Introduction

Markers typically signal the onset of significant events in a task. They are sent from the stimulus presentation PC to physiological data acquisition devices such as Biopac or Biosemi and are used to segment the physiological data in meaningful segments.

Sending Markers

UsbParMarker and Eva

The markers_os4 plugin (for OpenSesame 4) and markers_os3 plugin (for OpenSesame 3) can be used to send markers from OpenSesame with a UsbParMarker or Eva device to equipment like Biopac or Biosemi. Make sure to use the correct version of the plugin: when using OpenSesame 4, see here for more information on how to install and use the plugin, and when using OpenSesame 3, see here for more information. Using a UsbParMarker or Eva to send markers is recommended for Leiden University FSW researchers.

Alternatively (but not recommended) one can use inline Python to send markers from an inline item in OpenSesame using the example here.

LPT

Alternatively, markers can be sent through parallel port. This is not recommended because it is not built into modern computers. It also requires the installation of a driver, which is not installed on lab computers at FSW Leiden by default. When installation of LPT hardware and the driver on a lab pc is necessary, please contact SOLO researchsupport. More information on the installation of the driver and how to send markers to the parallel port can be found here: Parallel port (EEG triggers) // OpenSesame documentation (cogsci.nl).

Other devices

For synchronization with other devices see:

• Tobii: Tobii and OpenSesame
• EyeLink: EyeLink and OpenSesame
• VU-AMS: VU-AMS and OpenSesame