When a pregnant woman uses cocaine, it can interrupt the flow of nutrients and oxygen to the baby, putting such children at risk for premature birth, low birth weight and many other problems. However a new review of 32 major studies of school-age children reveals that the consequences for the brain are less sweeping than feared. Although many of the children did have low IQ and poor academic and language achievement, this seems to be related more to the home environment.
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Data from more than 20,000 18-year-old Israeli men has revealed that IQ scores are lower in male adolescents who smoke compared to non-smokers, and in twin brothers who smoke compared to their non-smoking brothers. The average IQ for a non-smoker was about 101, while the smokers' average was about 94, with those who smoked more than a pack a day being lower still, at about 90. 28% of the sample smoked one or more cigarettes a day, 3% identified as ex-smokers, and 68% said they never smoked.
An analysis technique using artificial neural networks has revealed that the most important factors for predicting whether amnestic mild cognitive impairment (MCI-A) would develop into Alzheimer’s within 2 years were hyperglycemia, female gender and having the APOE4 gene (in that order). These were followed by the scores on attentional and short memory tests.
The first comparison of the brain sizes of social and non-social individuals of the same species provides more support for the social brain hypothesis (we evolved our big brains to deal with social groups). The tropical sweat bee species, Megalopta genalis, have two sorts of queen: solitary ones, who themselves go out from the nest to forage for food, or social ones — who stay at home and sends out her daughters.
An imaging study involving 79 volunteers aged 44 to 88 has found lower volumes of gray matter and faster rates of decline in the frontal and medial temporal lobes of those who ranked high in neuroticism traits, compared with those who ranked high in conscientious traits. These are brain regions particularly affected by aging. The idea that this might occur derived from the well-established effects of chronic stress on the brain. This is the first study to investigate whether the rate and extent of cognitive decline with age is influenced by personality variables.
An imaging study has revealed that children (aged 5-15) whose mothers abused methamphetamine and alcohol during pregnancy had structural abnormalities in the brain that were more severe than those seen in children whose mothers abused alcohol alone. In particular, the striatal region was significantly smaller, and within the group, size of the caudate correlated negatively with IQ. Limbic structures, in particularly the cingulate cortex and the right inferior frontal gyrus, were significantly bigger.
A 12-year study following the drinking and smoking habits of 22,524 people aged 39-79 has found that in non-smokers, people who consumed moderate amounts of alcohol were 37% less likely to develop stroke than non-drinkers. This association was not found among smokers. The finding may explain the inconsistency in previous studies into the relationship between light to moderate drinking and stroke.
Data from over 900 community-dwelling older adults participating in the Rush Memory and Aging Project has found that greater purpose in life was associated with a substantially reduced risk of developing Alzheimer's disease, as well as a reduced risk of mild cognitive impairment and a slower rate of cognitive decline. Specifically, those scoring in the top 10% of a purpose in life measure (4.2 out of 5) were approximately 2.4 times more likely to remain free of Alzheimer's disease than individuals in the bottom 10% (score of 3.0).
Examination of the brains from 9 “super-aged” — people over 80 whose memory performance was at the level of 50-year-olds — has found that some of them had almost no tau tangles. The accumulation of tau tangles has been thought to be a natural part of the aging process; an excess of them is linked to Alzheimer’s disease. The next step is to work out why some people are immune to tangle formation, while others appear immune to the effects. Perhaps the first group is genetically protected, while the others are reaping the benefits of a preventive lifestyle.
A rat study shows how Ritalin improves concentration and, it now appears, speed of learning. The study reveals that it does this by increasing the activity of dopamine at two specific types of neurotransmitter receptors in the amygdala. The dopamine receptor tagged “D2” appears to control the ability to stay focused on a task, while the D1 receptor underlies learning efficiency. The finding may help the development of better-targeted drugs.