d3view Users tutorial (4): Understanding the imaging problem - activation

In this part of the tutorial we explain how functional activation data can be presented on the anatomical 3d object defined in the previous part of the tutorial.

Let us imagine that an activation dataset coregistered with the anatomical dataset has been loaded. In d3view, activation data can be added in three different but combinable ways.

Surface activation

Activation on the surface of the brain is controlled using the "PET penetration depth" dialog, which appears by pressing the "Depth profile" button on the d3view control window.

Surface activation profile

Each point on the brain surface is coloured using a weighted average of the underlying activation data. Any mathematical expression (in matlab syntax) can be used to sample the underlying activation data across any number of points to any depth below the brain surface.

Here is an example of the resulting surface activation:

Surface activation added

Slice activation

If a part of the brain surface is selected invisible, the anatomical data are presented on the three intersecting planes. Activation data can be presented on the resulting slices:

Slice activation added in octant 2.

Blob activation

Activated areas of the brain can be visualized by selecting a certain activation threshold. Activation above the selected threshold is encapsulated in so called activation blobs. An example of an activation blob is presented here:

Blob activation added. Octant 2 is selected invisible.

Parts of the brain surface must be selected invisible in order to reveal blob activation - in this case octant number 2 was selected invisible.

Next tutorial item: Rendering Parameters.