Knowledge Base

Aligning Data

To align the data streams from EthoVision XT and Inscopix nVista/nVoke, there are two solutions:

• Have EthoVision XT send a time code signal (TCAP).
• Have EthoVision XT send a sequence of TTL pulses.

Either way, the Inscopix system records the signal in one of its channels. The difference between the two is that with TCAP you need to export the TCAP signal that is stored in Inscopix back to EthoVision XT, together with the Inscopix data, so that EthoVision XT reads the time code and aligns the Inscopix data with the tracks.

Note: The nVista/nVoke system can also send a sync pulse to EthoVision XT through the USB-IO box every time a video frame is recorded. However, the pulse generated from the SYNC port of nVista/nVoke has a duration of 10 ms. That is too little for EthoVision XT to detect and record the signal. Therefore, this solution is not optimal to sync the two data streams.

Using the TCAP Signal

Prerequisites

For this solution you need:

• The External Data add-on module for EthoVision XT. Contact Noldus if you need to purchase it.
• An interface cable between EthoVision XT and the BNC connector of the nVista/nVoke DAQ box. Contact Noldus to have one made for you.
• A way to convert the Inscopix data to a format compatible with EthoVision XT: fixed sample rate, without gaps.

Procedure

1. Set the TCAP signal in the Experiment Settings of EthoVision XT, and specify the sample rate of the Inscopix channel that will receive that signal.
2. Start acquisition in Inscopix and then start the trial in EthoVision XT. nVoke/nVista records the TCAP signal, which should be visualized on the system's screen.
3. Export the Inscopix data to text files. Note that here the sample rate must be fixed and all samples must be written in the file, otherwise import won't work.
4. After import, EthoVision shows the TCAP signal and other Inscopix data together with the track data.

For more information, see External Data in the EthoVision XT Help.

Using a TTL Signal

Connections

Connect a TTL port of the USB/IO box to one of the GPIO ports of the Inscopix DAQ box. For this you need a cable with a RJ45 connector at one end and a BNC connector at the other end.

Procedure

1. In the Experiment Settings in EthoVision XT, define a TTL port of the USB-IO box. Select Custom Hardware from the list. In the Arena Settings, map that TTL port to one of the arenas.
2. In the Trial Control Settings, add a subrule that activates the TTL port every few seconds. For example: TTL Output 1 High for 1 second, then TTL Output 1 Low for 4 seconds. Let the subrule repeat a number of times or when a Trial Control variable reaches a specific value. In general, make sure that the ON-OFF sequence runs through the duration of the trial.

   Tip: To stop the subrule at the end of the trial, add an Action box immediately before the Stop Trial box, where a Trial Control Variable (for example END) gets the value 1. In the Subrule reference, specify to end the subrule when END = 1.

3. Run a test trial and make sure that Inscopix records the signal coming to the GPIO port.
4. Visualize the data in both systems. In EthoVision XT, you can visualize the TTL signal by selecting, for example, Trial Control State in the Analysis profile and defining the state from the action Output 1 High to the action Output 1 Low (the numbering depends on which TTL line you use).
5. If the data are well aligned, the time between the first and the last pulse should be the same in EthoVision XT and Inscopix, or differ by a few milliseconds.

For More Information

• The nVista/nVoke User Manual.
• The EthoVision XT 18 - Trial and Hardware Control - Reference Manual.

Mark EthoVision Events on the Calcium Imaging Timeline

You can also use the GPIO ports on the nVoke/nVista box to send specific events to the Calcium Imaging software.

In the following example, a setup that includes a fear conditioning system, all GPIO ports are set to digital and work as inputs:

• GPIO-1 receives a signal from a TTL port of the USB-IO box that is set to high when tracking starts.
• GPIO-2 receives a signal from a TTL port of the USB-IO box that is set to high when a 5-kHz tone is given.
• GPIO-3 receives a signal from a TTL port of the USB-IO box that is set to high when a 15-kHz tone is given.
• GPIO-4 receives a signal from a TTL port of the USB-IO box that is set to high or low when the optogenetic stimulation is given/stopped, respectively, or when a shock is given/stopped, respectively.

Source: EthoVision XT 18 - Application Manual, Noldus Information Technology