Multichannel Systems MEA-System Manual - Manual (Page 15)

Appendix
15
3.4.1 Microelectrode Arrays (MEAs)
The recording field of a standard MEA with 60 electrodes is a square grid of 8 x 8 electrodes
with a total length between 120 μm to 5 mm in the middle of a circular, which is about 2 cm
wide. 256MEAs for USB-MEA256-Systems have 256 electrodes in a 16 x 16 electrode grid,
120MEAs for MEA2100-120-Systems have 120 electrodes in a 12 x 12 grid, perforated MEA32S12-
Lx for MEA2100-32-System have 32 recording and 12 stimulation electrodes. It is possible to glue
a culture chamber onto the MEA, made of plastic (Macrolon) or of glass.
The layout of the MEA electrodes follows the scheme of a standard grid: The first digit is the
column number, and the second digit is the row number. For example, electrode 23 is positioned
in the third row of the second column. The numbering follows the standard order from left
to right, and from top to bottom. This numbering is used in the documentation of the MEAs,
the MEA amplifiers, MEA2100 headstages, and in the data acquisition programs MC_Rack, LTP-
Director, and Cardio2D. That means, if you want to record data from electrode 23, you choose
channel 23 for setting up the channel layout map. Please make sure that the appropriate 2-
dimensional data source setup ”2 dim. (MEA)” or “Configuration” selected in the data source
settings of MC_Rack. For more details, please refer to the MC_Rack help or manual.
Microelectrode arrays are available in various configurations:
 Different electrode layout grids (8x8, 6x10, High Dense 2x(5x6), 4 Quadrants, Hexa, 6wellMEAs);
 Different electrode diameters and spatial resolutions;
 Different electrode materials (Titanium nitride, gold or PEDOT);
 Opaque (titanium) or transparent (indium tin oxide) tracks and contact pads.
For more information on MEA types, electrode layouts, MEA handling, coating and cleaning,
please refer to the MEA manual.
3.4.2 Signal Amplification and Filters
The standard MEA amplifier combines the probe interface with a band pass filter and the signal
amplification in one instrument.
The MEA1060-BC amplifier with blanking circuit is a 60-channel preamplifier with a broad
bandwidth. Filter specifications and gain are defined by the following filter amplifier.
Different filter settings are used to enhance the signal-to-noise ratio. The pass band of the filter
amplifier depends on the signal type. It is generally useful to filter the data with a cutoff at the
highest signal frequency.
For slow signals like field potentials, a bandwidth of 1 to 300 Hz is appropriate. If you like to
record fast signals like spikes, a pass band of 300 Hz to 3 kHz is suitable. Cardiac signals have
fast and slow components; therefore, you usually need a wider bandwidth of 1 Hz to 3 kHz.
Multi Channel Systems MCS GmbH provides custom amplifiers with a bandwidth of your choice,
from 0.1 Hz to 10 kHz. Please note that it is often wise to acquire the data with a broadband
amplifier and use the digital filter of the MC_Rack program to change the pass band and filter
the raw data. This way, you are much more flexible in designing your experiments. As a further
advantage, you can see the original (not filtered) data as well. This is especially important because
all filters are known to distort signals. On the other hand, you may need a higher sampling rate to
avoid aliasing, and the signal-to-noise ratio is lower. See also the chapter "Data Acquisition" for
more information.