Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

1 region, 2 functions: Brain cells' multitasking key to understanding overall brain function

07.03.2013
A region of the brain known to play a key role in visual and spatial processing has a parallel function: sorting visual information into categories, according to a new study by researchers at the University of Chicago.

Primates are known to have a remarkable ability to place visual stimuli into familiar and meaningful categories, such as fruit or vegetables. They can also direct their spatial attention to different locations in a scene and make spatially-targeted movements, such as reaching.

The study, published in the March issue of Neuron, shows that these very different types of information can be simultaneously encoded within the posterior parietal cortex. The research brings scientists a step closer to understanding how the brain interprets visual stimuli and solves complex tasks.

"We found that multiple functions can be mapped onto a particular region of the brain and even onto individual brain cells in that region," said study author David Freedman, PhD, assistant professor of neurobiology at the University of Chicago. "These functions overlap. This particular brain area, even its individual neurons, can independently encode both spatial and cognitive signals."

Freedman studies the effects of learning on the brain and how information is stored in short-term memory, with a focus on the areas that process visual stimuli. To examine this phenomenon, he has taught monkeys to play a simple video game in which they learn to assign moving visual patterns into categories.

"The task is a bit like a baseball umpire calling balls and strikes," he said, "since the monkeys have to sort the various motion patterns into two groups, or categories."

The monkeys master the tasks over a few weeks of training. Once they do, the researchers record electrical signals from parietal lobe neurons while the subjects perform the categorization task. By measuring electrical activity patterns of these neurons, the researchers can decode the information conveyed by the neurons' activity.

"The activity patterns in these parietal neurons carry strong information about the category that each motion pattern gets assigned to during the task," Freedman said.

Over the years, his team's work on categorization has zeroed in on the lateral intraparietal (LIP) area. Studies have shown that this area is vital to directing spatial attention and eye movements. But it had been unclear how an area involved in spatial attention and eye movements could also play a role in non-spatial functions such as visual categorization.

To compare spatial and category functions in the parietal lobe, Freedman and his team added a twist to the monkeys' task. During the category task, the researchers required the subjects to make eye-movements to visual cues at various positions on the computer screen, but the subjects still had to categorize the visual patterns at the same time that they made these eye movements.

Since this parietal brain area is known to be involved in eye movements, the eye movements could have disrupted category information in that part of the brain. Instead, parietal brain cells showed a simultaneous and independent encoding of both eye-movement and category information—multiplexing of information at the level of single brain cells.

"These signals rode right on top of the eye-movement signals," said the study's first author, Chris Rishel, PhD, a recent graduate from Freedman's laboratory. "We could decode both the eye-movement and the category signals with high accuracy. This tells us that different kinds of information that are usually considered quite unrelated were simultaneously and independently represented by neurons in this particular brain area."

Their results, the study authors note, "support the possibility that LIP plays a key role in transforming visual signals in earlier sensory areas into abstract category signals during category-based decision-making tasks."

What does the brain gain from this territorial arrangement?

"There has long been a tendency to look at the many distinct anatomical areas of the cerebral cortex of the brain and to assume that each area is like a specialized module that plays a very specific function." Freedman said. "Our results support the growing sense that most, if not all, of these brain areas have multiple overlapping roles."

A brain that includes such overlapping functional centers may be more efficient, Freedman suggests. "It makes mapping these regions more complicated for scientists like us, but it may boost the brain's capacity. If each area can do a number of different things, you can squeeze a lot more function into the same space."

A next step is to understand how neuronal category representations develop in LIP neurons during the learning process, the authors said.

The paper, "Independent category and spatial encoding in parietal cortex," will be published online March 6 by the journal Neuron. The National Institutes of Health funded this study with additional support from the National Science Foundation, the McKnight Endowment Fund for Neuroscience, the Alfred P. Sloan Foundation and the Brain Research Foundation. Gang Huang, formerly a research technician in the lab, also contributed to the research.

John Easton | EurekAlert!
Further information:
http://www.uchospitals.edu

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>