Interacting with NIC

In this page we describe how you can interact with NIC (Neuroelectrics Instrument Controller, the software for control with NE devices) using other software.

Sending Markers to NIC from other software or hardware

Sending Markers using TCP/IP

NIC provides a server that other software can connect to in order to send markers. Those received markers are synchronized with the EEG streaming for further analysis.

This NIC server is running in the TCP/IP port 1234. Up to five clients can simultaneously send markers to NIC by making a TCP/IP connection to this port.

Once a client is connected it needs to send the following string in order to send a marker:

<TRIGGER>XXXX</TRIGGER>

Where XXXX can represent any integer number different from zero (from -2147483647 to +2147483647). This marker will be co-registered in the output files generated by NIC to the corresponding EEG sample. For instance, in the output tabulated text file, the column just after the timestamp one is filled with zeros if no markers are received. When a marker is received its corresponding number is set to that column. See the following example:

...
26748	-27675	35631	42398	532666	64345	12376	40988	0	1382432459788
26865	-26683	35685	42450	532711	64821	12376	41046	0	1382432459790
26810	-26821	35531	41997	532821	64945	13164	41099	0	1382432459792
26749	-26995	35325	42008	532712	64377	13478	41286	0	1382432459794
26796	-27245	35932	42391	532923	64245	13620	41117	300	1382432459796  <-- Reception of the marker #300
26622	-27510	35501	42630	532876	64193	13031	40986	0	1382432459798
26751	-27912	35611	42003	532345	64344	12967	40731	0	1382432459800
...

Plot of markers received by NIC and an audio signal recorded by Enobio

Please take as an example this Matlab code which connects to NIC to send markers every time a tone is played back through the sound card. If you connected the output of the computer sound card to one of the Enobio electrodes you would be able to see the alignment between the markers and the played tones.

Sending markers using LSL

NIC is compliant with the Lab Streaming Layer (LSL) protocol so makers can be co-registered with the EEG signal by setting up a LSL marker outlet (see this example).

The LSL handles both the networking and time-synchronization isues between the sender and receiver hosts obtaining reliability on order of 1 ms (see the time-synchronization validation tests).

NIC settings for configuring the reception of markers through LSL

NIC needs little configuration in order to receive the markers from a LSL outlet present in the local network. When the LSL marker outlet sends integer-type markers only the name of the outlet needs to be configured in NIC.

Please go to "EEG Setup -> Settings -> Markers from Lab Streaming Layer" and set the name that your LSL marker outlet has. NIC will automatically look for a marker outlet with this name and will connect to it. If the outlet sends integer-type integers then no further configuration is needed. All the received makers will be co-registered along with the EEG signal to the output files.

In case the outlet sends string-type markers then there are some considerations that have to be taken into account. The LSL outlet sending string-type markers has to format them as XML tags. The following example is taken from the string markers that the Presentation software sends when the LSL extension manager is installed (see the Working with ERPs section). You can see that NIC will decode the string looking for the tag that is configured in the "EEG Setup -> Settings -> Markers from Lab Streaming Layer" settings, ecode in this case.

<pevent><etype>Picture</etype><ecode>37</ecode><unc>209.638092041016</unc>test</pevent>