Sleep Key to Better Memory For New Skills
Want to really remember something you learned? Get a full night's sleep. According to two recent studies, the brain molds newly-learned information into lasting memories most successfully while we rest.
Both studies show that well-rested individuals learn new skills most easily, particularly when they sleep soundly the first night after new learning. Researchers at Harvard Medical School in Boston tested sleep's impact on procedural memory (memory for task-related information) by teaching subjects a visual target task. Following their first exposure to the targets, one group slept normally while another stayed awake all night.
Although all subjects slept normally the following two nights before re-testing, only those who slept on the first night improved on the task -- proving the impossibility of "catching up" on lost sleep.
Early stages of sleep are also important in the learning process, as emphasized by research at the University of Lubeck in Germany. Researchers found that the first three hours of sleep are crucial to retaining recently-learned skills. During this phase, known as "slow-wave" sleep, the brain establishes connections that make memories permanent.
Both studies appear in the December issue of Nature Neuroscience (2000;3:1237-1238, 1335-1339), and conclude that restless or shortened sleep inhibits learning and retention.
Hypnosis Fails to Show Improvement in Memory Performance
Contrary to popular belief, hypnosis does not improve our memory of past events. While hypnosis does influence confidence in recollections, it does not improve their accuracy.
Researchers at Ohio State University in Lima tested the effects of hypnosis on memory by placing 48 subjects under hypnosis while another 48 performed relaxation exercises. Each group was given 20 minutes to identify the month and year of 20 noteworthy events, asked how confident they were in their responses, and given their tests back. They were told they had at least one wrong answer and were allowed to make corrections.
Lead author Joseph Green, associate professor of psychology at Ohio State, notes that "the relaxation group and the hypnotized group were equally accurate--or equally inaccurate." As reported at the 2001 American Psychological Association's meeting in San Francisco, no difference existed between the groups' confidence in their accuracy. However, just 17% of hypnotized students revised answers, while 25% from the relaxation group made corrections.
Even when hypnotized subjects reported low confidence, they remained unlikely to alter their responses. This "implies a greater trust in their original answer," Green said, and also implies faith in the power of hypnosis to enhance accuracy. However, the relaxation exercise might decrease confidence, making hypnosis subjects seem comparatively more certain.
Chewing Gum May Improve Memory
If your cognitive skills aren't at their best, you may just need a stick of gum to boost your brain power. Research at the University of Northumbria and the Cognitive Research Unit in Reading, England, shows that the repetitive chewing motion positively influences thinking, memory, and other mental tasks.
In the experiment, 75 subjects underwent a 25-minute test of various types of memory. Those who had chewed real gum showed better performance throughout the test as compared to those who had not chewed gum or had only pretended to chew. The heart rate of gum chewers was slightly faster than in other groups.
Andrew Scholey of the University's Human Cognitive Neuroscience Unit presented his team's findings at the 2001 British Psychological Society's annual conference in Blackpool. He explained that "the mild increase in heart rate may improve the delivery of oxygen and glucose to the brain, enough to improve cognitive function."
Additionally, chewing gum induces a surge of insulin due to the mouth watering in anticipation of a meal. "It is known that there are insulin receptors in areas of the brain important for learning and memory," Scholey said. Overall, he believes that "the results were extremely clear and specifically we found that chewing gum targeted memory."
Paying Attention When Learning Is Essential to Remembering
Focusing one's attention on the act of processing and absorbing information can actually make remembering easier, say scientists at University College London . Their findings were reported in the December 1999 issue of the journal Science.
Using MRI to evaluate brain activity, they discovered that the brain cannot learn information when attention is indirect. Participants in the study showed excellent ability to recall information they had concentrated on, but were unable to recall information they had not paid attention to ,even if they had been looking right at it. For the brain to successfully process information and form memories, focused attention is necessary.
CLINICAL TRIALS UNDERWAY FOR MEMORY-RESTORING DRUG
Age-related memory loss, ranging from the occasional "senior moment" to the devastating dementia of Alzheimer's disease, is currently an unavoidable part of the future for 40% of aging individuals. Soon, though - thanks to a little red pill -- such problems may be no more than memories themselves.
Nobel laureate Eric Kandel, famed for his illuminating study of the molecular workings of memory, recently presented findings from research at the Howard Hughes Medical Institute at Columbia University. According to Kandel, . "There are metabolic disturbances in the brain with age-related memory loss and one can, in the mouse, reverse those changes," he said. "I think it's quite likely that human therapies will become available for age-related memory loss over the next five years."
Kandel's current research shows memory cells to be in a constant state of interaction with one another - a state enhanced through repetition. Information that runs repeatedly through the "neural circuitry spread over hundreds . . . or thousands of cells" in the brain creates a stronger pattern than a single experience of that same information, making memories stronger and more lasting.
The experimental pill acts on memory circuits in the brain by topping off levels of certain chemicals that can lock newly formed patterns of recall into place. "They really work as a replenishment of substances that decrease (over time) from their normal amounts," Kandel said in a presentation at the Australian Neuroscience Society Annual Meeting.
NEW FEEDBACK TECHNIQUE ENHANCES MEMORY
People can be trained to control specific frequencies of brain activity while subduing others -- consciously improving memory function. As reported in the International Journal of Psychophysiology (2003;47:75-85), "neurofeedback" may benefit people suffering from hyperactivity, epilepsy, and other cognitive disorders, and can also enhance working memory in healthy individuals.
The memory-boosting method utilizes EEG sensors placed on the scalp to measure neural activity. These feed information back to the individual through a game displayed on a computer screen. To control the game, one must learn to control various brain-activity frequencies through relaxation and focused attention.
Researchers at Imperial College London observed 40 medical students playing 15-minute intervals of the game twice a week for four weeks. A subset of subjects learned to consciously increase their sensorimotor rhythm activity (SMR), which correlated with improvements in recall. Boosting this brain frequency coincided with a jump from 71% initial recall of a list of words to 82% after training. Subjects trained to enhance other brain frequencies did not significantly improve on this task.
This study supports other clinical findings suggesting neurofeedback's cognitive benefits. "This the first time we have shown a link between the use of neurofeedback and improvements in memory," lead researcher Dr David Vernon said. Whether the relationship between SMR and recall was causal or merely an association, and whether observed improvements were permanent, remains to be seen.
Vitamins Help You Remember to Take Your Vitamins
A vitamin-rich diet can defend against Alzheimer's, the degenerative disease that currently afflicts over 4 million elderly US citizens. Recent research suggests that B-vitamins promote cell health and mental acuity.
Researchers at Karolinska Institute in Stockholm, Sweden tracked 370 individuals over age 75 for three years. As published in the journal Neurology (2001;56:1188-1194), results show that low blood levels of vitamin B-12 and folate double the risk of Alzheimer's disease.
Head researcher Dr. Hui-Xin Wang suggests that levels of a harmful protein called homocysteine may spike following a drop in B-vitamin levels. Homocysteine damages nerve cells, possibly leading to the cognitive decline characteristic of Alzheimer's disease.
B-12 vitamins are known to promote nerve cell health, and previous research has shown a significant correlation between low B-12 levels and Alzheimer's disease. Folate, another B-vitamin, has been associated with healthy cells. Prior to the Sweden study, however, little research had examined folate's role in staving off Alzheimer's disease.
Wang and colleagues believe that monitoring B-vitamin levels in the elderly could help doctors diagnose Alzheimer's, and vitamin supplements could prevent levels from dropping too low. Good sources of B-12 include milk, meat, fish, and eggs. Leafy green vegetables, dried beans and peas, and citrus fruits are naturally rich in folate, and many cereals are fortified with a synthetic version of the important vitamin.
Healthy Diet improves Memory and Cognition
As more and more people live past age 70, understanding the relationship between diet and cognition becomes imperative. A healthy diet can stave off age-related dementias, according to a recent study.
The National Research Council in Milan, Italy examined 1600 individuals over age 70. Subjects filled out food questionnaires and were tested for mental functioning. Researchers calculated nutrient intake and ranked each subject on cognitive performance.
As reported in the December 2001 issue of the European Journal of Clinical Nutrition (2001;55:1053-1058), low saturated fat and cholesterol, a healthy balance of nutrients, and moderate drinking correlated with less cognitive decline. All subjects showed adequate intake of fruits and vegetables, although women's diets included healthier levels of protein and cholesterol. Close to one third of the men and half of the women studied showed cognitive decline.
While it is not clear how a healthy diet promotes good cognition, antioxidants like vitamins C and E may be the key. Antioxidants clear damaging particles from the body, and have protective effects against heart disease, cancer, and other chronic disorders like Alzheimer's disease. Omega-3 fatty acids found in fish may also keep cognitive functioning intact.
Study leader Dr. ML Correa Leite believes more research is necessary before specific recommendations about diet and cognition can be made.