These super-thin probes can map hundreds of neurons in real time

In a bid to further understand brain activity in detail, an international team of researchers has developed super-slim silicon probes which can map the activity of multiple neurons in real-time.

The probes, dubbed Neuropixels, are 10mm (0.39 inches) in length and just 20 micrometres thick (0.00078 inches), which is thinner than a single strand of human hair. They carry as many as 960 super-sensitive recording points and map the activity of not one or two but hundreds of neurons in different parts of the brain.

This provides scientists an opportunity to understand how neurons coordinate between themselves to process information. It could not only help them study how different brain activities relate to different decisions and behaviour, but also provide new insights into how disorders like depression or Alzheimer's affect the brain's normal functioning, ultimately leading to new ways to treat these diseases.

"To understand the brain, we need to understand how a lot of neurons spread all over the brain work together," said University College London's Matteo Carandini, who is a member of the team that developed these probes.

"Until recently, it was possible to measure the activity of individual neurons within a specific spot in the brain or to reveal larger, regional patterns of activity – but not to do both at the same time." The conventional method involved using wire electrodes which had no more than a few dozen recording sensors.

However, Neuropixels have enabled scientists to record from more neurons simultaneously than it was ever possible. While recording, the new super-tiny probes automatically transform electric signals into digital data for computational analysis.

As of now, some 400 prototypes of the probes are in the testing phase, with researchers from different parts of the world using them for various studies. The tiny device would be made available to neuroscientists at cost price next year. However, the price range for these devices has not been revealed yet.

The experiments have been conducted only on mice and rats, but it is important to note that their brains are known to be good models for the human brain, with smaller but very similar structures and connectivity patterns.

In the study published by the journal Nature, researchers detailed how these probes were used to monitor the activity of some 700 well-isolated neurons in the five brain structures of a mouse. They even used the probes to demonstrate it could be used on freely-moving animals for long-term experiments.

"Neuropixel probes will change what we know and even how we think about the brain," said Andrew Welchman of UK's Wellcome Trust, another member of the research team. "We still have a long way to go in uncovering the brain's mysteries, but this new technology is an important development."