Why are some people more vulnerable to addiction than others? Scientists from The Scripps Research Institute may have an answer after their discovery of the key role of a particular type of genetic material in cocaine addiction. In animal studies, the scientists found that increasing the level of a molecule called microRNA-212 in the brains of test animals conveyed protection against addictive behavior. Conversely, a reduction in microRNA-212 in the brain raised addiction susceptibility.
What the new findings suggest is that individuals with serious addiction problems may have damaged supplies of microRNA-212, or the microRNA may not function properly.
With this knowledge it might be possible to develop a therapeutic that mimics or stimulates the production of this particular microRNA.
The study appears in the journal Nature. News release
Similarities found in bird and human brains
The brains of mammals have long been thought to be more highly evolved than the brains of other animals (such as birds) based, in part, upon the distinctive structure of the mammalian forebrain and neocortex — a part of the brain's outer layer where complex cognitive functions are centered.
A new study by UCSD School of Medicine researchers found that comparable regions of the brain, used by humans and chickens to analyze auditory signals, are constructed in a similar manner.
Sophisticated imaging technologies, used to map this region of the chicken brain, revealed that the avian cortical region is composed of laminated layers of cells with extensive interconnections that form microcircuits virtually identical to those found in the cortex of mammals. A practical outcome of this discovery could be the use of birds as a non-mammalian animal model in brain studies.
The findings are published in the Proceedings of the National Academy of Sciences. News release
Brain stem cells at rest
Stem cells in the brain remain dormant until called upon to divide and make neurons. However, little is known about what keeps them inactive. Now, scientists from the Salk Institute for Biological Studies have identified the signal that prevents stem cells from proliferating, thus, protecting the brain against too much cell division and ensuring a pool of neural stem cells that lasts a lifetime.
Researchers focused their attention on bone morphogenetic factor protein (BMP) and found BMP signaling in non-dividing cells, including dormant stem cells. Conversely, in proliferating cells BMP signaling activity was not detected.
Two brain regions harbor neural stem cells. One is the hippocampus, an area of the brain vulnerable to age-related degeneration. Regular physical exercise has been shown to slow the shrinking of the aging hippocampus and also to improve learning and memory in mature adults. Thus, new insights into adult stem cells regulation may ultimately help scientists understand the interplay between exercise, aging and neurogenesis.
The research appears in the journal Cell Stem Cell. News release