EEG Series Thin-Film Grids
Hardware
An EEG array records from the outer surface of the skull, with no bone removed, no dura opened and no cortex exposed; skull and scalp spread the signal, so it measures rhythms and state rather than local circuit activity, in a preparation that is held for months.
The difficulty moves to alignment and fixation. Designs are dimensioned from bregma, so placement decides what is sampled: a layout drawn for mouse cortex placed on a rat skull samples different structures. A drop of water adheres the array while the fixation cures. Catalog designs for mouse and rat have 6 to 32 platinum disc sites of 500 µm on 12 µm polyimide, with cables of 7, 8, 10 and 50 mm. Applications are sleep and wake staging (vigilance state), seizure detection, cortical rhythms and long-duration monitoring; the four grid families and their packaging are under thin-film grid, the reference decision in the EEG referencing guide, and the surgical steps in the EEG surgical guide.
Records and stimulates. Research use only.
Typical values
| Catalog designs | 9 |
|---|---|
| Sites | 6 to 32 |
| Site diameter | 500 µm |
| Substrate | 12 µm polyimide; platinum sites |
| Placement | skull surface, referenced to bregma |