Cognitive Labs

Evel Knievel (deceased Nov. 30, 2007) jumps the Snake River (Idaho) Canyon...

prototype for daredevil action adventure genre that created the six million dollar man...

Labels: brain, evelknievel, memory, snake

Besides helping you feel well-rested, getting your zzz's may also sharpen your memory, a new study shows.

Researchers found that sleep not only protects memories from outside interferences, it also helps strengthen them.

"There was a very large benefit of sleep for memory consolidation, even larger than we were anticipating," said study author Dr. Jeffrey Ellenbogen, an associate neurologist at Brigham and Women's Hospital, Boston, and a postdoctoral fellow in sleep medicine at Harvard Medical School.

The research is scheduled to be presented May 2 at the American Academy of Neurology annual meeting in Boston.

In the study, the researchers focused on sleep's impact on "declarative" memories, which are related to specific facts, episodes and events.

"We sought to explore whether sleep has any impact on memory consolidation, specifically the type of memory for facts and events and time," Ellenbogen said. "We know that sleep helps boost memory for procedural tests, such as learning a new piano sequence, but we're not sure, even though it's been debated for 100 years, whether sleep impacts declarative memory."

The study involved 48 people between the ages of 18 and 30. These participants had normal, healthy sleep routines and were not taking any medications. They were all taught 20 pairs of words and asked to recall them 12 hours later. However, the participants were divided evenly into four groups with different circumstances for testing: sleep before testing, wake before testing, sleep before testing with interference, or wake before testing with interference.

Two of the groups (the wake groups) were taught the words at 9 a.m. and then tested on the pairings at 9 p.m., after being awake all day. The other two groups (the sleep groups) learned the words at 9 p.m., went to sleep, and were then tested at 9 a.m.

Also, prior to testing, one of the sleep groups and one of the wake groups were given a second list of 20 word pairs to remember. These groups were then tested on both lists to help determine memory recall with interference (competing information).

The result: Sleep appeared to help particpants recall their learned declarative memories, even when they were given competing information.

According to the researchers, people who slept after learning the information performed best, successfully recalling more words whether or not there was interference. Those in the sleep group without interference were able to recall 12 percent more word pairings from the first list than the wake group without interference (94 percent recall for the sleep group vs. 82 percent for the wake group).

When presented with interference, those who slept before testing did significantly better at remembering the words (76 percent for the sleep group vs. 32 percent for the wake group).

"We were surprised to find the order of magnitude by which the data demonstrated our effects," Ellenbogen said.

Jan Born, a professor of neuroendocrinology at the University of Lübeck in Germany, said the study offers more proof of the importance of sleep for memory consolidation.

"Considering that learning in every educational setting (schools, colleges, etc.), is centrally based on hippocampus-dependent memory function [declarative memories], people should realize that optimal learning conditions require proper sleep," he said.

Proper sleep may have other benefits, too, added Michael Perlis, director of the Sleep Research Laboratory at the University of Rochester in Rochester, NY. Research has shown that in addition to memory, sleep may be related to physical functioning, good immune function, physical and cognitive performance, and mood regulation, he said.

"These are all theories. The only thing we know is that when we're deprived of sleep, we do less well. Is that a lack of sleep or sustained wakefulness? It's very difficult to figure out how to crack that nut," he said. "We spend 30 percent of our time on sleep. What is sleep for? This is a riddle we're still working on."

Labels: aans, memory, sleep

McGill University researchers have discovered that a mutant gene improves the long-term memory of laboratory mice, a discovery they hope will one day lead to a better quality of life for Alzheimer’s patients and others suffering from memory impairment.

"We now have an excellent target for the development of new drugs that would be capable of doing the same thing that we did, which could be of great benefit to an aging population with memory loss," said Dr. Mauro Costa-Mattioli, a post-doctoral fellow in the laboratory of Dr. Nahum Sonenberg, James McGill Professor of Translational Control Mechanisms in the Department of Biochemistry and a Howard Hughes Medical Institute International Scholar at McGill.

Using a mutant gene that regulates the switch from short to long-term memory in mice, Dr. Costa-Mattioli and his colleagues were able to manipulate biochemical reactions in the animals’ brains to control their memory and cognitive behaviour – both extending and reducing long-term memory functions. Their findings appear in the April 6 issue of the journal Cell.

To study spatial memory, the researchers used such tests as the Morris water maze, in which a mouse is placed in a pool of water containing a hidden platform located just below the surface. Visual cues are placed around the pool and over a number of trials, researchers analyze how quickly the mice remember how to locate the hidden platform using these cues. In this and other tests, the researchers found that the mice with the altered gene exhibited enhanced learning and memory.

Drs. Mauro Costa-Mattioli and Sonenberg conducted the research in collaboration with Dr. Jean-Claude Lacaille of Université de Montréal, Dr. Kobi Rosenblum of the University of Haifa and Dr. Randal Kaufman of the University of Michigan, as well as a team of colleagues from McGill, consisting of Drs. Jerry Pelletier, Wayne Sossin, Claudio Cuello, Kresimir Krnjevic and Karim Nader, a McGill psychology professor best known for his discovery that the impact of traumatic memories can be lessened with drug treatment.

"Our next step is to look at many different compounds to start searching for a drug that can be designed to improve long-term memory in humans," said Dr. Sonenberg.

Labels: alzheimers, McGill, memory, mice