Brain Coverage Density
Hardware
Brain coverage density is the number of electrode sites per cubic millimetre of the neural interface volume — the three-dimensional form of site density, and the fairer way to compare a multi-shank design against a single-shank one.
It is site count divided by neural interface volume.
The two-dimensional site density is computed over a footprint, and a single-shank design's footprint is almost a line, so its density reads high however far apart its sites are. Dividing by volume instead asks how densely the design samples the block of tissue it actually occupies, which is the question a reader comparing a 4-shank, a 16-shank and a Matrix 3D design is asking. A high value means a small block sampled finely, for unit isolation within one structure; a low value means a large block sampled sparsely, for mapping across structures. It has no field in a probe name and is published in the design space from the site positions.
Typical values
| Catalog silicon probes | about 7 to 11,000 sites/mm³; about 1,000 is the median |
|---|---|
| Definition | site count ÷ neural interface volume |
| Design-space parameter | Brain coverage density (brainDensityPerMm3) |