Human Nature

The patients couldn't produce physical activity, as you or I would. But they could produce mental activity. They could use the brain as a kind of tablet, writing "tennis" on their supplementary motor area or "navigation" on their parahippocampal gyrus. That's the real genius of the European study: The mind can use the brain as a communication device.

Before brain scans, this was impossible. Nobody could see your brain. Thinking was one thing; doing was another. Scans have abolished that distinction. They have illuminated the paradoxical world of cognitive acts.

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