This therapy could dramatically help stroke victims by unlocking paralysed arms and legs and restoring much of their lost mobility.
Dr Clarkson (31) is the co-author of a study describing the discovery - made during tests involving mice -which was published this week in the online edition of Nature, the international scientific journal.
The study also provides hope for those with traumatic head injuries, given the brain mechanisms of repair are similar, so the new approach could also work for them, Dr Clarkson says.
Six weeks of treatment of mice reactivated neurons in the brain responsible for limb function, producing dramatic results, with an extra 50% of gross motor limb mobility consistently gained, the study found.
One compound - known to enhance cognition and initially developed to treat Alzheimer's disease - is already being trialled in people with learning difficulties.
Animal studies have already shown big improvements in limb mobility, and Dr Clarkson believed memory and learning could also be "greatly enhanced" for many stroke victims through use of this class of drugs, known as "extrasynaptic GABA inverse agonists".
Current compounds tended to crystallise out in the kidney after a week of use, making them inappropriate for prolonged use by humans.
He believed this problem could be overcome fairly quickly by drug companies, and a compound could be developed within two years which would be suitable for clinical testing.
Dr Clarkson is a research fellow at the Otago University departments of psychology and anatomy and structural biology.
He is also an Otago pharmacology graduate, who late last year returned to Otago University from postdoctoral studies at the University of California, Los Angeles.
He planned to undertake further animal study work, including exploring the potential to enhance memory and learning.
Strokes were the leading cause of adult disability, and the third leading cause of death in New Zealand and other developed countries.
Strokes also had a "huge flow-on effect" on victims and their families, including depression experienced by some injured people who had lost their ability to work, and reduced income for the wider family, he said.
Annual spending on stroke care throughout the world amounted to hundreds of billions of dollars, including more than US$60 billion in the United States alone.
Late last year, Dr Clarkson was awarded the Health Research Council's Sir Charles Hercus Fellowship ($500,000 over four years) to support his research.
