News reports of research into memory October 2005

For index of all headlines, go to News & Views main page

To look at research reports sorted by subject go to Research Reports

For news about Alzheimer's research go directly to the Alzheimer's page

You can find links to the journals referred to on this site here: Journal links

October 2005

Eating fish associated with slower cognitive decline

Analysis of data from an ongoing longitudinal study of older adults in Chicago has found that the rate of cognitive decline over a six-year period was reduced by 10-13% in those who ate fish at least once a week.
The study is available online on Archives of Neurology, and will be published in the December issue. Full reference
http://www.eurekalert.org/pub_releases/2005-10/jaaj-efa100605.php

Long-term smoking associated with dulled thinking and lower IQ

A long-term study involving 172 alcoholic and non-alcoholic men has found that long-term smoking impaired memory and reasoning skills and reduced IQ. The effect was most pronounced among those who had smoked for years. The effects of smoking were found among the non-alcoholics as well as the alcoholics, and among the alcoholics, the cognitive impact of long-term heavy smoking appeared to be greater than the impact of drinking.
The findings were released online before publication in Drug and Alcohol Dependence. Full reference
http://www.eurekalert.org/pub_releases/2005-10/uomh-dsc101005.php

Changes in brain, not age, determine one's ability to focus on task

It’s been established that one of the reasons why older adults may do less well on cognitive tasks is because they have greater difficulty in ignoring distractions, which impairs their concentration. But not all older people are afflicted by this. Some are as focused as young adults. An imaging study has now revealed a difference between the brains of those people who are good at focusing, and those who are poor. Those who have difficulty screening out distractions have less white matter in the frontal lobes. They activated neurons in the left frontal lobe as well as the right. Young people and high-functioning older adults tended to use only the right frontal lobe.
The study was reported in the September issue of Psychology and Aging. Full reference
http://www.eurekalert.org/pub_releases/2005-10/uoia-cib102605.php

Early life stress can lead to memory loss and cognitive decline in middle age

Age-related cognitive decline is probably a result of both genetic and environmental factors. A rat study has demonstrated that some of these environmental factors may occur in early life. Among the rats, emotional stress in infancy showed no ill effects by the time the rats reached adulthood, but as the rats reached middle age, cognitive deficits started to appear in those rats who had had stressful infancies, and progressed much more rapidly with age than among those who had had nurturing infancies. Middle-aged rats who had been exposed to early life emotional stress showed deterioration in brain-cell communication in the hippocampus.
Study results appeared in the October 12 issue of the Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2005-10/uoc--els100605.php

Concussions increase chance of age-related cognitive impairment

A study involving retired National Football League players found that they had a 37% higher risk of Alzheimer's than other U.S. males of the same age. Some 60.8% of the retired players reported having sustained at least one concussion during their professional playing career, and 24% reported sustaining three or more concussions. Those with three or more concussions had a five-fold greater chance of having been diagnosed with mild cognitive impairment and a three-fold prevalence of reported significant memory problems compared to those players without a history of concussion. As the study was based on self-reported answers to the health questions, further studies are needed to confirm the findings, but it does seem likely that head injuries earlier in life increase the chance of developing dementia or mild cognitive impairment.
The study appeared in the October issue of Neurosurgery. Full reference
http://www.eurekalert.org/pub_releases/2005-10/uonc-nsa101005.php

Shift in brain's language-control site offers rehab hope

Language activity in right-handed people is initially localized in the left side of the brain, but a new study shows that this gradually becomes a function shared by both sides. From ages 5 to 25, language activity increases in the dominant hemisphere; from 25 to 67, the nondominant hemisphere increasingly shares the load. The discovery gives new hope for rehabilitation of brain function in adults after stroke or traumatic brain injuries.
Their results will be published in the February 2006 edition of Human Brain Mapping.
http://www.eurekalert.org/pub_releases/2005-10/uoc-sib100605.php

Why autism is associated with executive function problems

A new imaging study has revealed that autistic boys have less activation in the parts of the brain responsible for executive function (attention, reasoning and problem solving) — specifically, in the caudate nucleus, a critical part of circuits that link the prefrontal cortex of the brain. The researchers have noted similarities in the impairment of specific executive function in children with ADHD and autism.
The results of this research are soon to be published in American Journal of Psychiatry.
http://www.eurekalert.org/pub_releases/2005-10/ra-ape102305.php

AIDS inflicts specific pattern of brain damage

A new imaging study has revealed a startlingly selective pattern of destruction inflicted by AIDS on brain regions. Only motor, language and sensory functions were affected. Also surprisingly, there was no difference in brain tissue loss between those taking antiretroviral drugs and those not. It appears that the blood barrier prevents these drugs entering the brain.
The study was published online on October 10 in the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2005-10/uoc--ais100605.php

Wnt signaling vital for adult neurogenesis

Neurogenesis (the birth of new neurons) only occurs in adult brains in two areas: the lateral ventricle, and the dentate gyrus (in the hippocampus). New neurons are spawned from the division of stem cells — but how do they decide whether to remain a stem cell, turn into a neuron, or a support cell (an astrocyte or oligodendrocyte)? A new study has pinpointed the protein that provides a vital chemical signal that helps this decision in the hippocampus. When Wnt3 proteins were blocked in the brains of adult mice, neurogenesis decreased dramatically; when additional Wnt3 was introduced, neurogenesis increased. Wnt3 molecules are secreted by astrocytes.
The study was published in the 27 October issue of Nature. Full reference
http://www.eurekalert.org/pub_releases/2005-10/si-wsc102405.php

Return to top