Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers use new method to probe recollections in memory-impaired patients

05.02.2008
Neuroscientists continue to debate whether or not long-term memory always depends on a region of the brain called the medial temporal lobe, which contains the brain’s memory-processing center, the hippocampus. A new study of brain-damaged patients by researchers at the University of California, San Diego (UCSD) School of Medicine readdresses the issue using a new method to elicit more detailed long-term memories.

The study, led by Larry R. Squire, Ph.D., professor of psychiatry, neurosciences and psychology at UCSD School of Medicine and research career scientist at the San Diego Veterans Affairs Health System, supports the theory that remote, or very long-term, memory remains intact after the medial temporal lobe is damaged. The results will be published in the early on-line edition of Proceedings of the National Academy of Sciences the week of February 4-8.

In 2005, a study led by Squire and published in the journal Neuron, studied the ability of patients with selective brain damage to recall events in their past. The findings strongly suggested that the ability to recollect “remote autobiographic events,” or distant memories, gradually becomes independent of the medial temporal lobe as time passes.

However, proponents of an opposing theory – that retention of distant memories requires the continued involvement of the hippocampus – suggested that these findings were flawed because the measurement techniques used to elicit remote memories weren’t sensitive enough.

The PNAS study looked at the ability of patients with selective brain damage to recall events from their past using a new method, called the Autobiographic Interview, which uses extensive probing to elicit an average of 50 or more details per memory.

“Using this more sensitive testing method, we found that autobiographical recollection was impaired in patients with medial temporal lobe damage when memories were drawn from the recent past, but fully intact when memories came from the remote past,” said Squire.

The new approach used tape-recorded narratives of extended recollections and determined the number of details that patients produced about events from their early lives. The Autobiographical Interview was administered to three patients with limited hippocampal damage, two with large medial temporal lobe lesions and five controls without any brain damage. Participants were asked to provide one memory from each of five time periods: childhood to age 11, teenage years, early adulthood, middle age and the year immediately prior to testing.

“Each of the amnesic patients was able to provide detailed autobiographical memories, with an average of 50 details per memory, from the three most remote time periods that were sampled,” said first author C. Brock Kirwan, Ph.D., postdoctoral fellow in UCSD’s Institute for Neural Computation.

Previous methods looked at a larger number of remote memories, prompting recollection of approximately 20 details per memory. Kirwan theorized that earlier studies elicited fewer details because it is difficult to produce a large number of details when asked about 24 different episodes. “In any case, we have found remote autobiographical memory to be intact after medial temporal lobe damage, whether patients produce memories with more or fewer details,” he said.

The researchers also conclude that impairment to such remote memories that have sometimes been reported using the Autobiographical Interview or other tests is likely due to significant damage outside the medial temporal lobe.

Debra Kain | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Health and Medicine:

nachricht Researchers identify new way to unmask melanoma cells to the immune system
17.01.2018 | Duke University Medical Center

nachricht Study advances gene therapy for glaucoma
17.01.2018 | University of Wisconsin-Madison

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: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Polymers Based on Boron?

18.01.2018 | Life Sciences

Bioengineered soft microfibers improve T-cell production

18.01.2018 | Life Sciences

World’s oldest known oxygen oasis discovered

18.01.2018 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>