ECoG Series Thin-Film Grids
Thin-film polyimide arrays that record from the cortical surface, placed epidurally on intact dura or subdurally on the pia, where conformality rather than fixation is what keeps the sites in contact.
What holds the array against the brain
Nothing anchors a surface array but its own fit. The cortex is curved, and it moves with respiration and pulsation, so contact is maintained by the substrate following that surface rather than by any fixation. The 12 µm polyimide film is thin enough to do that; a stiffer substrate would bridge the curvature and lift sites off the tissue.
Epidural or subdural — the decision that shapes the experiment
Epidural, on intact dura: lower risk of cortical injury, better behaved chronically, and the dura attenuates and spatially blurs what reaches the sites.
Subdural, on the pia: higher amplitude and finer spatial resolution, at the cost of opening the dura — a larger acute insult and a harder chronic preparation.
Neither is the better choice in general. Decide it from how long the preparation has to survive and how fine a spatial claim the result has to support.
Specifications
12 µm polyimide, platinum sites of 177 µm², 4 to 256 sites depending on design, cable lengths from 5 to 100 mm. Packages run from H16 through H256, IH256, AVH256 and AVIH256.
Surface and depth together
An ECoG array pairs with a penetrating probe in the same preparation, giving a surface map and a laminar profile from one animal. The surface array goes on first.
Research use only.