Chronic Recording
A chronic recording is a preparation with a permanently implanted probe, so the same brain region, and often the same neurons, are recorded across days, weeks or months in an awake, behaving animal.
What the preparation gives: recording during learned behavior, longitudinal tracking of units, and many sessions per animal. What it costs: a surgery that anchors the implant to the skull, a tissue response that can reduce signal amplitude over weeks, and the mass and volume of the implant, which the animal wears for the study; a 30 g mouse tolerates far less on its head than a rat. Signal quality is usually highest in the first week; some implants remain stable for months with good surgical technique and materials, and a microdrive recovers units after the tissue settles.
The chronic packages are CM for a mouse, X-Series where mass is the limit and the chain is X-Series, Hybrid for a floating implant or a microdrive, and the Vector chronic builds for a deep target in a large animal. For a freely moving animal an X-Series headstage at 0.9 to 1.5 g streams to XDAQ over one cable, through a commutator where the animal turns, and the implant's mass budget is package, headstage and drive together. The surgical steps are in the chronic surgical guide; the alternative is an acute recording.
Typical values
| Duration | days to months |
|---|---|
| Subject | awake, behaving |
| Packages | CM, X-Series, Hybrid, Vector chronic |
| Headstage, freely moving | X-Series, 0.9 to 1.5 g, one cable to XDAQ |