August 27, 2018

Department of Biomedical Physiology & Kinesiology

(Sensorimotor Neuroplasticity)

Joined SFU in January 2017

Dr. Cooke’s innovative research program explores links between variation in brain organization and behaviour, response to injury, and the brain’s capacity to rewire itself. In laboratory experiments, variation between individuals has almost always been regarded as a complication to be minimized and thus, very little is known about individual variation in brain organization. Dr. Cooke aims to characterize and study the significance of this variation, determining how it affects skilled behaviour, resilience in the face of brain injury, and natural, adaptive changes in the brain.

What was your path to an academic career in science?
I had incredible science teachers in middle school who encouraged my curiosity by finding opportunities for me like running my own experiments on gravity. As a teenager I became interested in big questions like the origin of the universe and the biological basis of consciousness. In university I took a psychology course with Dr. Charles Gross, who is known for discovering individual neurons that specialize in detecting complex visual stimuli like hands and faces. I asked for a job in his lab and he gave me a project recording single neuron responses. From then on, I was hooked.

What topics are you researching?
I'm interested in how the brain is organized, how it is shaped by experience, and how its organization shapes behaviour.

My group studies the variation that exists among brains. Ultimately, this variation is what makes us individuals with different preferences and abilities. We’re focusing on one particularly variable part of the brain, the motor cortex, and creating detailed maps of its organization so that we can study how individuals differ.

We use a number of techniques to do this, such as electrically stimulating the brain to evoke movement or reversibly deactivating part of the brain by cooling it – i.e., temporarily removing it from the circuit – in order to probe the function of a given area. We combine data sets to create a layered map of brain organization to explore how the brain changes with experience, what the limits of that plasticity are, how much variation exists among individuals, and the significance of that variation.

Why was brain variation ignored for so long, and what did the early studies look like?
If you are studying anything else about the brain then variation is your enemy – it is noise in your data. There have been virtually no systematic studies focused on variation in brain organization and how that relates to behaviour.

Individual brain variation has been mentioned in papers going back decades, often as an aside. For example, some papers that map the organization of a brain region show maps for multiple individuals rather than an average, composite brain, and you can always see obvious differences among individuals. It is something that all neuroscientists know about and is mentioned but it is not the main focus of the studies. My research program takes a new perspective by addressing the importance of individual brain variation and how it relates to behaviour.

Why do you create multi-layered brain maps?
One layer of data is what we call a “motor map”, obtained when you stimulate different points in the motor cortex to identify which muscles are activated. If we want to understand how the pattern in one individual is related to another layer, e.g. connections in the brain, it is not useful to align an individual’s motor map to an average map of connections for that species. To understand brain variation, we need to align data sets from the same individual.

The value of each individual’s data set is enhanced when you layer it with another type of data set from the same individual because each one provides context for the other. Motor maps tell you about function whereas cellular structure shows you where the borders are between brain areas, which also vary between individuals. We combine these maps to understand how function relates to brain areas.

We can layer multiple data sets from an individual, like a motor map layered with a sensory map, the cellular brain structure map, the connection map, and functional data maps based on reversible deactivation data. Combining data sets is difficult, but the combined data set tells us a lot more about how the brain works.

Once you create multi-layered maps and use them to characterize the variation between individuals, where does your research go from there, and what downstream applications do you envision?
We know that when animals or humans practice a skill, it causes that function to take over a larger part of the brain – the ‘representation’ of that function expands. This increases the processing power devoted to that function and allows the individual to improve their ability to perceive sensory information or make a coordinated movement. That’s how we become better or faster with practice.

We know that brains vary between individuals in significant ways. We know that brains change as we learn skills. I want to ask whether different variations in brain organization give an advantage in learning those skills; in other words, do certain variants demonstrate faster learning or respond better to different kinds of practice? In the future this could potentially allow someone to tailor their practice to their starting brain organization in a way that leads to greater skill.

An intriguing potential application relates to the recovery from brain injury. What if certain brain variants are more resilient to brain injury? For example, a stroke victim with damage to a certain area of the brain could experience faster recovery or a smaller deficit to begin with if the representation of the affected body parts is more distributed across their motor cortex or that region is larger to begin with. If so, we might be able to protect brains by training them into patterns of organization that will fare better in the case of a stroke.

What educational backgrounds and personal strengths do you look for in prospective trainees?
I'm looking for students who are curious, excited about learning new skills, and who may have experience with coding or working in a lab. My program is suited to students with an undergraduate degree in biomedical physiology and kinesiology, psychology, biology, molecular biology and biochemistry, or even computer science or engineering.

As a new faculty member, what sort of projects will your first graduate students undertake?
Initially, we will build a system for rapid brain mapping. This will involve assembling hardware and writing software such that we can use feedback from muscle activity to fine-tune the stimulation applied during experiments. This system will allow us to accelerate our data collection and create much more detailed brain maps. Students in my group need to be comfortable wearing many hats in terms of animal work, histology, assembling hardware, programming, and troubleshooting.

How is your lab set up?
I share a large, newly renovated lab space containing a surgical suite and a wet lab with two other researchers, neurokinesiologist Dr. Andy Hoffer, who applies his expertise in neural control of movement to developing rehabilitation techniques and neural prostheses, and Dr. Steve Reynolds, a research-active critical care physician. Our research programs are distinct but there is overlap in some of the techniques we use. Having colleagues with rich physiological expertise in complementary areas enriches the training environment and accelerates the pace of our research.


Read more: Dr. Cooke’s profile on the Department of Biomedical Physiology & Kinesiology website, his Banting Research Foundation profile and interviews with other faculty members on the Featured Researchers page

Interview by Jacqueline Watson with Theresa Kitos