Magnetic brain stimulation may improve vision

7 August 2006

Peripheral vision may be improved by stimulating certain parts of the brain with brief electromagnetic pulses, according to research published today in the journal ‘Current Biology’ by a team at the UCL Institute of Cognitive Neuroscience.

The study used trans-cranial magnetic stimulation (TMS) to stimulate an area of the brain’s frontal cortex, which is  involved in generating eye movements, while activity in connected brain regions was recorded with a brain scanner.

TMS works by holding a magnetic coil next to the skull and moving it over the part of the brain to be manipulated. The magnetic fields created by the coil briefly induce small electrical currents inside the skull that alter the activity of neural pathways, stimulating or inhibiting activity in parts of the brain.

In the UCL study, the result of applying TMS was that brain activity in the visual cortex was enhanced, almost as though an eye movement had taken place and the brain was receiving visual information (although the eye itself stayed still). In perceptual tests, the participants were asked to compare the brightness of objects, presented on a computer monitor in the visual periphery or in the centre of the screen. The tests confirmed that, with TMS, the participants could see better out of the corner of their eyes.

The findings could mean that poor or damaged vision may one day be improved by applying TMS. Mr Christian Ruff, who led the research group, said: “The approach of combining TMS with brain scanning enables us to identify interactions between connected regions of the brain. Such information can be crucial for understanding and treating neurological disorders that can affect vision or other brain functions, for example after strokes. Our specific findings and our approach may be very relevant for developing therapeutic uses of TMS.”

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