Alpha MED Scientific MED-A64MD1A, Product Manual

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8
Amplification Settings
Acquisition-Bandwidth Settings
The MED64 Main Amplifier (64-CHANNEL MAIN AMPLIFIER) has a broad bandwidth range between 0.1Hz-10kHz
which allows users to record several types of extracellular potentials. The amplifier has analog low-cut filter
settings (high- pass filter) available at 0.1, 1, 10, and 100 Hz cutoffs and high cut filter settings (low-pass filter)
available at 1, 2.5, 5, 7.5, and 10 kHz cutoffs, which can be selected in the Mobius software. Signals with
frequencies higher than the value set for low-cut filter and lower than the value set for high-cut filter are
acquired.
Keep in mind that filtering distorts the signal. Thus, it is usually better to record the signal at a wide bandwidth
and analyze the acquired signals using Mobius’s digital filter if necessary. The noise level for the MED64 System
is very low due to its low-impedance electrodes. Usually a good signal-to-noise ratio can be achieved even with
the high-cut filter (low-pass filter) of 10kHz. On the other hand, Setting the low cut filter (high-pass filter) with
0.1 Hz is usually unnecessary except for recording of very slow signals such as from gastrointestinal smooth
muscle.
These recording bandwidth settings are recommended:
- fEPSPs: 1Hz -10 kHz 
(1Hz - 2.5 kHz is acceptable to achieve even better signal-to-noise ratio.)
- Neuron spikes (single unit): 100Hz - 10 kHz
- Cardimyocyte signals (FPD analysis): 1Hz - 1 kHz (To achieve the stability for the K
+
release peak time) 
Avoid recording with lower bandwidth than indicated above.
Gain Setting
Raw signals are amplified by x10 with the 64-CHANNEL HEAD AMPLIFIER, then sent to the 64-CHANNEL MAIN
AMPLIFIER. The Gain at the Main Amplifier is set in the Mobius software by changing the “Input Range” at the
Mobius’ [Acquire MED64R2 Data] or [Acquire MED64R2 Data w/Stim] control panel.
The “Input Range” selected by the Mobius shows the maximum level of input signal. For example, if 5.0 mV is
selected, any signals larger than 5.0 mV are NOT acquired. T
he smaller the maximum input signal levels
are, the larger the gain is. The following chart shows the gain that can be achieved by each maximum input
signal level (Input Range) as well as the input signal resolution.
The following Input Range settings are usually recommended:
-fEPSPs: 5.0 mV
-Neuronal spikes (single unit): 2.3 mV
-Cardiomyocyte signals: 2.9 mV, Change to 5.0 mV depending on the size of your signal.

(e.g. Select 5.0 mV when 1 Hz - 10 kHz is selected for recording bandwidth.)
Gain
Maximum input signal level
(Input Range set with Mobius)
Input signal resolution
x217 2.3 mV 0.07  V
x172 2.9 mV 0.09  V
x100 5.0 mV 0.15  V
x40 12.5 mV 0.38  V
x20 25 mV 0.76  V