In his groundbreaking 2009 New Yorker article on solitary confinement as torture, Atul Gawande described a researcher in the 1950s who raised a group of baby Rhesus monkeys in complete isolation from one another. While they grew up physically healthy, the monkeys “were also profoundly disturbed, given to staring blankly and rocking in  place for long periods, circling their cages repetitively, and mutilating  themselves.”

Nearly identical behaviors have, of course, been observed in humans subjected to solitary confinement, both anecdotally and by researchers like Stuart GrassianCraig Haney, and Terry Kupers, among others. Grassian described a specific psychiatric syndrome that affects prisoners in prolonged solitary, that includes symptoms such as hypersensitivity to external stimuli; perceptual distortions, illusions, and hallucinations; panic attacks; difficulties with thinking, concentration, and memory; intrusive obsessional thoughts; overt paranoia; and problems with impulse control. The effects of solitary on young people, with their still-developing brains, are presumed to be even worse.

Now, according to an article on LiveScience, scientists have uncovered new information on precisely how isolation affects the brain. Reporting on findings published in the latest issue of the journal Science, LiveScience’s Stephanie Pappas writes:

Social isolation in youth may wreak havoc on the brain by disrupting a protein crucial to the development of the nervous system’s support cells, new research finds.

A new study in mice finds that when the animals are isolated during a crucial early period, brain cells called oligodendrocytes fail to mature properly. Oligodendrocytes build the fatty, insulating sheathes that cushion neurons, and their dysfunction seems to cause long-lasting behavioral changes.

Research in rhesus monkeys and humans has shown that social isolation during childhood has an array of nasty and lifelong effects, from cognitive and social problems in neglected children to working memory troubles in isolated monkeys. These children and monkeys also show abnormalities in the white matter of the brain, which includes support cells such as oligodendrocytes as well as the fat-covered neural projections that act as the brain’s communication system.

But while previous studies had noted a correlation between white matter problems and cognitive struggles after isolation, they could not prove one caused the other.  Gabriel Corfas, a professor of neurology and otolaryngology at Boston Children’s Hospital and Harvard Medical School, and his colleagues wanted to understand how the relationship works. They took baby mice from their mothers at 21 days of age, right after weaning. Some of the young mice were put in typical laboratory conditions, living in a cage with three other mice. Another group was given an enriched environment, with lots of mousey company and an ever-changing array of toys. The final group of mice was put in individual isolation for two weeks, never seeing another rodent.

At 50 days of age, the mice were tested for sociability and working memory. In line with previous findings, the isolated mice struggled with both, while the enriched and normal-environment mice did fine. Soon after, the researchers examined the brains of all three groups for abnormalities.

They found no problems in the normal-environment and enriched-environment mice. But the animals that had been left all alone had strange, stumpy oligodendrocytes. These cells usually have long, complex projections (called axons) that reach out almost like tree roots. In the isolated mice, however, the oligodendrocyte projections were short and simple, without their usual complexity.

What’s more, the isolated mice had thinner protective sheathes around these neural axons, the projections that brain cells use to communicate. These sheathes, which are made of a fatty substance called myelin, help insulate axons and speed up neuron-to-neuron chatter.

The piece goes on to describe exactly how this damage to the white matter of the brain might be caused through changes in brain chemistry.  Corfas and his colleague found, among other things, that some of the changes “produced from isolation are also seen in patients with bipolar disorder and schizophrenia.”

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