could lead to novel therapies that target specific neurons in the brain, perhaps enhancing and .

Reporting in the Journal of Neuroscience online April 9, researchers in the lab of Donald A. Wilson, PhD, a professor in the departments of Child and Adolescent Psychiatry and Neuroscience and Physiology at NYU Langone, and a research scientist at the NYU-affiliated Nathan Kline Institute for Psychiatric Research, showed in experiments with that memory was strengthened when odors sensed the previous day were replayed during sleep. Memories deepened more when odor reinforcement occurred during sleep than when rats were awake.

When the memory of a specific odor learned when the rats were awake was replayed during slow-wave sleep, they achieved a stronger memory for that odor the next day, compared to rats that received no replay, or only received replay when they were awake.

However, when the research team exposed the rats to replay during sleep of an odor pattern that they had not previously learned, the rats had false memories to many different odors. When the research team pharmacologically prevented neurons from communicating to each other during slow-wave sleep, the accuracy of memory of the odor was also impaired.

The rats were initially trained to recognize odors through conditioning. Using electrodes in the olfactory bulb, a part of the brain responsible for perceiving smells, the researchers stimulated different smell perceptions, according to precise patterns of electrical stimulation. Then, by replaying the patterns electrically, they were able to test the effects of slow-wave sleep manipulation.

Replay of learned electrical odors during slow-wave sleep enhanced the memory for those odors. When the learned smells were replayed while the rats were awake, the strength of the memory decreased. Finally, when a false pattern that the rat never learned was incorporated, the rats could not discriminate the smell accurately from the learned odor.

"Our findings confirm the importance of brain activity during sleep for both memory strength and accuracy," says Dr. Wilson, the study's senior author. "What we think is happening is that during slow-wave sleep, neurons in the communicate with each other, and in doing so, strengthen their connections, permitting storage of specific information."

Dr. Wilson says these findings are the first to demonstrate that memory accuracy, not just memory strength, is altered during short-wave . In future research, Dr. Wilson and his team hope to examine how affect and perception.

Explore further: With training, a failing sense of smell can be reversed

Related Stories

With training, a failing sense of smell can be reversed

November 20, 2011

In a new study scientists at NYU Langone Medical Center have shown that the sense of smell can be improved. The new findings, published online November 20, 2011, in Nature Neuroscience, suggest possible ways to reverse the ...

Sound stimulation during sleep can enhance memory

April 11, 2013

Slow oscillations in brain activity, which occur during so-called slow-wave sleep, are critical for retaining memories. Researchers reporting online April 11 in the Cell Press journal Neuron have found that playing sounds ...

Feeling sleepy? Maybe your brain's too full

February 6, 2014

Sleep is an essential state of the brain but why do animals risk the vulnerability that comes with not being conscious for hours? What happens in the brain during sleep that's so vital for life?

Recommended for you

New type of prion may cause, transmit neurodegeneration

August 31, 2015

Multiple System Atrophy (MSA), a neurodegenerative disorder with similarities to Parkinson's disease, is caused by a newly discovered type of prion, akin to the misfolded proteins involved in incurable progressive brain diseases ...

Deciphering the olfactory receptor code

August 31, 2015

In animals, numerous behaviors are governed by the olfactory perception of their surrounding world. Whether originating in the nose of a mammal or the antennas of an insect, perception results from the combined activation ...

How neurons get their branching shapes

August 31, 2015

For more than a hundred years, people have known that dendritic arbors—the projections that neurons use to receive information from other neurons—differ in size and shape depending on neuron type. Now, researchers at ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

russell_russell
not rated yet Apr 08, 2014
Yes. Simply use DNA neuronal repair as your working hypothesis.
Of course you will be the first to let me know if there is even the slightest error in asserting the hypothesis suggested.
thingumbobesquire
1 / 5 (1) Apr 11, 2014
Methinks I smell a rat...No, it's just a behaviorist.
http://thingumbob...dly.html

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.