Multichannel Systems MEA1060-Up-BC Manual - Manual (Page 37)

Troubleshooting
37
Wait settings
A delay (up to 5000 μs) between stopping stimulation (end of TTL pulse) and restarting the
recording can be programmed with the Wait property in the MEA_Select program in order to
optimize the blanking. The stimulation electrodes are disconnected from the stimulus input
at the end of the trigger signal, and all electrodes are connected to the amplifier input at
the end of the Wait period.
The Wait helps avoiding cross-talk between stimulating and non-stimulating electrodes as well as
preventing switch artifacts of the amplifier.
The length of the Wait depends on several factors (electrode performance, stimulus amplitude,
for example) and has to be optimized empirically for each experimental setup. Generally, the
lower the amplitude of your stimulus is, the shorter can be the blanking signal. For strong stimuli,
a Wait of up to 400 μs can be necessary.
A factory-set Wait of 40 μs is added to all user defined Wait values. For example, a user-defined
Wait of 0 results in a total delay of 40 μs.
Electrode impedance
A parameter that was found to be quite important for the stimulus artifact suppression
performance is the electrode impedance. Electrodes that are bigger (30 μm) or TiN electrodes
show a better blanking performance compared to very small (10 μm) or PT electrodes (3D-MEAs)
with a higher impedance. Please note that a hydrophilic electrode has a lower impedance and
therefore also shows a better blanking performance. New MEAs are generally very hydrophobic
and should be hydrophilized before use (please see the MEA manual for more information).
Note: When using current driven stimulation, the combination of electrode impedance and
current amplitude may lead to high voltages. Please regard the maximum input voltage of
5 V of the MEA1060-BC amplifier. Otherwise, an unpredictable behavior of the amplifier
can be expected. In rare cases, even damage to the amplifier electronics might occur.
MCS recommends to use
voltage driven stimulation only .