Neurodevelopment: Unlocking the brain
Much of our neural circuitry is fixed during childhood. Researchers are finding ways to unglue it, raising hopes for treating many brain disorders.
Some of the interesting points that need highlighting – critical periods.
“Language acquisition is just one of many processes that go through a ‘sensitive’ or ‘critical’ period — an interval during development when the neural circuits responsible for that process can be sculpted, and radically changed, by experience (see ‘Open and shut’). During critical periods, children can make rapid progress at discerning facial features that look like their own, recognizing spoken language and locating objects in space. But within a few months or years, each window of opportunity slams shut, and learning anything new in that realm becomes difficult, if not impossible.”
But there may be opportunities to prise this open again … though in my experience this remains significantly difficult and involves a process of “retraining” the brain or looking for detours around in a conventional therapeutic / educational role.
“David Hubel and Torsten Wiesel, neurophysiologists at Harvard Medical School in Boston who carried out work on the visual system in the early 1960s. First they discovered that in the adult brain, many cells in the visual cortex respond to signals from only one eye. Then they showed that in kittens that had had one eye sutured shut, individual cells that normally would have fired in response to the closed eye instead responded to the open eye, eventually causing amblyopia1. Shutting the eye of an adult cat did nothing, indicating that cells in the visual cortex were programmed during a key developmental window in the first few months of life.”
The following is significant in terms of real treatment and outcome if the correct environment and ‘training’ work together. The length and intensity of “re-ducation” is significant pragmatically and needs to be further explored
“People develop amblyopia when problems such as cataracts or crossed eyes disrupt input to one of their eyes during early childhood, often leaving them without three-dimensional (3D) vision. The condition is considered untreatable once the critical period has ended. But when Li and Levi got people with amblyopia to play 40–80 hours of video games with their good eyes patched, most of them reported substantial improvements in visual function8. Describing one subject who was born with crossed eyes and had never seen the world in depth, Li says: “Once she found out she was able to see some 3D, she immediately began to cry.”
A couple of interesting points in regards to autism appear in the latter half of the article.
Such research makes it easy to imagine pills or shots that could aid recovery from a severe brain injury, for example, or make it easier to learn a new language or forget a terrifying memory. Lifting plasticity brakes might even be useful in treating complex disorders such as autism, says Hensch. He points to the difficulty children with autism have integrating input from multiple senses at once — when looking at a person’s facial expressions while listening to them speak, for example. Such integration may require the critical periods for each sense to have occurred in a specific developmental sequence. “I think that autism is a good example of what can go wrong when these different sensory critical periods are mistimed,” he says — a view for which there is some experimental evidence10.
The article concludes with some cautionary points
“When you reopen a critical period, there is, of course, always the possibility of a worse outcome,” says Alvaro Pascual-Leone, a neurologist at Harvard Medical School”
“I think it’s a romantic notion that you can replicate the critical period later in life,” he says. “Some things just don’t unhappen.”
Very interesting research for any number of reasons – pragmatically it is an ongoing where education / therapy may meet hard science at a molecular level to give better outcomes for ASD children.
Many of the difficulties that educational facilities and parents / caregivers could be alleviated by closer alliances and sharing of knowledge in what initially seem disparate disciplines.
I have always been an advocate of an etiological framework to built around intervention and special needs. This further amplifies this message.