# Baseline markers The beginning and end of the eyes open and eyes closed periods are recorded via markers in data stream as interval markers. An interval marker has a start time as well as a duration. The start times of all markers are shown as vertical pink lines in the EEG data recording shown in Raw EEG and Motion views. The exact location can be seen in the "markers" file that is exported with the data, if requested. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://emotiv.gitbook.io/emotivpro-v3/event-markers/baseline-markers.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.