Polytrode Layout
Two or more dense columns of sites — Poly2, Poly3 and denser — combining a linear array's span with a tetrode's overlapping view.
Poly2 is two columns of sites; Poly3 is three. The layout mixes the benefits of the other two: sites are close enough that one neuron is represented on several at once, as in a tetrode, while the columns still run the length of the shank and sample a larger space than a discrete cluster.
Read the number as the column count. The catalog documents two variations; the corpus carries four, and all four are orderable:
| variant | columns | catalog designs |
|---|---|---|
| Poly2 | 2 | 21 |
| Poly3 | 3 | 12 |
| Poly4 | 4 | 1 |
| Poly5 | 5 | 4 |
Poly2 and Poly3 are the common cases and are what the catalog illustrates. Poly4 and Poly5 are narrow but real — five catalog designs between them, on the densest shanks in the A-Series. More columns across a fixed shank width means more sites seeing the same neuron, which is what a sorter separates on; it also means more channels spent per millimetre of trajectory.
In a model number the layout field reads poly2, poly3 and so on.