= Fastgraph =
''Authors: John Mosher, Ken Taylor, Richard Leahy''

''' THIS TUTORIAL IS CURRENTLY UNDER CONSTRUCTION'''

<<TableOfContents(3,2)>>

== Introduction ==
Single-pulse electrical stimulation, or SPES, is used to study how stimulation at one brain site evokes activity across other implanted regions. In SEEG recordings, these stimulation-evoked responses are often measured from many contacts across multiple stimulation sites, making them difficult to review using conventional waveform displays. The Fastgraph, or '''F'''unctional-'''A'''natomical '''ST'''acked area graph, provides a compact way to summarize these responses by displaying them as stacked area plots organized using anatomical information.

In each Fastgraph, a subplot represents the response to stimulation of one contact pair. The recorded responses from other contacts are rectified, stacked, and displayed over time. Contacts can be separated by hemisphere, sorted according to response strength within a selected latency window, and colored by anatomical region or cortical label. Within Brainstorm, this process combines SPES recordings, SEEG contact locations, and anatomical labels to help users compare responses across stimulation sites, identify regions with prominent evoked activity, and review large stimulation protocols more efficiently.

Please note that this tutorial is intended for users already familiar with Brainstorm. It does not provide detailed explanations of the software's interface or theoretical foundations. For comprehensive introductory material, refer to the [[http://neuroimage.usc.edu/brainstorm/Tutorials#Get_started|Brainstorm introduction tutorials]].

=== License ===
This EEG, MRI, and CT data provided in this tutorial remain the property of !Cleveland Clinic, Ohio, USA. Use or distribution of this dataset outside the scope of the Brainstorm tutorials - including for research purposes - is strictly prohibited without prior written consent. For inquiries regarding permissions, please use the [[https://neuroimage.usc.edu/forums/|Brainstorm user forum]].

=== Clinical description ===
A 39-year-old ambidextrous female with medically refractory seizures presents with seizures consisting of a loss of awareness. Scalp video-EEG monitoring showed interictal epileptiform discharges arising from both left and right anterior temporal regions. The typical clinical seizures showed ictal EEG changes that were classified as left frontotemporal, right frontotemporal, or non-localizable.

Has the following steps:

 1. Load Single-Pulse Electrical Stimulation (SPES) from raw data
  * Separate ODD and EVEN events
 1. Remove Single-Pulse Electrical Stimulation (SPES) artifacts and slow drifts:
  * Detect stimulation events from a selected trigger channel
  * Replaces the artifact window around each event using spline interpolation
  * Apply Empirical Mode Decomposition (EMD) based filtering to remove low-frequency drift components
 1. Import ODD and EVEN events from the cleaned data
 1. Average ODD and EVEN events each ('By trial groups (folder average)' option)
 1. Average the ODD and EVEN together ('Everything' average option) so that we get a single averaged data file
 1. Plot Fastgraphs for the individual averaged file above.