Biography

Tim Harris is a Research Professor at Johns Hopkins University Department of Biomedical Engineering. He has recently completed an 18 year appointment as Group Leader and Senior Fellow at the HHMI Janelia Farm Research Campus in Ashburn, VA. In the past he spent 18 years at Bell Labs central research, 12 years as research director at 3 different biotech startups. In 2008 Tim moved to the HHMI Janelia Research Campus.  Among other projects he initiated a Neuropixels, jointly funded by HHMI, The Allen Institute for Brain Research, Gatsby Charitable Foundation, and the Wellcome Trust, partnered with Cambridge University and University College London.  The resulting probes 384 channel fully integrated probes have been available since 2017. More than 28,000 probes have been shipped to more than 1,600 labs since January, 2018. At Johns Hopkins, with funding from the NIH BRAIN Initiative, the Harris lab is finalizing the family of recording probes with Neuropixels NXT, small enough for more than 6,000 channels in a freely moving mouse. Future work seeks to simplify the practice of multiprobe implants and add high spatial and time resolution closed loop programable electrical stimulation devices to the matrix of recording probes.

Talk Title: Neuropixels: History, Status, and Future

Neuropixels are devices for recording neural signals in the brains of experimental animals, usually rodents, but also in some cases primates. They’re small micromachine silicon devices that are tens of micrometers wide, 20µm thick and 10mm long. They’re inserted into the brain and they’re covered with sensors to measure the electrical signals generated by neurons. There are similar devices that have been used in the past but the fabrication technology didn’t allow you to have more than 12 or 16 sensors on a stick that you used to put into the brain. So, you had to choose between spreading your sensors out and having a lot of empty space or putting them close together so you couldn’t measure very much tissue simultaneously and there was a positioning problem; you had the move the probe around to get it where you wanted it.

Over the past decade, the capacity of electrophysiology has risen 5-10X driven in large part by the introduction of Neuropixels 1.0 in 2017. The addition of the smaller 384 channel Neuropixels 2.0 probe in 2023 enables facile chronic use, 2 probes with the head stage weighs less than 1.3 grams. The pending introduction of the 1536 channel probe Neuropixels 2.0 QuadBase in Q2 2024 followed by the Neuropixels 2.0 size 1536 channels Neuropixels NXT Probe will add to the more than 1200 labs using Neuropixels.