Harvard University has developed an electronic chip that can simultaneously record the synaptic connections of thousands of neurons
False-color SEM image of neurons cultured above an electrode array. The actual neurons were much denser, with three to six layers of cells covering the entire electrode array.
How do our brain cells, or neurons, use electrical signals to communicate and coordinate higher brain functions? This has been one of the biggest questions in science. For decades, researchers have used electrodes to monitor and record these signals. As an electrode placed in a thin glass tube, the patch clamp penetrates neurons and records synaptic signals within the cell. It revolutionized neurobiology in the 1980s, but the tool could only measure about 10 cells at a time and lacked the ability to record networks of neurons.
Now, researchers at Harvard University have developed an electronic chip that can simultaneously record the signals of thousands of connected neurons with high sensitivity. The breakthrough allowed scientists to map synaptic connections at an unprecedented level, identifying hundreds of them. The paper is in the journal Nature Biomedical Engineering.
"The combination of sensitivity and parallelism in this study can benefit both basic and applied neurobiology, contributing to the construction of functional connectome and high-throughput electrophysiological screening." Co-corresponding author of the paper, Mark Hyman Jr., professor of chemistry and physics. Say.
"This long-term parallelization of intracellular records enables the mapping of biological synaptic networks and provides a new strategy for building next-generation artificial neural networks and neuromorphic processors for machine intelligence." Gordon McKay, Professor of Applied Physics and Electrical Engineering.
Electronic chips use the same manufacturing techniques as computer microprocessors.
False-color SEM image of neurons cultured above an electrode array. The actual neurons were much denser, with three to six layers of cells covering the entire electrode array.
The researchers developed the electronic chips using the same technology as computer microprocessors. The chip features a dense array of nanoscale vertical electrodes on its surface, which are controlled by a high-precision integrated circuit at the bottom. Each nanoelectrode is coated with platinum powder and has a rough surface, improving its ability to transmit signals. The neurons are grown directly on the chip, and an integrated circuit sends an electric current to each coupled neuron via nanoelectrodes, opening holes in the membrane to form intracellular channels. At the same time, the integrated circuit also amplifies the neuronal voltage signal received by the nanoelectrode through the small hole. "In this way, we combine the high sensitivity of intracellular recording with the parallelism of modern electronic chips." Lead author Jeffrey Abbott.
In experiments, the array recorded more than 1,700 rat neurons. Just 20 minutes of recording allowed the researchers to gain an unprecedented view of neural networks and successfully map more than 300 synaptic connections.
"We have also measured the effects of drugs on synaptic connections in rat neural networks with this high-throughput, high-precision chip, and now we are developing a wafer-scale system for high-throughput drug screening in neurological disorders such as schizophrenia, Parkinson's disease, autism, Alzheimer's disease and addiction." "Abbott said.