Unlocking the Mind’s Mysteries
It’s been called the most complicated object in the known universe. But, as UT scientists are learning, the human brain offers five important clues for understanding its wonders.
By Marc Airhart. Illustrations by Jenna Luecke.
Brain researchers see your brain in all its astounding complexity. With 100 billion brain cells, or neurons, each having about 10,000 connections to other neurons, there are more connections in the brain than there are stars in our vast galaxy.
Amid the complexity, scientists in the Department of Neuroscience at UT Austin are slowly unraveling the brain’s best-kept secrets and offering hope for treating some of the most stubborn and debilitating afflictions. Here are five things they’ve recently learned.
1. Your brain changes over time, like wine.
Children are the masters of specific memories, recollecting details in ways that elude their parents. But what adults lack in specific memories they make up for in generalized ones. While children remember a birthday party’s specific decorations, guests and their costumes, the grownup remembers which of the party’s activities worked or didn’t – broad-stroke lessons that help in planning for next time.
“We’re trying to measure the emergence of wisdom,” says Alison Preston, associate professor of psychology and neuroscience. “What are the underlying neural mechanisms by which wisdom emerges?”
Recent research suggests that generalizations are formed at least in part in the front of the hippocampus, a part of the brain that doesn’t fully develop until adulthood. Using functional magnetic resonance imaging (fMRI), Preston monitors brain activity as people do memory and learning tasks and examines how differences in the way the tasks are described or information is presented might help children make generalizations that are key to conceptual learning.
“We can come up with good training strategies that might impact, down the road, how a teacher works with students of different ages,” Preston explains.
2. It’s an ace at prediction.
When Michael Mauk first saw videos of UT’s soccer-playing robots, he was struck by how often they fell down – nearly every time they kicked a ball or made a quick turn, in fact.
“You know, we don’t fall down because we have a cerebellum,” Mauk, the chair of the Department of Neuroscience, told Peter Stone, the computer science professor whose lab programs the soccer-playing robots for international competitions.
Since the early 1990s, Mauk has been building increasingly sophisticated computer simulations of the cerebellum, the part of our brain that handles motor memory and helps us move in precise ways. With inspiration from the simulations, he and Stone are developing a computerized cerebellum for the robots that can predict – and thereby prevent – falls.
This work also has implications for helping people with paralysis.
“My dream is that in 15 years, a paralyzed person could be fitted with an exoskeleton,” Mauk says, “and when they think, ‘I want to walk over there,’ the exoskeleton just does it. Part of the control system behind that would involve a computer cerebellum to make sure they don’t fall down.”
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3. It hums along like a computer.
Daniel Johnston, the Center for Learning and Memory’s director, was first trained as an electrical engineer. Neurons, he explains, are like computers that do the brain’s work – making and retrieving memories, learning and making decisions, perceiving stimuli – through the exchange of electrical signals.
In people with epilepsy, neurons work improperly, firing all at once. Johnston discovered that one of the ion channels, which ferries neurons’ electrical signals back and forth, is reduced in the brains of epileptics – and also seems to be disrupted in people with depression and Alzheimer’s disease. This suggests some drugs that target seizures may also help people with mental illness and dementia – something his lab is looking into.
“In all these diseases, the way cells fire is abnormal,” Johnston says. “So if we had a drug that worked effectively and specifically on these channels, then we could potentially work on a number of different disorders.”
4. It picks a frequency.
Brain cells share different kinds of information with one another using distinct types of waves, just as radio stations broadcast on specialized frequencies. Your brain uses one type of frequency to recall memories or make a plan and another when it processes an event that’s happening to you in the moment.
Laura Colgin, an assistant professor of neuroscience, discovered that the brain recalls memories and imagined thoughts using a particular brain wave frequency, called a slow gamma rhythm, whereas real-time experiences are stored on another frequency. She notes that people with schizophrenia may be experiencing disrupted gamma rhythms that make it hard for them to distinguish between imagined and real experiences.
“Maybe they are transmitting their own imagined thoughts or memories on the wrong frequency, the one usually reserved for things that are really happening,” says Colgin.
In a healthy brain, real-time events are recorded on the frequency that allows for rich details in high resolution, whereas memories, plans and imagination occur with gamma rhythms that allow scenarios to play out in the mind in fast-forward.
“Perhaps that’s why,” Colgin says, “you can plan out events and think about the sequences of actions you’ll do – or recollect something that happened – on a faster time scale than it takes to actually go and do those actions.”
5. Your brain is something like a worm’s.
At first glance, the roundworm C. elegans doesn’t have much in common with us. As long as a credit card is thick and possessing neither a heart nor lungs, it has just 302 neurons. Still, the tiny worm shares most genes responsible for the nervous system with us.
“We just seem so much more complex because we have so many more cells,” says Jon Pierce, an associate professor of neuroscience. “If humans and worms were both made of Legos, we’d be made of the same types, we’d just have a lot more of them.”
Pierce uses a genetically modified version of C. elegans to test drugs that might slow or prevent the death of neurons in patients with Alzheimer’s disease. (Pierce’s interest in Alzheimer’s is more than academic – his mother has the disease and both he and his teenage son have serious genetic risk factors.) As the worm ages, a specific neuron in the middle of the body dies, causing it to bend in a funny way. That telltale sign helps researchers see how the disease is progressing or slowing in response to interventions.
The worms also age very quickly, which helps researchers. As Pierce explains, “You can test an idea on Monday and know the results by Friday.”
Neuroscientists at UT Austin are also searching for ways to combat alcoholism and addiction. Adron Harris of the Waggoner Center for Alcoholism and Addiction Research, and his team mapped the differences in gene expression between an alcoholic’s brain and a non-alcoholic’s brain. They found that, as a person becomes dependent on alcohol, thousands of genes in their brains are turned up or down, like a dimmer switch on a lightbulb, compared to the same genes in a healthy person’s brain. The scientists are now using an innovative technique to find drugs that can help turn the metaphoric switches back to their original settings and, they hope, revert an alcoholic’s brain into a non-alcoholic brain. The work might help the millions of people who suffer with the emotional, financial and health consequences of alcoholism.
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