Site Pitch (Across)
Hardware
Site pitch (across) is the centre-to-centre spacing between columns of electrode sites across the width of a shank or over the face of a grid, in micrometres; it sets the lateral resolution of the design, as site pitch along the shank sets its depth resolution.
On a linear layout there is one column and no across pitch. On a polytrode layout it is the column spacing inside the shank — 17 to 43 µm on the catalog's Poly2 and Poly3 designs, so that one neuron appears on sites in more than one column and a spike sorter can place it laterally as well as in depth. On a multi-shank design the across pitch between shanks is the shank separation.
On a thin-film grid the two pitches describe the surface map. A 300 µm pitch in both directions on a micro-ECoG grid resolves cortical columns; a millimetre pitch on a rodent EEG array places one site over each region of interest. The along-shank number is under site pitch; the layouts that set both are under probe geometry.
Typical values
| Polytrode column spacing, catalog | about 17 to 43 µm |
|---|---|
| Across shanks | equals shank separation, 125 to 500 µm |
| Design-space parameter | Site pitch (across shanks) (sitePitchXUm) |