Trigger Optogenetic Stimulation with PlexStim and OmniPlex


Video showing the shanks of an opto/recording probe with LEDs that are illuminated in response to neural firing

Using the new OmniPlex SDKs with Release 18, we have designed an online closed loop experiment example in which the PlexStim electrical stimulator triggers optogenetic stimulation based on spike activity detected by OmniPlex.

The average spike rate client monitors unit A on OmniPlex channels 1-4 and creates a corresponding Digital Output that is high when the spike rate is above the set threshold. A cable is used to connect the OmniPlex Digital Output to the Stimulator Digital input. Each client channel controls three stimulator channels. The stimulator is connected to the electrodes such that stimulator channels 1-3 control the 3 LEDs on the first shank of the probe, stimulator channels 4-6 control the 3 LEDs on the second shank of the probe, etc.

The user can set the threshold sliders for each channel such that the different channels will cross threshold at different times. The average spike rate client examines the firing rate on each channel. When the channel crosses the threshold, the corresponding LED will be activated.