Associate Professor, Division of Medical Sciences
Research area: cellular and molecular mechanisms of neuronal plasticity, diabetes and stroke research,
iInvestigation of higher-order information processing centers
It weighs just 3 pounds and is almost 80% water. Yet the human brain, which contains over 100 billion neurons, is constantly undergoing complex changes that are essential to processes that include learning, memory, and most importantly, self repair. How exactly this happens is still a mystery; one that Dr. Craig Brown hopes to solve.
Dr. Brown, a researcher and instructor in the University of Victoria’s Division of Medical Sciences, studies brain plasticity: the process by which the brain changes, constantly creating new connections between cells that are responsible for processing and transmitting massive amounts of information everyday.
Brown, a neuroscientist with a background in biological psychology, is looking at the structural and functional changes that occur in the brain on both a molecular and systems level. Specifically, he is working to generate valuable information that will help clinicians better understand issues relevant to their practice, including post-stroke brain recovery.
Prior to the 1960s, the commonly held belief was that the development of the brain was ‘fixed’ after childhood, incapable of further change or growth. Scientists now know that when brain cells are damaged or destroyed, as they are during a stroke, the brain re-wires itself over time, essentially rerouting incoming and outgoing information, so that some level of function can be regained.
While scientists understand that the degree of brain plasticity is closely associated with the level of function recovered following a stroke, what they do not know is why some people are more or less likely to recover than others. Diabetics, for example, have an increased risk of stroke and a less than optimal prognosis for successful recovery, when compared to non-diabetics.
Currently, Dr. Brown is spearheading an innovative research program that focuses on brain plasticity and its role in associative learning, the ‘use-it-or-lose-it’ phenomenon of brain function, and post-stroke recovery. Using fluorescence-based imaging techniques, Brown studies the brains of mice, particularly the changes that are occurring in their brains before and after significant experimental events.
Recently, Brown’s lab set out to learn why the brain loses responsiveness to parts of the body that have not been sufficiently used over time, a phenomenon better known as ‘use-it-or-lose-it’, and the basis behind the idea that reading or working on mind puzzles, such as Sudoku, keeps your brain sharp.
In order to explore this concept, Brown trimmed a couple of facial whiskers in mice (which they use to sense their environment) and then imaged how their somatosensory cortex responded to the trimmed whiskers. He found that within just a couple of days, the somatosensory cortex became less responsive to stimulation of the inactive whiskers. He also discovered that this loss of brain responsiveness was directly regulated by a specific receptor within the brain, the alpha 4 nicotinic acetylcholine receptor.
Brown also uses brain imaging in mice to better understand how the brain makes simple associations and encodes new information. By conducting experiments that pair whisker stimulation with sound and food, while monitoring the structural and functional changes that unfold within the brain – essentially a neuronal Pavlovian-type response – Brown is generating new insights into processes involved in human learning.
One of the most compelling projects currently underway in Brown’s lab is aimed at understanding why stroke recovery is significantly limited in diabetics. By imaging brain maps before and after stroke (at various times), Brown and his assistants have discovered that the formation of new neural circuits following a stroke is impaired in the diabetic brain. Based on this discovery, he is now focusing on what molecules may be involved in this process. In particular, his lab is interested in how blood vessel related growth factors regulate blood flow, as well as the structural integrity and proliferation of new blood vessels in stroke affected regions.
The ultimate goal? If we can understand what mechanisms regulate neural circuit plasticity and the blood vessel networks that support them, we can then design intelligent treatment strategies to promote brain repair after stroke or other neuropathological conditions.
While Brown is hopeful that the information he is generating on brain plasticity will eventually translate into new clinical therapies, he concedes that these things take time.
“Medical breakthroughs come through basic science research. Generating knowledge is key,” says Brown.
Dr. Brown is also quick to acknowledge the valuable contributions made by his colleagues, research assistants, and funders, including CIHR, NSERC, CFI, MSFHR, and the Heart and Stroke Foundation of BC and Yukon.
With an extensive list of publications behind his name, and his lab’s most recent work on post-stroke brain recovery soon to appear in The Journal of Neuroscience, Brown and his colleagues are steadily assembling their own information scaffolding; scaffolding upon which future successes may be built.