'Waves' of neural activity give new clues about Alzheimer's

September 6, 2017 by Laura Chaparro, Spanish Foundation for Science and Technology (FECYT)
Every one to four seconds waves of neural activity travel from one point to another in the cerebral cortex. Credit: Penn State

While unconscious during deep sleep, slow-wave neuron activity travels across the cerebral cortex. This phenomenon is related to the consolidation of memory. A European project called SloW Dyn, led by Spanish scientists, has now revealed anomalies in this activity in mice displaying a decline similar to Alzheimer's.

During , large populations of neurons in the and subcortical brain structures simultaneously discharge electrical pulses. These are slow oscillations that travel as 'waves' of neural activity from one point to another in the cortex once every one to four seconds.

"This global rhythmic activity, controlled by the cerebral cortex, is associated with a lack of consciousness," says Mavi Sanchez-Vives, whose research team has suggested that it is the default activity of the cortical circuits. These oscillations consolidate memory and synaptic plasticity and maintain metabolic and cellular function, among other things. The researchers have now discovered differences in this between healthy mice and mice with cognitive decline similar to Alzheimer's due to premature aging.

"We detected a decrease in the frequency of the oscillations which were also more irregular and had a lower high-frequency content of 15 to 100 hertz," says Sanchez-Vives, also from the Catalan Institution for Research and Advanced Studies (ICREA).

The study, published in the journal Frontiers in Aging Neuroscience, highlights how some of these changes have also been observed in patients with Alzheimer's disease for which reason, according to the authors, the animal model could help in studying the disease.

Cause or effect of diseases

The relationship between slow oscillations and neurodegenerative diseases is twofold. When there are pathologies that disturb cortical circuits, they are often reflected in the disruption of slow waves. "We are studying what those changes tell us about the altered underlying mechanisms," says the researcher.

Furthermore, the wave alterations will likely be associated with sleep problems, which may influence the development of a disease. "For example, if periods are disrupted, cognitive functions such as attention and memory can be negatively affected," Sanchez-Vives notes.

In order to measure these oscillations, scientists use EEGs, which record a person's brain activity while sleeping. Throughout the SloW Dyn project, experts will measure the waves of thousands of people and will ascertain how they change with age. The tools which they have developed for this purpose are an instrument that registers brain activity and an app.

"This will provide massive information about the composition of sleep, the synchronization of activity and the anomalies that can occur as a result of aging or specific pathologies," says the scientist. Researchers hope that these records will also give them clues about the therapeutic potential of restoring slow waves when they are impaired. "We are trying to understand a phenomenon which, although seemingly very simple, has the power to disconnect consciousness," says Sanchez-Vives.

Explore further: How the brain consolidates memory during deep sleep

More information: María V. Sánchez-Vives, Marcello Massimini y Maurizio Mattia. "Shaping the Default Activity Pattern of the Cortical Network" Neuron 94 (5) june 2017. DOI: 10.1016/j.neuron.2017.05.015

Patricia Castaño-Prat, María Pérez-Zabalza, Lorena Pérez-Méndez, Rosa M. Escorihuela y María V. Sánchez-Vives. "Slow and Fast Neocortical Oscillations in the Senescence-Accelerated Mouse Model SAMP8" Frontiers in Aging Neuroscience 9:141 may 2017. DOI: 10.3389/fnagi.2017.00141

Related Stories

How the brain consolidates memory during deep sleep

April 14, 2016
Research strongly suggests that sleep, which constitutes about a third of our lives, is crucial for learning and forming long-term memories. But exactly how such memory is formed is not well understood and remains, despite ...

Rhythm of oscillations in cerebral cortex, key to understanding Down syndrome

April 5, 2016
Cerebral activity is governed by a fine balance between neuronal excitation and inhibition. Specifically, neurons are activated by excitation mechanisms tightly regulated by inhibition processes. For certain functions, the ...

Pink noise synced to brain waves deepens sleep and boosts memory in older adults

April 25, 2017
Gentle sound stimulation—such as the rush of a waterfall—synchronized to the rhythm of brain waves significantly enhanced deep sleep in older adults and improved their ability to recall words, reports a new Northwestern ...

Sound waves boost older adult' memory, deep sleep

March 8, 2017
Gentle sound stimulation—such as the rush of a waterfall—synchronized to the rhythm of brain waves significantly enhanced deep sleep in older adults and improved their ability to recall words, reports a new Northwestern ...

Controlling memory by triggering specific brain waves during sleep

July 6, 2017
Have you ever tried to recall something just before going to sleep and then wake up with the memory fresh in your mind? While we absorb so much information during the day consciously or unconsciously, it is during shut eye ...

Slow waves may explain the brain's disconnect during dreaming

January 27, 2016
When we're dreaming, our brains appear almost as active as when we are awake, yet we remain asleep and oblivious to our surroundings.

Recommended for you

Attention, please! Anticipation of touch takes focus, executive skills

December 12, 2018
Anticipation is often viewed as an emotional experience, an eager wait for something to happen.

Study highlights potential benefits of continuous EEG monitoring for infant patients

December 12, 2018
A recent retrospective study evaluating continuous electroencephalography (cEEG) of children in intensive care units (ICUs) found a higher than anticipated number of seizures. The work also identified several conditions closely ...

The importins of anxiety

December 11, 2018
According to some estimates, up to one in three people around the world may experience severe anxiety in their lifetime. In a study described today in Cell Reports, researchers at the Weizmann Institute of Science have revealed ...

How returning to a prior context briefly heightens memory recall

December 11, 2018
Whether it's the pleasant experience of returning to one's childhood home over the holidays or the unease of revisiting a site that proved unpleasant, we often find that when we return to a context where an episode first ...

Neurons in the brain work as a team to guide movement of arms, hands

December 11, 2018
The apparent simplicity of picking up a cup of coffee or turning a doorknob belies the complex sequence of calculations and processes that the brain must undergo to identify the location of an item in space, move the arm ...

Using neurofeedback to prevent PTSD in soldiers

December 11, 2018
A team of researchers from Israel, the U.S. and the U.K. has found that using neurofeedback could prevent soldiers from experiencing PTSD after engaging in emotionally difficult situations. In their paper published in the ...

0 comments

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.