Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The brain's 'inner GPS' gets dismantled

11.11.2014

Imagine being able to recognize your car as your own but never being able to remember where you parked it.

Researchers at University of California, San Diego School of Medicine have induced this all-too-common human experience - or a close version of it - permanently in rats and from what is observed perhaps derive clues about why strokes and Alzheimer's disease can destroy a person's sense of direction.


The rat with the MEC lesion (right) shows a poor ability to remember the location of the resting platform (red dot).

Credit: UC San Diego School of Medicine

The findings are published online in the current issue of Cell Reports.

Grid cells and other specialized nerve cells in the brain, known as "place cells," comprise the brain's inner GPS, the discovery of which earned British-American and Norwegian scientists this year's Nobel Prize for medicine.

In research that builds upon the Nobel Prize-winning science, UC San Diego scientists have developed a micro-surgical procedure that makes it possible to remove the area of the rat's brain that contains grid cells and show what happens to this hard-wired navigational system when these grid cells are wiped out.

One effect, not surprisingly, is that the rats become very poor at tasks requiring internal map-making skills, such as remembering the location of a resting platform in a water maze test.

"Their loss of spatial memory formation was not a surprise," said senior co-author Robert Clark, PhD, a professor of psychiatry. "It's what would be expected based on the physiological characteristics of that area of the brain," which is known as the entorhinal cortex and is the first brain region to break down in Alzheimer's disease.

But the rats retained a host of other memory and navigation-related skills that scientists had previously speculated would be destroyed without grid cells.

"The surprise is the discovery of the type of memory formation that was not disrupted by the removal of the grid cell area," Clark said.

Specifically, UC San Diego scientists were able to show that even without grid cells rats could still mark spatial changes in their environment. They could, for example, notice when an object in a familiar environment was moved a few inches and they could recognize objects, such as a coffee mug or flower vase, and remember later that they had seen these objects before.

Electrical recordings of signals transmitted from the hippocampus suggested that the animals had developed place cells - cells that are believed to convey a sense of location - and that these cells were firing when an animal passed through a familiar place.

"Their place cells were less precise and less stable, but they were present and active," said Clark, who is also a research scientist at Veterans Affairs San Diego Healthcare System. "That was a surprise because we had removed the spatially modulated grid-cell input to these neurons."

The axons of grid cells project into the hippocampus and it has been assumed that without this relay of information from the entorhinal cortex to the hippocampus, place cells would be unable to develop. "This is not the case," he said.

"Our work shows a crisp division of labor within memory circuits of the brain," he said. "Removing the grid-cell network removes memory for places but leaves completely intact a whole host of other important memory abilities like recognition memory and memory of fearful events."

Co-authors include Jena Hales, Magdalene Schlesiger, Jill Leutgeb and Stefan Leutgeb, UC San Diego; and Larry Squire, Veterans Affairs San Diego Healthcare System and UC San Diego

This work was supported, in part, by the National Institute of Neurological Disorders and Stroke (1R01NS086947-01), National Institute of Mental Health (MH24600 and MH020002-13) and the Department of Veterans Affairs.

Scott LaFee | EurekAlert!
Further information:
http://www.ucsd.edu/

More articles from Life Sciences:

nachricht The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences

nachricht Transforming plant cells from generalists to specialists
07.12.2016 | Duke University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>