In a first-of-its kind study conducted at the University of Toronto and the Krembil Neuroscience Centre, researchers implanted electrodes in a specific part of the brain already known to be involved in depression and other mood disorders.

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Designed for stroke patients and those suffering from brain or spinal cord injuries, these so-called medical micropower networks (MMN) use a set of implanted electrodes and a wearable wireless controller to stimulate the muscles of a paralyzed user.

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After extensive trials on monkeys, he has now studied four human patients who each have had an array of 100 tiny electrodes implanted in their brains.

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Previous research has shown that visual and tactile information can be fed into and out of a rat's brain using microscopic electrodes implanted in the cortex -- most recently when the animals learnt to "feel" invisible infrared radiation.

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In a treatment undertaken after more than ten years of drug therapy had failed, around 100 electrodes were implanted in the woman's brain.

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The device consists of a panel of electrodes that are surgically implanted in the eye, and a pair of glasses with an attached camera.

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