A-Series Isomura Probes
A-Series layout with parallel shanks at a pitch fixed during fabrication, built to sample the same layer across several cortical columns in one penetration.
What the layout does
Isomura designs place parallel shanks a set distance apart so that the same anatomical layer is recorded simultaneously at several lateral positions. The experiment it supports is comparison across columns rather than resolution within one.
The pitch is a selection criterion, not a setting
Shank pitch is fixed at fabrication. A pitch chosen for rat cortex puts two shanks in two columns in a mouse — a different experiment, not a smaller one. Check the pitch against the structure before choosing anything else about the layout; no other parameter can compensate for it afterwards.
Specifications
Designs run to four parallel shanks, 16 to 674 sites. Sites are larger than elsewhere in the A-Series at 172 to 305 µm², which lowers impedance; the array is built to compare a layer across columns rather than to resolve single units within one.
Substrate
Silicon, 15 µm as standard, with a 50 µm option on some designs.