A new generation of miniature recording probes can track the same neurons inside tiny mouse brains over weeks—and even months.

The new tools build on the success of the original Neuropixels probes released in 2017 and currently used in more than 400 labs. Neuropixels 2.0 are much smaller—about a third the size of their predecessors. They’re designed to record the electrical activity from more individual neurons and have the unique ability to track this activity over extended time periods. That makes them especially useful for studying long-term phenomena like learning and memory in small animals such as mice, says Tim Harris, a senior fellow at HHMI’s Janelia Research Campus who led the project. Harris and his colleagues describe the advance in a paper published online April 15 in the journal Science.

Neuropixels 2.0’s advances come from several key innovations, Harris says. Janelia scientists and engineers developed new ways to process the data. Strategic changes to the layout of the probes helped make them better suited to certain tasks. And engineers at imec, the non-profit nanoelectronics center that manufactures the probes, used imec’s proprietary technology to design, develop, and fabricate the probe.