BrcParcellation: BrcParcellation constructor

Description Usage Arguments Details Value

Description

BrcParcellation makes a new BrcParcellation instance.

Usage

1
BrcParcellation(dim3d, partition)

Arguments

dim3d

a 3-element numeric specifiying the dimensions of the 3D fMRI volume

partition

a vector specifying the partition of the 3D fMRI volume. It must have as many elements as there are 3D voxels specified in the dim3d argument. Its values must be {0, 1, ..., n} where n is the number of columns in the two-dimensional fMRI data matrix.

Details

A BrcParcellation datatype contains all the information needed to map a two-dimensional fMRI data matrix (time x voxels) to a four-dimensional series of fMRI volumes (length x width x height x time). It is a list with two named components:

  1. dim3d, the dimensions of the 3D fMRI volume (length x width x height)

  2. partition, a vector assigning columns in the 2D data matrix to voxels in the 3D fMRI volume. The purpose of the partition is to allow one to group the 3D fMRI region into "parcels", making the 2D data matrix smaller. More details on the partition below.

Because BrcFmri is a dataype, not an object there are no accessor functions. You can get its components directly with the $ operator.

partition details: partition is a vector with one entry for each voxel in the 3D fMRI volume, and with values {0, 1, ..., n}, where n is the number of columns in the two-dimensional fMRI data matrix. A "0" entry in the partition marks the corresponding 3D voxel as being empty, i.e. it is not specified in the 2D data matrix and it has an implicit value of 0. Otherwise, the (postive) number marks the column in the 2D data matrix that contains the data for that 3D voxel. Since the vector is 1-dimensional and the fMRI volume is three-dimensional, we adopt R's convention of listing the voxels in column-row-depth order.

Value

a new BrcParcellation instance.


cdgreenidge/brcbase documentation built on May 13, 2019, 2:40 p.m.