Zapping brain with magnetic pulses 'may prune bad wiring'

London, Feb 19 (ANI): Exposing the brain to weak magnetic pulses removes unwanted neural connection in mice, and this can be used for treating conditions associated with abnormal neural circuitry like schizophrenia in humans, a new study has claimed.

In magnetic stimulation through the cranium, a magnetic coil brings about electric currents in the brain, which can strengthen or suppress neural connections.

This technique has proved to be successful in improving symptoms in people with brain disorders like autism and depression.

Jennifer Rodger and her colleagues from the University of Western Australia in Crawley have found that stimulating the brain at intensity lower than a neuron fire can get rid of unwanted neural connections in mice at least.

As children, human brains produce too many connections between cells, but as we develop, some connections are snipped while others are strengthened. Incompetent pruning has been implicated in schizophrenia.

The researchers used genetically modified mice with abnormal connections in an area of the brain called the superior colliculus (SC), which is involved in motion detection.

In these mice, 90 percent of the axons in the SC had extended into the wrong areas. These bad connections make it very difficult for them to follow moving objects in their line of sight.

Rodger used low-intensity, pulsed magnetic field stimulation (PMF) on the rodents' SC for 10 minutes a day for more than two weeks. It is thought that PMF is too weak to make healthy neurons fire.

However, after treatment, tissue analysis showed that only 45 percent of the abnormal axons were still there.

"The axons that weren't in the right place were wiped out," New Scientists quoted Rodger as saying.

After receiving the treatment, the mice were also better at tracking objects.

"PMF is awakening unwanted connections, so the brain can detect and remove them," Rodger said.

Unwanted neurons generally express high levels of a specific NMDA glutamate receptor.

According to Rodger, Unwanted neurons, which generally express high levels of a specific NMDA glutamate receptor, makes them sensitive to changes in electrical activity and so even low-intensity pulses can activate these neurons.

NMDA receptors send out signals that trigger the recruitment of two chemicals called nitric oxide and brain-derived neurotrophic factor (BDNF), which help to remove abnormal circuitry in healthy brains.

They found that modified mice given PMF expressed higher levels of both chemicals, while only minor changes were found in healthy mice or those given a sham procedure.

"I think it is a very promising avenue for treatment of nervous system disorders that involve abnormally abundant and inaccurate connections," Rodger added.

The study has been published in The FASEB Journal. (ANI)