AP Biology class blog for discussing current research in Biology

Tag: spine

Loneliness Is Bad For The Brain

This new study from the Thomas Jefferson University in Philadelphia suggests that loneliness can have quite an impact on the brain. The study is based on the effects of social isolation on mice. The mice were raised together where they could play with each other and form social ties. Then they were separated from each other for months on end. The results were quite interesting.

File:Coronal section of a mouse brain stained with Hematoxylin & LFB.jpg

Cross Section of Mouse Brain

After about a month of isolation, the mice developed more “spines” on their dendrites. This is peculiar because this development would usually happen as a response to a positive stimulus. The researchers theorize that the brain is trying to save itself from the loneliness. But this effort is not long lived. After three months of isolation, the brain returns to baseline levels of neural activity. The brain also has reduced amounts of a protein called BDNF, responsible for neural growth. They also found increased amounts of the stress hormone cortisol. Lonely mice also had more broken DNA than their socialite counterparts.

Although it is not known how the results of this study can relate to the brains of humans it may shed some light into the lesser known effects of loneliness on the brain. It also brings into question the effect incarceration could have on a person long term and whether or not it could be more harmful than rehabilitating. What do you think about this study? What could the results of a similar test on humans yield?

Spinal Neurogenesis

An astrocyte cell grown in tissue culture as viewed by Gerry Shaw

Normally, when spinal neurons are lost during life due to disease or injury, they are lost for good, however, thanks to a recent study done by  Zhida Su and his colleagues at the University of Texas Southwestern Medical Center that may no longer be the case. The team took astrocytes—star-shaped support cells in the nervous system— from the spines of living mice and converted them into neurons. This research was based of the previous works of  Marius Wernig from the Stanford University School of Medicine, who first converted rat skin cells into stem cell like cells and then into neurons, Benedikt Berninger from Ludwig Maximillians University Munich, who took certain brain cells and turned them into neurons, and Olof Torper from Lund University, who transformed astroytes from the brains of mice into neurons. Su and his team were drawn to spinal astrocytes because they form scar tissue after spinal cord injuries.

Su and his team accomplished this transformation by injecting a series of viruses into the mice, one of which, SOX2, managed to convert the spinal astrocytes into neuroblasts, both in culture and in living mice who had suffered spinal injuries. Some of these neuroblasts then went on to form functioning neurons and with the addition of valproic acid the number of cells which matured doubled and actually interacted with existing motor neurons.  Although this process is slow and can take up to four weeks, it is incredibly promising and it is even suggested that, “For each reprogrammed [cell], perhaps more than one new neuron could be generated,” meaning that each neuroblast could divide and create multiple neurons. Although this research is extremely promising, only 3-6% of astrocytes effected become neuroblasts which has been in no way enough to study the effects on the health of the mice. However, this research is very young and could lead to major achievments in neurogenesis in the future and the “curing” of paralysis and other conditions that result from the destruction of neurons.

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