Probes

Precautions

Warning

Probes are very delicate. When handling any probe, only touch the PCB board.

New users sometime break probes due to lack of handling/insertion experience. To gain experience without risking the most valuable probes, consider training first with low-quality probes (available upon request).

Performance Specifications

For a detailed explanation of the fabrication steps, physical dimensions, and electrical performance of our probes, see:

Scholvin, J., Kinney, J.P., Bernstein, J.G., Moore-Kochlacs, C., Kopell, N., Fonstad, C.G. and Boyden, E.S., 2016. Close-packed silicon microelectrodes for scalable spatially oversampled neural recording. IEEE Transactions on Biomedical Engineering, 63(1), pp.120-130.

Cleaning and Care

Adapted from NeuroNexus:

1. Store probes in their shipping box.
2. After withdrawal from tissue after an experiment, immediately rinse with a gentle stream of distilled water. Soak the probe (only the silicon shank; avoid soaking the epoxy or PCB) in a protein-dissolving detergent or enzyme such as contact lens solution or diluted surgical instrument detergent. This process may take a few hours.
3. After in vivo use, isopropyl alcohol (e.g. 70% IPA) can be used for cleaning AFTER the protein dissolving procedure (See Step 2).

Warning

Without first dissolving the residual tissue from the probe, alcohol could cause protein to stick to the electrode sites.

4. DO NOT use ultrasonic cleaners as this may cause damage.
5. DO NOT autoclave probes as this may cause damage.

Impedance Testing

The signal quality of each channel is determined in part by its impedance. To measure the impedance of individual channels in a probe, see Impedance Testing.

Rejuvination

With regular practice a neurosurgeon can reach a level of proficiency in handling and usage of probes so as to not break them and instead allow repeat experiments with a single probe. In this case, to preserve the low impedance of the individual recording sites and thereby the signal-to-noise ratio and quality of the data, it is important to follow the cleaning and care instructions described in Cleaning and Care.

Nevertheless, even with proper care, single-site impedance rises with repeated usage. It is unclear to us whether impedance is rising do to fouling (accumulation of foreign material on the sites), or loss or structural rearrangement of the plating material. Regardless, deep cleaning and re-electroplating may be necessary to lower impedance and re-establish excellent signal quality.

Channel maps

The geometrical arrangement on each probe of all channels is captured in a collection of Channel Maps.