The brain is a strange and remarkable machine. Not only does it control our dreams and thoughts, movements and decisions, but it stores all our memories and, ultimately, makes us who we are. It is made up of billions of nerve cells that transmit and receive information around the body. The brain is our own personal supercomputer and, just like those machines, it needs a lot of power – in fact, for a bit of human tissue that only weighs about 1.5 kilograms in an adult human (just 2 per cent of the body's weight), it uses approximately 20 per cent of the body’s energy supply. While our brains usually hum and process along just fine in support of our daily existence, sometimes things can go very wrong – whether from disease or injury. Here, we profile three York professors who are literally getting inside our heads and coming up with some surprising discoveries.
The Plastic Brain
New research sheds light on how our brains can relearn lost tasks
You might think your brain is hardwired from infancy, and that it remains pretty much unchanged throughout life, but new research both at York and abroad shows that’s far from the case. In York psychology Professor Kari Hoffman’s Perception & Plasticity (P&P) Lab, she and research colleagues are discovering our brains’ neurons are always changing and having new “conversations” with each other. Think of it as a giant cocktail party where new groups of people are constantly meeting, coming and going, and, in doing so, generating small cliques where fresh conversations are always springing up (even when we’re asleep) and information sharing is ongoing. It’s like a 24-7 meet-up.
Hoffman says many of the brain’s mysterious functions and dysfunctions lie in its ability to adapt and learn. Yet, she says, we know very little about how this learning happens in intact, living brains when all the parts are humming away in concord or – in the case of diseases such as Alzheimer’s or brain-damaged individuals – discord.
“We know now that injured brains can regenerate themselves and find new paths or different ways to do things,” says Hoffman. “That makes sense, because our brains are always looking for ways to maximize the results of incoming stimuli to process it better and faster. That means the output – movement, speech or whatever – will be more efficient.”
The P&P lab focuses on three essential areas: memory, perception and neural interactions. Hoffman’s research looks at how we perceive and process social signals – such as faces, voices, body parts and gestures – how we form our memories of them and even the role sleep plays in the way neurons talk to each other when the mind is at rest. Researchers have found that nighttime seems to be when memories of what we observed during the day are consolidated.
“The name of the game in our brain is about dynamics,” says Hoffman. “We clearly are not hardwired from birth and there are differences in how our neural networks talk to each other as we develop. We live in a world of objects, but what actually hits our eyes are wavelengths of light. But that’s not how we describe our surroundings. So how does the brain learn to differentiate subtle differences in, say, faces or different kinds of boxes – perhaps a wood one versus a cardboard one? Smaller or bigger? It’s incredibly complex. And even the best computer software has big difficulties doing what our brains do effortlessly.”
Hoffman says her research is all about trying to figure out how our brains do this so effortlessly. What she’s found is our brains’ neural networks actually seem to talk to each other. “We think these cliques allow us to process information faster and more efficiently and that helps reduce the background noise that you might have if you had millions of neurons all responding individually,” says Hoffman. “It’s a bit like a piece of music. If the right parts of the brain are sent the right information at the right times the rhythm of the music flows. But if the wrong signals are sent for processing the flow of the music is disrupted. That’s what we mean by the brain’s plasticity. We think that timing-based plasticity – the way neurons change the tune as it were – is by their timing with each other.”
Essentially, Hoffman listens to the conversations people’s brains are having via their neural networks using magnetic resonance imaging. She looks at these networks both when they’re being stimulated (in experiments) and afterwards when the brain is at rest, but still busy processing and sorting what it’s seen hours earlier.
Hoffman likens the challenges in her work to listening in on the conversations among a whole football stadium of people: “Imagine you care about each individual in that stadium and what he or she is saying among people close to them or further away. And then what fans of the other team are saying and, finally, what various cliques of fans on both sides are saying.”
Ultimately, Hoffman’s work could have far-ranging implications for people with Alzheimer’s disease, she says. “If we can find the right stimulation parameters for the brain’s “good” smooth rhythms that could have a big impact on helping improve Alzheimer’s patients’ memories in the future.”
Studying the effects of concussion
Ever since she was a kid, York kinesiology & Health Science Professor Lauren Sergio was always keen on sports and physical activity. “Basically, if it involved movement and jumping around, I was into it,” she states flatly. She’s been lucky enough in her life path to combine that passion with a brilliant mind that she was able to translate into a university research career. Although not a kid anymore, these days Sergio’s interests still concern movement, but in this case how the body’s biomechanics are involved with concussions, how to detect early-onset Alzheimer’s symptoms and how to develop tests that may be instrumental in assessing the extent of both conditions.
If Sergio hadn’t got hooked on biology she probably would have ended up a physical education teacher, she says. “But luckily I took a course in my undergrad years where we were looking at the brain’s control of movement. And I thought ‘Wow, this is cool.’ So I got a job in that prof’s lab and one thing led to another and now I am researching how the brain combines thinking and movement.”
Sergio is particularly interested in how the brain is affected by concussions and what that means for the ways in which it processes movement after the event.. To that end, she recently received a Canadian Institutes of Health Research grant worth $472,549 to study the effects of thinking and moving simultaneously in people who have had a concussion or are at risk of dementia (through early signs of cognitive decline or family history).
In Ontario, concussions have been on a steady rise. Statistics for 2002-05 show a large increase in the age group 11-18 in particular. Why this is so is unclear, says Sergio. “It may be increased competition and hitting in sports or better reporting of injury.”
What is clear from research, however, is that concussive injuries to the brain are cumulative, she says. “Once you’ve had one and get another, the effects are worse and last longer. And there’s evidence that repeated concussion cause long-term damage.”
The biggest challenge facing concussion researchers is to develop some kind of test that can identify with certainty, the severity of and/or recovery from concussions. Current tests tend to look at movement and thinking skills separately in injured brains, but Sergio says that’s not how humans live their lives: “We move and think at the same time in most cases. So tests that calibrate skill levels separately post-trauma really aren’t giving us an accurate picture for at-risk patients, particularly those with a family history of Alzheimer’s or those who have already suffered concussions.”
One of the big questions for athletes or anyone injured on the job (for example, a construction worker) is when is it the right time to go back safely to work or the hockey rink? The problem arises when injured players are given the all-OK because the separate tests results indicate injured players are problem free, says Sergio. However, when the brain is asked to multi-task, Sergio’s experiments show that injured brains perform more poorly than non-injured ones. “Performance just drops off when you ask people who have had concussions to do tasks that require both thinking and moving simultaneously,” she says, “even though if you asked them to do separate tests that just look at one or the other they’d perform just fine.”
The reason for this apparent anomaly is that our brains are masters of figuring out ways to overcome setbacks, like an injury. “Even if you’ve had a concussion years earlier, it will show up on our test results,” says Sergio. “But in the meantime, the brain has figured out how to ‘bypass’ the injury. So that’s a real challenge when trying to design tests that measure thinking and moving together in a way that is sensitive enough to not be tricked by [a person’s brain] compensation strategy.”
Sergio’s ultimate goal is to develop the research into a validated, clinically proven and feasible cognitive-motor assessment tool that can improve return-to-play safety, detect early signs of dementia and possibly even predict who will progress to full-blown dementia.
“It’s clear that the old ways of measuring brain function aren’t working,” says Sergio. “We need to find a new model, new ways of investigating how our brains are functioning and, if they can recover, to see if there are things we can do to help speed up that process. Our work with dementia isn’t preventative – we can’t undo genetic predisposition – but our research can contribute to heightening awareness. If you’re struggling, maybe there are things about your environment or the way you do things that can be changed to make your brain’s multitasking easier. That’s something we hope to find out.”
Can learning to dance help people with Parkinson’s?
A York research team, led by neuroscience and Psychology Professor Joseph DeSouza and Rachel Bar, a retired professional ballet dancer and now a clinical psychology student at Ryerson University, has embarked on a novel line of research – to see if learning to dance, or learning a specific dance routine, can improve motor control in people with Parkinson’s disease (PD).
PD is a neurological disease and degenerative disorder of the central nervous system that severely inhibits movement, currently affecting more than 100,000 Canadians. The motor symptoms of Parkinson’s result from the loss of dopamine-generating cells in a region of the midbrain; the cause of this cell death is unknown. Early in the course of the disease, the most obvious symptoms are movement-related, including shaking, rigidity, slowness of movement and difficulty with walking and gait. Later, cognitive and behavioural problems may start to arise, with dementia occurring in the advanced stages of the disease. Depression is the most common psychiatric symptom. Parkinson’s disease is more common in older people, with most cases occurring after the age of 50.
“While working on research involving dance – but not specifically in relation to Parkinson’s – we came across some articles that mentioned how dance seemed to help some people with PD,” says DeSouza. “One thing led to another – including a large donation to our lab from Irpinia, an Italian social club – providing the financial means to do research into dance as a means of PD therapy.
DeSouza gained access to dancers from the National Ballet of Canada through Rachel Bar, a graduate of Canada’s National Ballet School’s full-time professional program who is currently completing her master’s degree in clinical psychology at Ryerson University.
It has been known for some time that singing can help people who stutter, and DeSouza says there was previous evidence that learning to dance (which is also associated with rhythm and melody) seems, similarly to singing, to have an ameliorative effect for sufferers of Parkinson’s.
“The goal is to test the hypothesis that the brain can develop new paths around damaged areas if stimulated in certain ways,” says DeSouza. “In this case, we’re stimulating the brain using music and dance. We’re hoping that learning simple dance movement sequences can help improve Parkinson’s sufferers’ mobility.”
DeSouza’s research team is using York’s own magnetic resonance imaging (MRI) equipment located in the Sherman Health Science Research Centre to scan the brains of National Ballet of Canada dancers and Parkinson’s patients before, during and after learning a dance routine. The focus of the research is to see how their respective brains work and, in the case of Parkinson’s sufferers, to see how their brains might be able to develop new paths around damaged areas.
The MRI measures blood flow to different areas of the brain to determine how various areas respond to learning movements. York researchers monitor the neural circuits (medial frontal areas) that focus on the sequencing of movements. Also, by looking at these areas of the brain in professional dancers, they hope to conduct further research to figure out dance therapies for patients.
Volunteers for the study will come from the 12-week dance program for people with Parkinson’s at Canada’s National Ballet School (NBS), which begins this fall. Known as Dancing with Parkinson’s at NBS, the school is collaborating with the Mark Morris Dance Group’s Dance for PD program, based in New York City, and other local professionals.
While, as DeSouza noted, there have been other studies highlighting the usefulness of dance as a form of PD therapy, they have all used measures of analysis taken outside the body to track improvements. “The neural mechanisms behind those positive effects of dance for people with PD are still not understood,” he says. “Our study aims to address that gap in the literature by specifically studying changes in brain activity and structure that result from people with PD participating in dance classes.”
Courtesy of York U magazine