LiveAmp with Sensor & Trigger Extension for GSR signal recording

The LiveAmp is an ultra-lightweight, wearable amplifier that can record referential EEGClosed Electroencep- halography channels and bipolar channels. BPClosed Brain Products GmbH sensors can be used with the LiveAmp in combination with the Sensor & Trigger extension, providing 8 AUXClosed Auxiliary channels ( Figure 8 ).

Figure 8 LiveAmp and LiveAmp Sensor & Trigger extension. The GSR module is connected to one of the AUX ports of the Sensor & Trigger extension.

The BrainVision Recorder workspace should be set as in Figure 9 for GSRClosed Galvanic Skin Response recordings, given the following considerations.

The lowest available sampling rate is sufficient to record the GSR signal. However, the sampling rate set in the workspace applies to all recorded signals. If GSR is recorded simultaneously with other signals, e.g. EEG, a higher sampling rate may be required depending on the specific application. If needed, downsampling can be easily applied to the GSR signal offline.

The correct physical channel number must be indicated in the column “Phys. Chn” of the channel table ins the workspace. The AUX channels always correspond to the last 8 physical channels, therefore in the BrainVision Recorder workspace settings, if you have a LiveAmp 32, the AUX channels will correspond to physical channels 33-40, if you have LiveAmp 64, the AUX ports will be physical channels 65-72 ( Figure 9 ).

In order to set the correct units, gradient and offset in the channel table, check the box “Diff. Unit”, write “µS” as “Unit”, 25 as “Gradient” and 0 as “Offset”.

The other settings are dependent on your individual experimental requirements. For additional information about setting up a BrainVision Recorder workspace, please refer to the Recorder user manual.

Figure 9 BrainVision Recorder workspace settings for recording GSR with LiveAmp: in the channel table check the box “Diff. Unit”, write “µS” as “Unit”, 25 as “Gradient” and 0 as “Offset”. The other settings are dependent on the individual experimental requirements.