Create Volume Time course files (VTCs)

In this chapter the following topics are available:

 

Create VTC in Talairach space

Script to quickly create 3 VTCs in Talairach space

Create VTC in AC-PC space

Create VTC in native space

Parameters for creating VTCs

Create multiple VTCs script

 

Introduction

There are three scripting methods in BrainVoyager QX 1.3 to create a volume time course file (*.vtc). The three new methods can be used in different spaces. The CreateVTCinVMRSpace() will create a VTC in the original space, i.e. non-transformed space. As the name indicates, the CreateVTCinACPCSpace() will create a VTC file that can be used on a VMR in AC-PC space. The CreateVTCinTALSpace() method creates a VTC file in Talairach space.

These methods correspond to the possibility in the VTC File Creation dialog to leave out transformation the ACPC (*.trf) file and the *.tal file (see subtopics about VTCs).

Note: Although the extended bounding box is only applicable in Talairach space, do always set the parameter ExtendedTALSpaceForVTCCreation to true or false before starting to create any VTC, also when the VTC is created in VMR or AC-PC space! Because the size is undetermined if this parameter is not set.

 

When the VTC already exists, the method LinkVTC() can be used.

 

The last function for creating VTCs, the 'classical' one, is the CreateVTC() method. This is an adaptation of the inherited method in older versions of BrainVoyager comprising the use of initial and fine alignment transformation files (*_IA.trf and *_FA.trf), products of the hierarchical coregistration method introduced in BrainVoyager QX last year. This function will create a VTC in Talairach space. It is now obsolete.

Creating Non-TAL VTCs

VTCs are normally created in Talairach space but they can be also created in the space of the VMR file to which the original FMR has been coregistered or in ACPC space. When creating VTCs in these non-Talairach spaces in previous versions, the Talairach bounding box was turned off which resulted in filling the whole target volume with values although a lot of voxels were filled with zero values. In order to avoid filling a target volume with zeros wasting memory and disk space, the current version of QX now automatically turns on the "Use intensity threshold to find brain voxels" option. With this option turned on, the program checks the really required space in the target volume and adjusts the bounding box accordingly. The value for the intensity threshold is set to "100" as default, which works generally fine for original scanner data. If the intensities of your data sets have been scaled, you might want to adjust the threshold accordingly.

 

Methods

CreateVTCInVMRSpace(): Boolean

CreateVTCInACPCSpace(): Boolean

CreateVTCInTALSPace(): Boolean

LinkVTC(): Boolean

 

CreateVTC() (obsolete, replaced by methods mentioned above)

 

Properties

ExtendedTALSpaceForVTCCreation: Boolean (for CreateVTCInTALSpace() method)