Watching Babies' Brains Develop
London Times (July 9, 2000)
Sarah is a six-month-old baby, sitting on her mother's lap, watching television. Nothing unusual in that, except that she is wearing what looks like a hairnet covering an old-fashioned perm - Ena Sharples before a night out.
"It's actually a geodesic net," explains Leslie Tucker of the Centre for Brain and Cognitive Development at Birkbeck College, London. "It records tiny electrical frequencies from 64 points on Sarah's scalp. It lets us see what is going on in a baby's brain in a way that has not been possible before."
The net is providing valuable insights into how children learn, as well as revealing surprising things about the brains of people with autism. Eventually, it may help to unravel the hugely complex ways in which genes and environment interact.
We are all familiar with those oval scans of the adult brain, with areas glowing in bright, artificial colors, showing which parts are active when you are talking or frightened or thinking about sex. For years, neurologists have wanted to build similar maps of the activity in a baby's brain.
During the first two years of life, brain cells grow and wire themselves up at an incredible rate - at the age of two, children have 150% more connections between their brain cells than adults.
"We can't use normal methods to peer into babies' brains," says Professor Mark Johnson, the director of the center. "Some involve radioactivity or strong magnetic fields, which could be harmful. They also require you to stay very still for long periods in a steel tube - not the kind of thing you can persuade a six-month-old to do." Now the hairnets, which hang on a wall in the Birkbeck lab like miniature fishing nets, could revolutionize the study of babies' brains. With a little practice, they can be slipped over a baby's head in a single move, and each soft sensor within the net starts recording immediately.
Johnson's team has already made several discoveries about the way that babies respond to faces. "We've known for some time that adult brains have a special 'face' area," he says, "but until recently nobody knew if it emerged fully formed when you were born or if it was wired up gradually, and if so, how?"
Earlier research by Johnson had shown that from the moment it emerges, a baby is primed to respond to anything that is remotely face-like - three dots arranged in a triangle will do. "We know that adults have a much harder time recognizing a face if it is upside-down," he says. "So we wanted to know if babies were the same."
Using the net, his team has found that six-month-old babies don't make as big a distinction between upright and inverted faces as adults. A possible reason is that the baby responds to individual features rather than the arrangement of the face. By a year old, however, the net shows that babies respond to inverted faces in a more adult way.
A surprising spin-off from this research is a discovery about the way that adults who are autistic process faces. Autism is a neurological disorder that means sufferers are very poor, among other things, at responding socially. They are often withdrawn and appear to spend little time looking at other people's faces, so researchers had predicted they would also be poor at recognizing them.
"One idea is that they would be more likely to concentrate on features, as six-month-olds seem to," explains Sarah Grice, a PhD student seconded from the Institute of Child Health. "But when we tested them with the net, something quite different emerged." Adults with autism had much the same difficulty with upside-down faces as normal adults.
A bigger surprise was the way adults with Williams Syndrome - another neurological disorder - process faces. They are poor at matching ordinary patterns, but are very social and good at recognizing faces, so the prediction was that they would process faces in an adult way. The net showed the reverse. They responded with brain patterns closer to those of six-month-old babies. "We are not sure what is going on," Grice says, "but we may have to rethink our ideas about these disorders."
The net has also revealed that, while adults most often use the right side of the brain for recognizing faces, young children and people with Williams Syndrome use the left and right sides together.
The net is helping the Birkbeck group to ask fundamental questions about how the brain develops, which may have big implications for the way we treat newborns. Take, for instance, the Zero to Three lobby, strong in America and becoming popular in the UK. The idea is that, because so much brain development goes on between nought and three, it is vital for children to be stimulated and taught from a very early age, as brain cells that are not wired up might then be lost for ever. Use it or lose it, runs the argument.
Johnson's studies suggest this is a mistake. "Newborn babies have a powerful drive to learn," he explains. "They actively contribute to their own brain development. For example, we've estimated that by four months, a baby will have made more than 3m eye movements, which go to establishing patterns in their higher visual centres." Extra stimulation is a waste because babies are programmed to stimulate themselves as necessary.
Ultimately, the net may contribute to understanding the fiendishly complex dance that goes on between genes and environment to wire up the brain. "People still think in terms of a nature/nurture divide," Johnson says. "Either the brain is programmed to wire up in a certain way or it responds to the environment. Our work with the net supports the notion that there is a third way."
It seems that, from the beginning, we all have a strong drive towards certain basic behaviour, such as looking at faces or listening to the human voice. "But the responses you get determine how the higher centers of your brain get wired up," Johnson says. "So, if you hear Japanese, you lose the ability to distinguish certain sounds - such as between R and L. If you were brought up by monkeys, your brain would have a different set of responses from someone who is surrounded by human faces."
Johnson believes there are probably critical periods when the brain needs the right inputs. "Some brain disorders may arise because something went wrong with the basic drive that should have helped stimulate the higher centers," he says. "The good news is that the net has shown how plastic the early brain is, so once we have identified that problem, it may be possible to provide the necessary stimulation artificially."
The Birkbeck unit is looking for volunteers. If you have a healthy baby less than a year old and live in the London area, call 020 7631 6258.
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