Fifty nanoscale devices on a chip measure electrical signals traveling along a single neuron. (Credit: Lieber Group, Harvard)

Tiny changes in the way electrical signals move through neurons are the basis of learning and memory--and of many brain pathologies. But it has been difficult for neuroscientists to observe these changes in much detail. Now, researchers at Harvard University have created a tool with unmatched sensitivity: silicon nanowires that amplify very small electrical signals from as many as 50 places on a single neuron. Existing methods can pick up signals from only one or two places.

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