Why not record from every electrode with a CMOS scanning probe?

Abstract

Neural recording devices normally require one output connection for each electrode. This constrains the number of electrodes that can be accommodated by the thin shafts of implantable probes. Sharing a single output connection between multiple electrodes relaxes this constraint and permits designs of ultra-high density neural probes.Here we report the design and in vivo validation of such a device, a complementary metal-oxidesemiconductor (CMOS) scanning probe with 1344 electrodes and 12 reference electrodes along an 8.1 mm x 100 μm x 50 μm shaft; the outcome of the European research project NeuroSeeker. This technology presented new challenges for data management and visualization, and we also report new methods addressing these challenges developed within NeuroSeeker.Scanning CMOS technology allows the fabrication of much smaller, denser electrode arrays. To help design electrode configurations for future probes, several recordings from many different brain regions were made with an ultra-dense passive probe fabricated using CMOS process. All datasets are available online.

Recording from the same neuron with high-density CMOS probes and patch-clamp: a ground-truth dataset and an experiment in collaboration

“…23; see Materials and Methods). Our overall aim was to generate and share a ground-truth dataset for Neuropixels, which are part of a new generation of extracellular probes with high channel count and density 10,11 .…”

“…We were thus able to provide an estimate of within-unit variability for a few commonly-used spike features. Finally, we highlight the richness of spatiotemporal signatures present in extracellular recordings, which is emphasized in high-density probes 10,11 .…”

“…These datasets have been acquired for tetrodes/single-wire electrodes [18][19][20][21] or in slice preparations 22 , where background activity is greatly reduced. We recently added to this literature by publishing and sharing a ground-truth dataset from silicon polytrodes 23 , but these devices have significantly different channel count and arrangement from the new CMOS probes 10,11 . Ground truth datasets from tetrodes in the hippocampus 18 and polytrodes in cortex 23 have proved invaluable for constraining, benchmarking and improving spike sorting algorithms 15,[24][25][26][27] .…”

“…Understanding how the brain works requires seeing the forest and the trees: we must track large populations of neurons, but also resolve their activity as units 5,6 . As a method, extracellular recordings have come a long way towards achieving this goal, progressing through technological advances from recording single neurons in the 1950s [7][8][9] to several hundreds in the 2010s [10][11][12] .…”

Massively Parallel Microwire Arrays Integrated with CMOS chips for Neural Recording

“…A number of innovations have been made for electrical recording using flexible materials on the surface of the brain, and planar probes have seen rapid development based on silicon processing techniques [15][16][17] . However, recording from volumetrically distributed sites at scale has remained challenging due to the inherently two-dimensional nature of these devices.…”