System Eckhorn Microdrive
7-Channel Single Electrode System
The multielectrode manipulator "System Eckhorn" was developed in the laboratory of Prof. Dr. R. Eckhorn at the Department of Neurophysics, Philipps-University Marburg, Germany and successfully used for parallel independent insertion of fiber microelectrodes through the intact dura into the brain of chronically prepared cats and monkeys (see "downloads & publications": ,).
The 7 electrode Eckhorn microdrive allows to drive up to seven fiber microelectrodes (diameter=80µm) independently from each other to different depths of the brain. The max. electrode travel distance of each fiber microelectrode is up to 35mm (electrode travel extensions are possible and available on request!). A 7 channel low noise preamplifier is integrated in the microdrive metal chassis. The microelectrodes are completely shielded by the microdrive chassis (working like a Faraday cage) so that electrical interference from the laboratory environment does not cause noise problems. Due to the rubber tube driving principle of the Eckhorn Matrix it is possible to record neural signals while the electrodes are moving in brain tissue!
- Axial resolution better than 1μm, x-y-Positioning with a grid and special holder
- Patented rubber-tube drive, no hysteresis, slick or free motion due to patented rubber tube drive (avoids drawbacks of cable, direct or hydraulic driven systems)
- Electrode travel range up to 35.000μm
- Variable speed range from 0...250μm/s, higher velocity on request
- 7- and 16- channel Version available
- 28 or 64 channel Tetrode Versions available
- 49 or 112 channel Heptode Versions available
- No electrode connection cables free in air! Complete metal shield around all microelectrodes
- Suitable for cortical and deep brain recordings
- Very close electrode spacing available (down to 80μm)
- Different electrode arrangements available (linear, concentric, etc.)
- Integrated low noise preamplifiers
Microdrive Technical Data
|Number of motors:||7|
|Electrode travel distance per channel:||up to 35.000µm|
|Resolution per step:||1µm|
|Max. electrode speed:||up to 250µm/s|
|Electrode driving principle:||patented Thomas rubber tube drive|
|Motor control:||via included software and microprocessor motor control unit|
Pre-Amplifier Technical Data
|Number of channels:||7|
|Gain per channels:||x19|
|Pre-Amplifier input:||AC coupled|
|Preamplifier supply voltage:||+/-6V DC|
|Operation modes on each channel:||Recording, Stimulation/Lesion, Impedance Ttest|
|Stimulation modes:||optical, electrical|
|Size:||158mm x 70mm x 100mm|
With this fiber-electrode manipulator a broad range of even very thin shafted probes can be handled, including fiber and wire-electrodes with shaft diameters down to about 25 µm. The patented driving principle of the Eckhorn Manipulator offers an outstanding electrode positioning accuracy. Compared with hydraulic, direct motor driven or cable controlled microdrives, the patented fiber electrode manipulator "System Eckhorn" does not cause hysteresis errors of the electrode movement. Hysteresis error is generally a result of stiction and free motion of the driving mechanism. Our system has a higher degree of positioning accuracy due to its rubber tube driving mechanism being almost absolutely free of stiction and free motion.
Using Thomas Eckhorn Matrix systems with patented rubber tube drive allows to record neural activity while the electrode is moving in the brain. So it is very easy to search active neurons in the brain.
The Thomas Eckhorn Matrix systems have some advantages in comparison to other multielectrode microdrive systems for neurophysiological research presently available on the market:
- Vibration-free positioning of up to 16 quartz-platinum/tungsten microelectrodes in 1µm steps
- Patented rubber tube driving principle
- High positioning accuracy, due to lack of stiction and free motion
- Easy exchange and calibration of microelectrodes within minutes
- Advances up to 16 microelectrodes/tetrodes independently in 1µm steps up to 35.000µm (other electrode travel distances on request!)
- Xyz-manipulator travel-distance: z=0-30mm, x= ±10mm, y=±10mm
- Continuous low noise recording while the electrode scans the tissue at low velocity,
- No noise introduction in the recordings so that you can search active neurons in the brain
- No electrode connection cables free in air, no electrical noise pickup from environment (e.g. motors, radio stations)! Competitor drives pickup electrical interference from the environment so that you for example can hear radio station music or electrical artifacts from lab devices from the audio monitor loudspeaker instead of neural spikes!
- Electrode moving velocity adjustable (1-250µm/s), moving direction selectable
- Low noise 7 or 16 channel preamplifier is integrated into the microdrive chassis, system is completely shielded to avoid electrical noise pickup from the environment, three preamplifier operation modes: record, electrode impedance test, electrical stimulation/lesioning
- System is completely delivered with motor control device, integrated preamplifier, software, xyz-manipulator, chamber holder, exchangeable head, handheld remote control, etc.
- Exchangeable manipulator head allows manifold electrode configurations and interelectrode spacings
- Electrode spacings from 80µm up to some millimeters possible due to exchangeable Eckhorn Matrix heads
- The system is modular and adaptable to the end user´s requirements.
- The Eckhorn Matrix is usable for cortical as well as deep brain recordings in all kinds of research applications
- User friendly computer controlled system with LAN (local area network) communication via TCP/IP protocol between motor control unit and personal computer. Software package is part of the system.
- Using very thin shaft Thomas microelectrodes (outer diameter 80µm) causes minimal tissue damage.
- Different neurophysiological methods are available for the Eckhorn Matrix systems (e.g. optogenetics, microinjection)
Figure 4: Neural data recorded in a primate amygdala by using a 7 electrode Eckhorn Matrix (data kindly provided by Prof. Dr. Katalin Gothard, Arizona Health Science Center, Tucson, USA)
The Eckhorn Matrix system is available for small animal stereotaxic instruments (see figure 10) as well as for primate experiments (see figure 11).
Thomas RECORDING offers a broad range of exchangeable Microdrive heads with different guide tube arrangements and electrode spacings for the 7- and 16-Electrode Eckhorn Systems.
There is a broad range of different Microdrive heads available. We also can offer customized solutions!
Electrical Stimulation / Impedance Test with the Eckhorn Matrix
The Eckhorn Matrix preamplifier is integrated in the microdrive chassis and has three operation modes: Recording / Electrode Impedance Test /Stimulation or Lesioning. The standard operation mode of the preamplifier is “Recording”. To use the other two modes Thomas RECORDING offers a special designed device that is called Mode Selection & Impedance Test Device (MSD).
The MSD is optional available, for more information please see the productpage of MSD.
Thomas RECORDING offers a broad range of solutions for mounting the Eckhorn multielectrode systems to stereotaxic instruments. Below you can find some examples for Eckhorn microdrives mounted to small (see fig. 10) and large animal stereotaxic instruments (see figure 11). It is our strength to adapt our Microdrive to stereotaxic setups. Please feel free to ask for your individual adaptation.
For making drug injection experiments with the Thomas Eckhorn Matrix system we offer a special designed high pressure microinjection system. One of the 7- or 16-single microelectrodes of the Eckhorn Matrix can be replaced by a microinjection cannula. The microinjection cannula (OD=120µm) has a tapered tip and is equipped with the patented Thomas rubber tube drive so that you can position the microinjection cannula tip together with the recording microelectrodes with high positioning accuracy (better than 1µm). The microinjection system consists of a special designed and computer controlled syringe pump that is connected to the microinjection cannula via a special thick wall tubing.
The precision micro motor of the microinjection pump is controlled by the same motor control unit and graphical user interface as the Thomas Eckhorn Matrix. This guarantees a high precision and convenient experimental control of the injection/recording experiment.
Thomas RECORDING offers a complete range of Eckhorn Matrix accessories for optogenetic experiments. One of the 7- or 16 single microelectrodes or tetrodes is replaced by an optical fiber (OD=120µm). The optical fiber has a tapered tip and is equipped with the patented Thomas rubber tube drive so that you can position the optical fiber tip together with the recording microelectrodes with high positioning accuracy (better than 1µm). Figure 13 shows an Eckhorn Matrix head with concentric guide tube arrangement and a single optical fiber in the center position. The recording microelectrodes are concentrically arranged around the optical fiber in the center of this arrangement.
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