Screenshots

MEG somatosensory evoked responses

Acquisition on an CTF 275 instrument for a left median nerve electric stimulation.

Keeping your data organized and accessible

The tree in the main Brainstorm window represents the database for the selected study. This database has three levels of definition: Protocol (ie. study, selected in the toolbar), Subject, and Condition. Most of the operations that can be performed on a file are easily accessible from the popup menu revealed by right-clicking over the file.

The first three buttons in the toolbar allows the user to switch between different views of the same database:

• Anatomy: display the MRI and surfaces for each participant in the study
• Functional data (sorted by subject): sensor definitions, MEG and EEG data, source models, statistic and time-frequency maps
• Functional data (sorted by condition): same as above, but sorted in a different way

The following example features a MEG+EEG protocol called "Catching", sorted by conditions. There are two experimental conditions, Catch and NoCatch, and 7 subjects per condition. The popup menu shows all the actions that are available for the recordings of subject cc, condition Catch.

Multiple conditions: Baby auditory EEG responses

Acquisition system: EGI GSN - Baby 64 electrodes

Description:

• One subject: "001"
• Three conditions: "GM", "GMM", "VM"
• Two views: overlaid electrodes time series, and estimated cortical sources at t=376ms

Subject anatomy: MRI and surfaces

Brainstorm features the possibility to model MEG and EEG neural generators either from the individual subject anatomy, or by using a template anatomy (MNI / Colin27) that can be warped to the individual scalp surface. Multiple interactive tools are available to view, register and process the MR images and the corresponding tessellated envelopes. However, tissue segmentation must be performed using another software; multiple options exist today in the academic community (?listed here).

We provide a few examples of the views you can easily obtain with Brainstorm. All the 3D views can be rotated freely with the mouse, zoomed with the wheel, edited with the "Surface panel" and contextual popup menus. The MRI slices can be browsed with a simple mouse operation: right-click and mouse drag.

Channel selection

All the figures displayed by Brainstorm are linked in time. If they feature the same dataset, the sensor selection is also the same for all views. The selection of a channel subset can be easily perfomed by clicking on the corresponding channels in a time series display or a 3D view. Selected channels can be displayed separately, marked as "bad", or deleted.

Online bandpass filtering

Recordings and sources: 40Hz low-pass filtering with the "Filters" tab in main Brainstorm window.

Defining cortical region of interest: Scout

Acquisition system: CTF MEG - 151 sensors

Scouts are cortical regions of interest, defined graphically from the "Scouts" tab. They can be used to extract the time series of MEG and EEG generators within a single or mulitlple brain region.

The following example shows the cortical response to an electric stimulation of the left index finger. With the two scouts Left and Right, one can observe the electrical activity in the primary somatosensory cortex from each hemisphere.

Scouts: browsing through multiple conditions

Acquisition system: CTF MEG - 151 sensors

Same experiment than in the previous example, now showing the responses for two conditions: Left-1 (electric stimulation of the left index finger) and Left-4 (left ring finger).

From surface to volume: MRI integration

Acquisition system: CTF MEG - 151 sensors

Same experiment as above, with additional 3D display of the scout activity in MRI slices.

Time-frequency decompositions

Acquisition system: CTF MEG - 151 sensors

Time-frequency decompositions of sensor data and source time series, extracted from cortical regions of interest.

Standardization: z-score

Acquisition system: EGI GSN - Baby 64 electrodes

The "Processes" tab in the main Brainstorm window allows users to apply multiple processes to a set of data or source maps. Just drag and drop files from the database tree to the box in the "Processes" tab, and click on "Run" to start the processing.

The function that was applied here is a simple z-score standardization.

The top-right figure displays the initial sources estimate, and the bottom-left figure shows the corresponding z-score valued source map.

Statistical inference: t-test maps

Acquisition system: EGI GSN - Baby 64 electrodes

The "Processes" tab can also be used for running statistical tests e.g., to evaluate contrasts between two experimental conditions.

The following example features the evaluation of the difference between conditions GM and GMM, from the source maps of mulitple subjects (paired Student t-test, p<0.05). The top figure shows the significance of the difference at the sensor level across time. The bottom figure displays the thresholded t-values at the cortical level at 280ms.

This image also illustrates the "Coordinates" tab: It is possible to pick any point from any surface by clicking on it, and immediately get its coordinates in all the coordinates systems used by Brainstorm (MRI, Subject's head and Talairach).