Optical Stimulation
Optoelectrodes for optogenetics — light delivered on the same trajectory as the recording sites, so the neurons you record are the neurons you stimulate.
An optoelectrode is a silicon probe whose package carries an optical fiber, fitted at assembly so light leaves the fiber beside the recording sites. That placement is what supports a causal claim: the units you record are the units you illuminate — a claim a separately implanted fiber and probe cannot make. It is a package build, not a separate probe, so any probe design offered in an optoelectrode package can be ordered this way.
Three decisions make an optogenetics setup
Choose the probe design for the target first, then the optoelectrode package the preparation needs, then the light path that drives it. Each card below opens the webstore filtered to that part; the configured set opens all three together.
Which experiments an optoelectrode is for
Choose an optoelectrode when the claim is causal and the light and the recording must share a place.
Optogenetic tagging
Identify a recorded unit as part of a genetically defined population by its short-latency response to light — which needs the light and the site within a detection radius of each other.
Closed-loop stimulation
A recorded event triggers light at the recorded place, on the same array.
Circuit dissection
Silence or drive a population and read the effect on its neighbors on the same shank.
When not to
A wide-field manipulation read from a distant structure. There the fiber adds cross-section along the whole trajectory and an artifact at every pulse, and a separate fiber costs nothing.
Optoelectrode builds by package
The fiber is added to a package family you already know; the probe, connector and cable are whatever that family specifies.
A-Series — acute and intra-operative
16 to 128 channels on a rigid printed-circuit interconnect ending in a standard connector; most often mice and small animals.
CM — chronic, cableless
16 and 32 channels with the connector mounted on the assembly — no interconnect to route or anchor. The 16-channel build weighs 0.25 g.
Hybrid — chronic, floating
16 to 64 channels on a flexible polyimide cable, so the probe moves with the tissue rather than being held rigid against it.
ZIF — chronic, zero insertion force
16 and 32 channels mating with TDT Zif-Clip headstages, sparing the shank at every headstage change.
Q-Trode — one tetrode
Four channels on a CQ4 connector, so the tagged cells are the separable ones.
Vector — deep targets in large animals
16 and 32 channels bringing light and recording down a 70 or 110 mm trajectory.
Drug delivery — light and fluidics
16 channels with a fluidic channel alongside the fiber, to deliver or sample an agent where you stimulate.
Activus SiNAPS — active pixel
256 and 1,024 channels with no headstage in the recording chain; records only, stimulation is optical.
MRI-conditional builds
CM optoelectrodes built without ferromagnetic parts for use in or near an MR scanner, on the MRI Omnetics connector.
The light path
Optical stimulation runs from a separate light source. The fiber on the package terminates in a standard fiber-optic connector; the parts between it and the source are chosen for the preparation.
Laser and LED sources
Single- and dual-wavelength sources, including a dual 473/594 nm laser package and LED sources, with a pulser for timed stimulation.
oDrive for chronic work
The optogenetics version of the dDrive chronic microdrive: four drive ranges from 2.5 to 10 mm, 250 µm per turn on a 6.2 × 9.75 mm footprint, 0.55 to 0.95 g, carrying one optical fiber in a 1.25 mm ferrule.
Freely moving animals
An optical rotary joint keeps the fiber from twisting as the animal turns; patch cords, ferrules and sleeves carry the light the rest of the way.
Filters and fiber stock
Optical filters, raw and ferrule fiber, and couplings for building or repairing a light path.
Before the first session
Light and tissue are the variables, not the probe. Irradiance falls steeply with distance from the fiber tip, so which neurons are illuminated is set by the fiber position and tissue scattering, not by the source power alone.
Map the gradient across your array
Sites near the fiber see a different stimulus from sites far from it. That gradient is part of every result; map it before you interpret one.
Measure the photoelectric artifact
Light striking an electrode produces an artifact at pulse onset that scales with irradiance. Record it in saline and in a non-expressing control at the irradiance you will use, then design the pulse so the artifact is separable in time from the response.
Confirm the fiber on the quotation
Core, cladding, numerical aperture and length are not in the product records. The fiber is integrated on the shank rather than placed at surgery, so settle it with an application scientist before ordering.
Further reading
Optical Stimulation — FAQ
Ordering and using optoelectrodes.
What is an optoelectrode?
A silicon probe whose package carries an optical fiber fitted at assembly, so light is delivered on the same trajectory as the recording sites and the neurons recorded are the neurons illuminated.
Is an optoelectrode a different probe?
No. It is a package build: the probe design is unchanged, and the optoelectrode form is chosen as the package option when the probe is ordered.
Which probe designs can be ordered as optoelectrodes?
Those offered in at least one optoelectrode package — across the A-Series (including its polytrode, tetrode, Buzsaki and Isomura layouts), Q-Trode, Vector, drug-delivery and SiNAPS lines. The probe collection on this page lists them.
Which light source do I need?
Any laser or LED source with a compatible fiber-optic connection; the package fiber terminates in a standard connector. Match the wavelength to the opsin you express.
What fiber does the package use?
The fiber configuration is confirmed on the quotation. Core, cladding, numerical aperture and length are not listed in the product records, so an application scientist settles them with you before ordering.
Can I use an optoelectrode in a freely moving animal?
Yes. Use a chronic build (CM, Hybrid or ZIF), the oDrive where depth adjustment is needed, and an optical rotary joint so the fiber does not twist.
Configure your optogenetics setup
Send the probe design and preparation; an Application Scientist will confirm the package, fiber and light path, and quote the set.