Spot Inserter From List

By right mouse clicking on the traces area a popup menu will be shown. The same menu items are also accessible from the “Traces” menu while in EEG mode. It allows, among the others, to select four different modalities to automatically (or interactively) insert events based on some properties of the acquired signals

By selecting the "Spot Inserter From List…” item will make the following Dialog Box appear:

This modality is useful when one uses for example an external stimulation software and can send a trigger whenever a stimulus is generated. In this case the acquisition software does not have any information regarding the nature of each stimulus, but only its onset. So, it is possible to provide an external list (text file, one event per line) in which the sequence of the stimuli is provided. It is then possible to match triggering event with the external list in order to bind the stimulation time with the stimulation type in order to create the relative events.

There are two main steps in this modality: the detection of the exact event time and its labelling (type). To detect the event time there are two options:

1. By Events Selection, which means that the timing (but not the type) of the events is somehow already stored into events. Usually this may occur if an acquisition device is capable to automatically identify only one external trigger type and already insert an event of a predefined type (e.g. "External Trigger"). In this case one has to identify the event type that will be used to copy the timing information from the "To Use" list. It might occur, sometimes, that the acquisition device misses some triggers. If you encounter such problem you can insert by hand the missing event (see the Manual Event Insertion page) and select it from the "To Skip" list. Note that this event will not be inserted, so that accurate timing is not required. But this is necessary if you have a very long list and you discover that one event (e.g. the 1257th) was not detected by the system. In this you have two options: you create a new list of events without the 1257th event, or simply you can insert an event by hand of a different type (e.g. "Missing") and select it from the "To Skip" list. In this case your original external list of stimuli should be left unmodified.
2. By Channel Threshold, which means that a timing event is identified every time a certain threshold condition is detected on a specific sensor (Greater or lower than a defined value).

Finally, to label the events (that is, to assign them to their proper types), an ASCII file should be loaded, containing one label per line (shorter than 255 characters). Usually one wants to insert Spots events (instantaneous events), but is is also possible to insert States (their duration is greater then 0) if the system inserts triggers at the beginning and end of some epochs. A state is inserted every two triggers, so the ASCII list file should contain a number of lines (event labels) which is half the number of triggering events.

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