Brain Coverage Density
Hardware
Brain coverage density is the number of electrode sites per cubic millimeter of the neural interface volume — the three-dimensional form of site density, and a fairer basis for comparing 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 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) |