Solitary confinement is about placing individuals in –most of the time- typical 6x9 cells and forcing them to remain isolated from other humans for twenty-three hours per day. The one hour that they may be able to leave their cells, they will be placed again in an outdoor empty cell or cage where they will be all alone. It’s the so-called recreation time.
Officials strongly claim that this kind of imprisonment is not torture, since no physical harm is caused to the individuals. The physical harm that officials do cause to people held in solitary is another issue. But, is really solitary confinement not affecting physically the individuals? Science does not quite agree…
The effects of social isolation have long been detected. Psychosis, paranoia, sleep deprivation, aggression are only a few of the symptoms that several species face when they are isolated. In the past years though, scientists are trying to find the biological basis of all these effects. Guess what, they are all connected with our brain and disorders that appear after Social Isolation Stress (SIS).
In a recent study by Zelikowsky et al. (2018), it was proved that a two-week SIS in mice induced aggression, reduced the social interaction with other mice, increased interaction with predators (rats), and caused hypersensitivity to footshock. They also proved that compared to group-housed mice, the SIS mice had increased freezing-time following an ultrasonic sound or a loom disk which represented a predator. When trying to discover the biological basis of all these isolation-induced symptoms, they found that the gene Tac2 played a key role.
Tac2 is one of the roughly 25,000 genes that exist in the cell nuclei of the mice. Although they exist in every cell of their body, they are mostly expressed in their central nervous system. They are responsible for the synthesis of a neuropeptide, a small protein in the brain, called NkB. NkB then binds to a receptor, Nk3R, in different regions of the brain. This binding causes a signaling cascade which eventually leads to the expression of more genes that affect social and emotional behavior.
What these scientists found was that mice that were socially isolated for two weeks, overexpressed the Tac2 gene, which led to an over-synthesis of the NkB neuropeptide in several different regions of the brain. In each region, it caused different responses to SIS. Also, when the scientist used osanetant, a molecule that does not let NkB bind to their receptors and thereby stops the signaling cascade induced by the NkB-Nk3R binding, most of the SIS symptoms vanished.
Interestingly, a gene with a similar role has been found on Drosophila melanogaster, one of the most commonly used laboratory animals. This fact implies that this gene does not only exist in mice or other similar species but in fact, it looks like it’s a highly-conserved gene among species. So, why we, humans, mammals as well, should be much different from mice?
These kinds of experiments are very difficult to be conducted to humans but strong evidence implies that we share similar mechanisms. We should now probably wonder; is actually solitary confinement not causing physical trauma, when it is proved by several studies that it alters the brain? A bruise might fade away after a couple of weeks, but will a brain ever be able to recover after months and years of social isolation? Remember, the mice were only isolated for two weeks. Most prisoners will consider themselves lucky if they remain in solitary confinement for a month.
Reference
Zelikowsky, M., Hui, M., Karigo, T., Choe, A., Yang, B., Blanco, M. R., Anderson, D. J. (2018). The Neuropeptide Tac2 Controls a Distributed Brain State Induced by Chronic Social Isolation Stress. Cell, 173(5), 1265–1279.e19. doi:10.1016/j.cell.2018.03.037
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