Mini Matrix Main Amplifier System

The TREC Main amplifier (MAF-05) is a 5-channel, differential main filter/amplifier for neurophysiological applications (e.g. extracellular recording with microelectrodes).

Key features of the MAF: SUA-Filter Version:

  • 5 amplifier channels
  • Low-noise amplifier technique
  • Differential input amplifier
  • Individual gain settings from x50 up to x5000 (in different steps)
  • Bandwidth 500Hz...20kHz (in different steps)
  • AC coupled input circuit
  • Low noise technique
  • Two level window discriminator for each channel
  • Impedance Test Unit
  • Microstimulation/lesioning
  • Audio Monitor with integrated loudspeaker

Key features of the MAF: Spike & LFP-Filter Version :

  • 5 amplifier channels
  • Low-noise amplifier technique
  • Differential input amplifier
  • Individual gain settings from x50 up to x5000 (in different steps)
  • Spike Bandwidth 500Hz...20kHz (in different steps)
  • LFP Bandwidth 0.1Hz...140Hz (in different steps)
  • AC coupled input circuit
  • Low noise technique
  • Impedance Test Unit
  • Microstimulation/lesioning
  • Audio Monitor with integrated loudspeaker
Dimensions and Weight: Depth (mm): 330mm
Width (mm): 450mm
Height (mm): 270mm
Weight (kg): 15kg
Power Supply: Supply voltage (V): 115VAC or 230V AC
Power Consumption (W): 50VA
Environmental conditions: Operating temperature range: +10°C to +40°C
Transport temperature range: +10°C to +40°C
Humidity: 20% - 80% RH (non-condensing)
Input data: Max. Filter input voltage: ±6V
Single Unit Activity (SUA) Band pass Filter/Amplifier Gain: 50, 100, 250, 500, 1000, 2500, 5000
Input impedance: 1M?//30pF
Low Pass cut-off [kHz]: 2 / 5 / 10 / 20 kHz
High Pass cut off [Hz]: 0.5 /1 / 2 kHz
Filter Characteristic: Butterworth
Input connector: BNC
Output Connector: BNC
Max. Output voltage swing: ±10V

Features

This Instrument is designed to work with TREC multielectrode Microdrive systems type “Mini Matrix” in research and teaching applications. Extracellular neurophysiological recordings with high impedance microelectrodes can easily be done with the Mini Matrix from central nervous systems in different species.

Figure 1: 8 channel Single Unit Activity Filter/Amplifier (SUA-08)

The Instrument is not intended for clinical measurements using human subjects.

The 5 channels of the MAF-05 contain a high-gain, low-noise differential amplifier stage followed by low frequency and high-frequency filters. The amplifier has a differential single unit activity (SUA) band pass filter–amplifier.

Record Mode offers two levels of signal gain (x10, x100) in a first stage and 4 additional levels (x5, x10, x25 and x50) in a final amplifier stage (see Figure 2).

The amplifier has a band pass characteristic for single unit activity (SUA) 500Hz…20kHz. An audio monitor and an electrode impedance tester are integrated in the device.

Figure 2: Block diagram of one SUA-filter/amplifier section

The MAF has an integrated audio monitor with loudspeaker. This unit provides audio reproduction of electrophysiological signals. The unit combines an audio amplifier in a compact, rugged package. This is especially suited to monitoring neural firing and muscle contractions. The audio monitor input is internally connected to the SUA-Filter amplifier output.

Figure 3: MAF (45 channel) with the following modules: (1) power supply, (2) filter/amplifier and window discriminator modules, (3) Impedance test & mode selection modules, (4) audio monitor with integrated loudspeaker

The integrated electrode impedance test unit allows to measure the impedance of microelectrodes loaded to Thomas RECORDING Microdrive systems like for example the TREC Mini Matrix. Furthermore it is possible to connect a stimulus generator (optional available from Thomas RECORDING) for microstimulation or lesioning via the microelectrodes.   

Furthermore each MAF SUA-Filter channel is equipped with a two level window discriminator. The window discriminator is an instrument for the separation of single neural spike trains from a multiunit recording containing more than one neural element. The window discriminator of the SUA-Filter produces a window in amplitude. The window can be adjusted in height, above or below baseline. The trigger point is set by a continuously adjustable level control for either positive or negative slope detection. The signal and both window levels are multiplexed so that only one channel of the oscilloscope is necessary. A reliable description of the activity pattern of a single, well-isolated neuron is the key to many important experiments in neurophysiology. Once the quality of the recorded signal has been optimized and enhanced by the proper microelectrodes, amplification, and band pass filtering of the SUA-filter/amplifier module, the yield is determined by the power and flexibility of the spike discrimination and processing system. The TREC modular signal conditioners have been optimized for this purpose.

The MAF-Filter/Amplifier is modular system that is available with SUA-Filter/Amplifier modules (5 channel band pass filter 500Hz…20kHz and Window discriminator, see figure 4 and 5) or with Spike/LFP-Filter Amplifier modules (5 x spike band pass filter 500Hz…20kHz and 5 x Local Field Potential band pass filter 0.1Hz…140Hz, see figure 6 and 7). Both devices have integrated Impedance test and mode selection device offering three operation modes of the Mini Matrix preamplifier (Impedance Test, Recording and Microstimulation) and an Audio Monitor with integrated loudspeaker.

Figure 4: MAF-SUA-Filter/Amplifier with window discriminators (5 channel) integrated impedance test & mode selection module, audio monitor module and integrated loudspeaker

Figure 5: Complete 5 channel recording setup with MAF-Filter/Amplifier (SUA)

Figure 6: MAF-LFP-Filter/Amplifier with 5 spike and 5 local field potential filters (5 channel) integrated impedance test & mode selection module, audio monitor module and integrated loudspeaker

Figure 7: Complete 5 channel recording setup with MAF-Filter/Amplifier (Spike & LFP)