Dr Clarkson, a research fellow in the university departments of psychology and anatomy and structural biology, was commenting during Brain Day activities at the university on Saturday.
Four university speakers, Dr Clarkson, Dr Liana Machado, Dr Graeme Hammond-Tooke and Dr Louise Parr-Brownlie, gave free public lectures during Brain Day, which was part of international brain awareness week.
The Dunedin activities were hosted by the university Brain Health and Repair Research Centre, in association with the Neurological Foundation of New Zealand.
Dr Clarkson noted that some brain cells were killed in strokes, but recent research suggested that some nearby cells previously thought to have also been killed were, in fact, merely "silent".
These cells could potentially be reactivated, helping to boost functional recovery.
He noted that the main treatment used after stroke was physical therapy.
Patients embarked on a "long, hard process" in order to regain some normal limb function.
In a study involving mice, published in Nature last year, Dr Clarkson and colleagues at the University of California, including neurologist co-author Dr Thomas Carmichael, found that a drug compound, part of a class of drugs known as "extrasynaptic GABA inverse agonists", could unlock paralysed limbs, with an extra 50% of gross limb motor mobility gained.
Clinical trials in humans could start within two years, but the drug needs some further development work to avoid known side effects in kidneys.
In a wide-ranging address, Dr Clarkson also discussed the possibility of enhancing aspects of the body's production of stem cells to boost some of the brain's natural repair mechanisms.
He also emphasised the importance of swift initial response to strokes.
In the case of ischemic strokes, which blocked blood and oxygen supply to part of the brain, clot-busting drugs could be safely administered only within four and a-half hours of a stroke.
