Brain Voyager: Brain Tutor is the freeware version of a more full-scale application that offers visualisation and analysis of fMRI data. Brain Tutor is a bit simpler than that: with only one subject’s MRI data pre-loaded, you can simply zoom around the brain in 3d, and click on various bits to have them highlighted. Additionally, a brief blurb pops up pointing out the main functional areas of the highlighted area. This can be hugely helpful in understanding how the brain actually looks. Schematic, two-dimensional maps typically do a poor job at explaining this.

That being said, the Brain Tutor is a little bit hard to understand. It comes with very little documentation, and unfortunately, some keyboard shortcuts are given incorrectly (at least on the Mac version), while other shortcuts are not described at all. More on this later. This page aims to give you a general overview of what I’ve figured out about Brain Tutor so far.

The Main Interface
Brain Tutor really only consists of one window that you work in the whole time. (click for bigger version):

The large main window is where you change your viewing angle and position, and where you can highlight specific areas in the 3d mode. The sets of buttons below toggle the viewing mode and what type of area gets highlighted when you choose it. For example, here I’ve highlighted some sulci in the prefrontal cortex:

Here are the same highlights, in orthographic mode:

Interface Buttons
There are 4 sets of buttons below the main window, with which you set your viewing mode. By holding your mouse over either, a popup appears explaining its purpose. The button sets are:

The first set of buttons lets you toggle the display mode between the typical medical orthographic slice display mode (left), and the 3d-rendered surface rendering display mode. Note that you can only highlight areas in 3d mode, but the higlights carry over to orthographic mode.

The second set of buttons determines the direction of the slice in 3d mode: Axial (top to bottom), Coronal (front to back), or Saggital (left to right).

The third set toggles the rendering of the two hemispheres in 3d mode. If both these are off, you will simply see a flat orthographic image of the brain at the slice point.

Finally, the fourth set of buttons toggles what you want to highlight in 3d mode. From left to right, your options are: lobe selection, gyri selection, sulci selection, and gyri and sulci selection. The final two buttons are supposed to toggle brodmann areas and functional areas selection (that would be so cool!), but these features haven’t been implemented yet.

Keyboard Shortcuts (OS X)
These shortcuts have only been tested on a Mac. Try substituting command for ctrl on other machines.

• Left Mouse Button: Move image
• Shift-Command-Left Mouse Button: Zoom in our out by moving mouse
• Shift-LMB: Rotate image by moving mouse
• Command-LMB: Highlight area (click again to remove label)
• A: Toggle visual aids in 3d mode
• Z, X: Manipulate slice point in 3d mode

The final slice point shortcuts don’t appear anywhere in the documentation, yet it’s quite a nice effect for showing off: go into coronal slicing mode, hold down Z, and watch the subject’s face gradually rebuild, slice by slice.

Conclusion
Brain Tutor is an impressive and quite helpful application. Unfortunately, it suffers from a slightly confusing interface, and some omissions in documentation. Hopefully this guide has helped clear things up. Have you figured out how to do something else in Brain Tutor? Let me know!