Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Decoding Short-Term Memory with FMRI

24.02.2009
People voluntarily pick what information they store in short-term memory. Now, using functional magnetic resonance imaging (fMRI), researchers can see just what information people are holding in memory based only on patterns of activity in the brain.

Psychologists from the University of Oregon and the University of California, San Diego, reported their findings in the February issue of Psychological Science. By analyzing blood-flow activity, they were able to identify the specific color or orientation of an object that was intentionally stored by the observer.

The experiments, in which subjects viewed a stimulus for one second and held a specific aspect of the object in mind after the stimulus disappeared, were conducted in the UO's Robert and Beverly Lewis Center for Neuroimaging. In 10-second delays after each exposure, researchers recorded brain activity during memory selection and storage processing in the visual cortex, a brain region that they hypothesized would support the maintenance of visual details in short-term memory.

"Another interesting thing was that if subjects were remembering orientation, then that pattern of activity during the delay period had no information about color, even though they were staring at a colored-oriented stimulus," said Edward Awh, a UO professor of psychology. "Likewise, if they chose to remember color we were able to decode which color they remembered, but orientation information was completely missing."

Researchers used machine-learning algorithms to examine spatial patterns of activation in the early visual cortex that are associated with remembering different stimuli, said John T. Serences, professor of psychology at UC-San Diego. "This algorithm," he said, "can then be used to predict exactly what someone is remembering based on these activation patterns."

Increases in blood flow, as seen with fMRI, are measured in voxels -- small units displayed in a 3-D grid. Different vectors of the grid, corresponding to neurons, respond as subjects view and store their chosen memories. Based on patterns of activity in an individual's visual cortex, located at the rear of the brain, researchers can pinpoint what is being stored and where, Awh said.

The study is similar to one published this month in Nature and led by Vanderbilt University neuroscientist Frank Tong and colleagues, who were able to predict with 80-percent-plus accuracy which patterns individuals held in memory 11 seconds after seeing a stimulus.

"Their paper makes a very similar point to ours," Awh said, "though they did not vary which 'dimension' of the stimulus people chose to remember, and they did not compare the pattern of activity during sensory processing and during memory. They showed that they could look at brain activity to classify which orientation was being stored in memory."

What Awh and colleagues found was that the sensory area of the brain had a pattern of activity that represented only an individual's intentionally stored aspect of the stimulus. This voluntary control in memory selection, Awh said, falls in line with previous research, including that done by Awh and co-author Edward K. Vogel, also of the UO, that there is limited capacity for what can be stored at one time. People choose what is important and relevant to them, Awh said.

"Basically, our study shows that information about the precise feature a person is remembering is represented in the visual cortex," Serences said, "This is important because it demonstrates that people recruit the same neural machinery during memory as they do when they see a stimulus."

That demonstration, Awh said, supports the sensory recruitment hypothesis, which suggests the same parts of the brain are involved in perception of a stimulus and memory storage.

A fourth co-author with Awh, Serences and Vogel was Edward F. Ester, a UO doctoral student. Serences was with the University of California, Irvine, when the project began. The research was primarily funded by a grant from the National Institutes of Health to Awh, and by support from the UO's Robert and Beverly Lewis Center for Neuroimaging.

About the University of Oregon
The University of Oregon is a world-class teaching and research institution and Oregon's flagship public university. The UO is a member of the Association of American Universities (AAU), an organization made up of the 62 leading public and private research institutions in the United States and Canada. The UO is one of only two AAU members in the Pacific Northwest.

Sources: Edward Awh, professor of psychology, 541-346-4983, awh@uoregon.edu; John Serences, assistant professor of psychology, 858-534-3686, jserences@ucsd.edu

Links: Awh faculty page: http://psychweb.uoregon.edu/~pk_lab/awh.htm; Serences faculty page: http://psy.ucsd.edu/people/faculty/bio.php?bio=professors&id=SERENCES; Lewis Center for Neuroimaging: http://lcni.uoregon.edu/

Jim Barlow | Newswise Science News
Further information:
http://www.uoregon.edu

More articles from Health and Medicine:

nachricht Study tracks inner workings of the brain with new biosensor
16.08.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Foods of the future
15.08.2018 | Georg-August-Universität Göttingen

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Metamolds: Molding a mold

20.08.2018 | Information Technology

It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

20.08.2018 | Power and Electrical Engineering

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>