MAGNETIC pulses used to stimulate the brain could have a profound effect on the treatment of epilepsy, stroke, depression, schizophrenia and Parkinson’s disease.
New research from the University of WA and France’s Université Pierre et Marie Curie tested repetitive transcranial magnetic stimulation (rTMS) on mice to help better understand human neurological conditions.
Research Associate Professor Jennifer Rodger, from UWA’s School of Animal Biology, said magnetic fields have been used since the 1980s.
“A study showed that by stimulating specific parts of the cortex using a magnetic field, an electrical field is induced in the brain which then causes muscle contraction in specific areas of the body,” she said.
“This technique was used to map the cortex and is still used in stroke patients to see which parts of the cortex are no longer working. It was then taken further when researchers noticed that if you give multiple pulses, long-term changes in brain excitability occur, outlasting the duration of the pulses.
“This was thought to have great potential for therapeutic purposes and is now used in many neurological conditions and mental illnesses but there’s little understanding of how it actually works.”
A small copper coil was attached to a pulse generator to deliver pulsed magnetic fields, roughly the size of a mouse’s head. Perth company Global Energy Medicine provided magnetic field generators, usually used to treat musculoskeletal disorders, for the research.
While the mice used in Associate Professor Rodger’s work were not a model of human disease but did have abnormal connections in the brain. Knockout mice, which do not express the axon guidance molecules ephrin-A2 and ephrin-A5, were used.
“That means during development of these mice, the neurons in the brain don’t have any signposts to tell them where to go, so they make some correct connections but also a lot of incorrect connections,” Associate Professor Rodger says.
“We measured the accuracy of connections by electrophysiology and anatomical tracing techniques and showed the number of inaccurate connections was reduced by about 50 per cent. We also measured mice behaviour which improved and correlated with the improvement we saw in their brain connectivity.”
Similar studies have been carried out on humans to treat depression and Professor Rodger’s team is now submitting grant applications to measure how stimulation protocols affect excitability in the human brain.
“The next step will be studying how rTMS can affect the injured brain and we hope our studies will contribute to improving clinical procedures in the next two to three years,” she says.
