Though the patch clamp electrode allowed neuroscientists to study electrical signals from inside neural cells, it is a tool with very limited capabilities. No more than about a dozen cells at a time can be studied, but the brain and the neural system operate on much larger scales. To help study entire neuronal networks comprising thousands of interconnected cells, researchers at Harvard University have created an electronic chip on which neurons can grow while their electrical activity is closely monitored. The technology has already allowed the team to create synaptic connectivity maps with hundreds of unique connections.
On top of the chip is an array of nano-scale electrodes that are so fine that they don’t cause much damage to cells. To motivate the cells to let the nanoelectrodes puncture their membranes, current is passed through the electrodes. Signals from the neurons placed on top of the chip are then automatically boosted thanks to a built-in amplifier within the chip.
The team showed off the capability of their chip by recording more than 1,700 rat neurons in parallel. Using twenty minutes of neural recording, they were able to spots hundreds of synaptic connections. To demonstrate the potential of the technology for studying drugs, the team exposed the cells to a number of drugs to see what effects they had on ion-channel currents.
Study in Nature Biomedical Engineering: A nanoelectrode array for obtaining intracellular recordings from thousands of connected neurons