Researchers use rhythmic brain activity to track memories in progress

June 5, 2014
Tuning functions constructed from spatially distributed oscillatory alpha activity are shown during the storage of a single oriented line in visual working memory. Early transient peaks (top) and later sustained peaks (bottom) correspond to distinct stimulus-specific patterns of neural activity observed during stimulus encoding and storage, respectively. Credit: Edward Awh

University of Oregon researchers have tapped the rhythm of memories as they occur in near real time in the human brain.

Using electroencephalogram (EEG) electrodes attached to the scalps of 25 student subjects, a UO team led by psychology doctoral student David E. Anderson captured synchronized neural activity while they held a held a simple oriented bar located within a circle in short-term memory. The team, by monitoring these alpha rhythms, was able to decode the precise angle of the bar the subjects were locking onto and use that to predict which individuals could store memories with the highest quality or precision.

The findings are detailed in the May 28 issue of the Journal of Neuroscience. A color image illustrating how the item in memory was tracked by rhythmic brain activity in the alpha frequency band (8 to 12 beats per second) is on the journal's cover page to showcase the research.

Although past research has decoded thoughts via brain activity, standard approaches are expensive and limited in their ability to track fast-moving , said Edward Awh, a professor in the UO's Department of Psychology and Institute of Neuroscience. The new findings show that EEG measures of synchronized can precisely track the contents of memory at almost the speed of thought, he said.

"These findings provide strong evidence that these electrical oscillations in the alpha frequency band play a key role in a person's ability to store a limited number of items in working memory," Awh said. "By identifying particular rhythms that are important to memory, we're getting closer to understanding the low-level building blocks of this really limited cognitive ability. If this rhythm is what allows people to hold things in mind, then understanding how that rhythm is generated—and what restricts the number of things that can be represented—may provide insights into the basic capacity limits of the mind."

The video will load shortly
Edward Awh briefly describes the finding of his study on tracking early processing of working memory, and the differences between EEG and fMRI is studying the process. Credit: University of Oregon

The findings emerged from a basic research project led by Awh and co-author Edward K. Vogel—funded by the National Institutes of Health—that seeks to understand the limits of storing information. "It turns out that it's quite restricted," Awh said. "People can only think about a couple of things at a time, and they miss things that would seem to be extremely obvious and memorable if that limited set of resources is diverted elsewhere."

Past work, mainly using functional magnetic resonance imaging (fMRI), has established that brain activity can track the content of memory. EEG, however, provides a much less expensive approach and can track mental activity with much a higher temporal resolution of about one-tenth of a second compared to about five seconds with fMRI.

"With EEG we get a fine-grained measure of the precise contents of memory, while benefitting from the superior temporal resolution of electrophysiological measures," Awh said. "This EEG approach is a powerful new tool for tracking and decoding mental representations with high . It should provide us with new insights into how rhythmic brain activity supports core processes."

Explore further: Similarity breeds proximity in memory, researchers find

Related Stories

Similarity breeds proximity in memory, researchers find

March 5, 2014
Researchers at New York University have identified the nature of brain activity that allows us to bridge time in our memories. Their findings, which appear in the latest issue of the journal Neuron, offer new insights into ...

Brain waves reveal video game aptitude

October 24, 2012
Scientists report that they can predict who will improve most on an unfamiliar video game by looking at their brain waves.

What happened when? How the brain stores memories by time

March 12, 2014
(Medical Xpress)—Before I left the house this morning, I let the cat out and started the dishwasher. Or was that yesterday? Very often, our memories must distinguish not just what happened and where, but when an event occurred—and ...

Remembrance of things future: Long-term memory sets the stage for visual perception

December 28, 2011
(Medical Xpress) -- Rather than being a passive state, perception is an active process fueled by predictions and expectations about our environment. In the latter case, memory must be a fundamental component in the way our ...

Recommended for you

In witnessing the brain's 'aha!' moment, scientists shed light on biology of consciousness

July 27, 2017
Columbia scientists have identified the brain's 'aha!' moment—that flash in time when you suddenly become aware of information, such as knowing the answer to a difficult question. Today's findings in humans, combined with ...

Scientists block evolution's molecular nerve pruning in rodents

July 27, 2017
Researchers investigating why some people suffer from motor disabilities report they may have dialed back evolution's clock a few ticks by blocking molecular pruning of sophisticated brain-to-limb nerve connections in maturing ...

Social influences can override aggression in male mice, study shows

July 27, 2017
Stanford University School of Medicine investigators have identified a cluster of nerve cells in the male mouse's brain that, when activated, triggers territorial rage in a variety of situations. Activating the same cluster ...

Scientists become research subjects in after-hours brain-scanning project

July 27, 2017
A quest to analyze the unique features of individual human brains evolved into the so-called Midnight Scan Club, a group of scientists who had big ideas but almost no funding and little time to research the trillions of neural ...

Researchers reveal unusual chemistry of protein with role in neurodegenerative disorders

July 27, 2017
A common feature of neurodegenerative diseases is the formation of permanent tangles of insoluble proteins in cells. The beta-amyloid plaques found in people with Alzheimer's disease and the inclusion bodies in motor neurons ...

Mother's brain reward response to offspring reduced by substance addiction

July 27, 2017
Maternal addiction and its effects on children is a major public health problem, often leading to high rates of child abuse, neglect and foster care placement. In a study published today in the journal Human Brain Mapping, ...

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.