Electrode Site Span (Width)
Hardware
Electrode site span (width) is the distance between the outermost electrode sites across a probe or grid, perpendicular to the shank; it sets how wide a region one insertion or placement samples.
It is the lateral partner of site span, which runs along the shank. On a single-shank linear design the width is a few tens of micrometres — the width of one site column — and on a multi-shank design it is the shank separation times one less than the shank count: 600 µm for four shanks at 200 µm.
Width is the number to match against a structure's lateral extent. A 600 µm width spans a few cortical columns in one plane; a Matrix 3D array reaches 1.5 mm and more; a surface grid's width is its whole footprint, up to tens of millimetres on a large-animal ECoG array. With the depth span it defines the site footprint, the rectangle of tissue a design covers, from which site density is computed.
Typical values
| Catalog silicon probes | 0 to 3.5 mm; about 0.6 mm is the median |
|---|---|
| Four shanks at 200 µm separation | 600 µm |
| Design-space parameter | Span (width) (spanXUm) |