Multichannel Systems MEA2100-System Manual - Manual (Page 20)

MEA2100-System Manual
16
Blanking
A blanking signal transiently switches off the input stage of the amplifier during the stimulus,
thus avoiding stimulus artifacts on non-stimulating electrodes.
Amplifier saturation is effectively prevented and the recovery time is greatly reduced. During
the blanking period, a flat line is displayed. This blanking period extends a few hundred
microseconds before and after the actual stimulus, currently 600 μs, but might be subject to
change. The pre- and post-time are experimentally optimized and can not be changed by the user.
Dedicated Stimulation Electrodes
The function “Dedicated Stimulation Electrodes” can be used to further avoid stimulation artifacts
on the electrodes surrounding the stimulation electrode which are sometimes not completely
removed by the blanking alone. Usually, the stimulation electrode will be connected to the
stimulator output only during the stimulation pulse, and afterwards be switched back to the
amplifier to be used as recording electrode. This sometimes causes switching artifacts
independently from the actual stimulation.
However, if the function “Dedicated Stimulation Electrodes” is active, the selected stimulation
electrodes will be constantly connected to the stimulator outputs. This causes permanent higher
noise on the selected stimulation electrodes, and makes of course recording on the stimulation
electrodes impossible, but almost completely removes residual artifacts. The images below show
stimulation on electrode F3 with and without “Dedicated Stimulation Electrodes” activated.
Note: The artifact suppression additional to blanking via “Dedicated Stimulation Electrodes”
is not available when using the “List Mode”.
“Dedicated Stimulation Electrodes” selected (X-Axis: 1000 ms, Y-Axis: +/- 500 μV).
“Dedicated Stimulation Electrodes” deselected (X-Axis: 1000 ms, Y-Axis: +/- 500 μV).