News reports of research into memory December 2007

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December 2007

Labeling facilitates categorization

I was delighted to see this report, since it supports an important piece of advice I offer about learning: that labeling your clusters is really helpful. A series of experiments has revealed that learning names for unfamiliar items really does make it easier to learn to categorize them — even though the labels were nonsense words and added no information to what was already known. Moreover, this occurred only with verbal labels; nonverbal associations didn't help.
The study appeared in the December issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2007-12/afps-lko120407.php

Songbirds offer clues to highly practiced motor skills in humans

A study of singing in the Bengalese finch has revealed information about motor skills that may benefit human performers and people needing motor rehabilitation. The tune of songbirds is a complex skill, achieved over a long period of practice as juveniles, and culminating in a highly stereotyped, stable song. But it turns out to be not as fixed as was thought. Adult songbirds, it seems, rely on auditory feedback to maintain their song. This study found that providing disruptive auditory feedback to a subset of the vocalizations almost immediately produced an appropriately targeted change in the bird's song. The study also found that really big changes could also be produced, but it had to be done incrementally, in small steps.
The finding was reported in the 20 December issue of Nature. Full reference
http://www.eurekalert.org/pub_releases/2007-12/uoc--soc122107.php

Early lead exposure impedes later recovery from brain injury

We know that lead exposure in early years can affect the brain. We also know that it increases the risk of various disorders later in life. Now a rat study reveals that animals exposed to lead earlier in life were significantly less able to recover from an induced stroke than those not so exposed. The study only looked at a short time-frame, so it is not yet known if the lead-exposed animals would catch up in their recovery in a longer period of time. There was some recovery in the lead group, but then it leveled off. The control group continued to get better. The findings support the suggestion that lead poisoning impairs neural plasticity.
The report appeared in the November issue of NeuroToxicology. Full reference
http://www.eurekalert.org/pub_releases/2007-12/tju-jnf120307.php

Young chimps top adult humans in numerical memory

A new study shows that young chimpanzees have an extraordinary working memory capability for numerical recollection—better than that of human adults tested in the same apparatus, following the same procedure. The study involved three pairs of mother and infant chimpanzees (all of whom were already versed in Arabic numerals) and university students. The task involved various numerals from 1 to 9 being briefly presented on a touch-screen monitor. Those numbers were then replaced with blank squares, and the subject had to remember which numeral appeared in which location and touch the squares in the appropriate order. The young chimpanzees could grasp many numerals at a glance, with no change in performance as the time that the numbers remained on the screen varied. Their performance was generally better than that of their mothers. The adult humans were slower than all of the three young chimpanzees in their response, and also showed the expected relation of poorer performance as duration got shorter. The young chimps’ memory ability may reflect eidetic imagery (the ability to retain a detailed and accurate image of a complex scene or pattern) — an ability seen in some human children before it declines with the age.
The report appeared in the December 4th issue of Current Biology. Full reference
http://www.eurekalert.org/pub_releases/2007-12/cp-yct112807.php

Fragile X retardation syndrome corrected in mice

In another study targeting the glutamate receptor mGluR5 (see September report), researchers have fixed multiple defects in fragile X mice by reducing these receptors by 50%. They achieved this through genetic engineering, but drugs blocking mGluR5 receptors are now entering human clinical trials. Fragile X is the most common form of inherited mental retardation and a leading identified genetic cause of autism.
The work was reported in the December 20 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2007-12/cp-fxr121407.php
http://www.eurekalert.org/pub_releases/2007-12/miot-mci121407.php

High blood pressure associated with risk for mild cognitive impairment

A study of nearly 1000 older adults (average age 76.3) without mild cognitive impairment at the start of the study found that over the follow-up period (average: 4.7 years), 334 individuals developed mild cognitive impairment, of which 160 were amnestic (reduced memory) and 174 were non-amnestic. Hypertension (high blood pressure) was associated with an increased risk of non-amnestic mild cognitive impairment; but not with amnestic mild cognitive impairment.
The report appeared in the December issue of Archives of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2007-12/jaaj-hbp120607.php

Brain systems become less coordinated with age, even in the absence of disease

An imaging study of the brain function of 93 healthy individuals from 18 to 93 years old has revealed that normal aging disrupts communication between different regions of the brain. The finding is consistent with previous research showing that normal aging slowly degrades white matter. The study focused on the links within two critical networks, one responsible for processing information from the outside world and one, known as the default network, which is more internal and kicks in when we muse to ourselves. “We found that in young adults, the front of the brain was pretty well in sync with the back of the brain [but] in older adults this was not the case. The regions became out of sync and they were less correlated with each other.” However, older adults with normal, high correlations performed better on cognitive tests. Among older individuals whose brain systems did not correlate, all of the systems were not affected in the same way. The default system was most severely disrupted with age. The visual system was very well preserved.
The results were published in the December 6 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2007-12/hhmi-tab120307.php
http://www.eurekalert.org/pub_releases/2007-12/hu-bsb120307.php
http://www.eurekalert.org/pub_releases/2007-12/cp-co112907.php

Cognitive therapy useful in treating post-traumatic stress disorder in early stages

A study of 248 adults with early symptoms of post-traumatic stress disorder (PTSD) following a traumatic event that had occurred no more than four weeks earlier (ie before PTSD can be formally diagnosed) compared 12 weeks’ treatment of either cognitive therapy (which helps people change unproductive or harmful thought patterns), cognitive behavioral therapy (which helps desensitize patients’ upsetting reactions to traumatic memories), an antidepressant (selective serotonin reuptake inhibitor) known to be helpful in treating chronic PTSD, placebo or no intervention at all. It was found that symptoms of PTSD were significantly less severe in those who received cognitive therapy or cognitive behavioral therapy compared to those treated with medication, placebo, or no treatment at all.
The study was presented at the American College of Neuropsychopharmacology (ACNP) annual meeting.
http://www.eurekalert.org/pub_releases/2007-12/acon-ssp120707.php

Some brain injuries may reduce the likelihood of PTSD

A study of combat-exposed Vietnam War veterans shows that those who suffered injuries to the amygdala or the ventromedial prefrontal cortex were less likely to develop post-traumatic stress disorder than those who suffered damage in other areas or had no head injuries (in fact none of those whose amygdala was damaged developed PTSD). The findings suggest that treatment designed to inhibit the activity of these two areas might provide relief from PTSD.
The results appeared online December 23 in Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2007-12/nion-sss122107.php

Brain-injured war veterans show a faster decline in cognitive functioning as they age

A study of Vietnam war veterans who suffered brain injuries during the conflict has found that the men show a faster decline in their cognitive functioning as they grow older than veterans without such injuries. Greater intelligence and a higher level of education before the injury was sustained were associated with a smaller decline in cognitive functioning — perhaps because of a greater number of neural connections, enabling the brain to recover better from injury.
The findings were published online 19 December in Brain. Full reference
http://www.eurekalert.org/pub_releases/2007-12/oup-bwv121707.php

Orphaned children fare better in foster care than in institutions

A study of 136 abandoned children from six institutions in Bucharest, Romania, has been looking at the question of whether there is a "best time" when intervention can help prevent these children from psychologically damaged. The children were randomly assigned to either remain in the institution or be placed into foster care (note that at this time the political preference was for institutionalized care). A third group of children, reared by their biological families in Bucharest, served as a control group. The researchers found that by age 4 1/2, youngsters in foster care were scoring almost 10 points higher on IQ tests than the children left in the orphanages. Children who left the orphanages before age 2 saw an almost 15-point increase. Every extra month spent in the orphanage, up to almost age 3, meant roughly a half-point lower score on those later IQ tests. Children raised in their biological homes still fared the best, with average test scores 10-20 points higher than the foster-care kids.
The study was published in the December 21 issue of Science. Full reference
http://www.eurekalert.org/pub_releases/2007-12/uom-ocf122107.php
http://www.physorg.com/news117382963.html

Neural substrate of congenital amusia

Research has shown that musicians have more gray matter in certain regions of the brain involved in language and auditory processing. Now a study of tone-deaf people reveals that congenital amusia, thought to be due to a severe deficit in the processing of pitch information, is also associated with differences in gray matter distribution. Tone-deaf individuals had a thicker cortex in the right inferior frontal gyrus and right auditory cortex. This may be due to abnormal neuronal migration or atypical cell pruning during development.
The study was published in the November 21 issue of the Journal of Neuroscience. Full reference
http://www.physorg.com/news117303842.html