brain {gamair}

Brain scan data

Description

Functional magnetic resonance imaging measurements for a human brain subject to a particular experimental stimulus. One slice of the image is provided, described as a near-axial slice through the dorsal cerebral cortex.

Usage

data(brain)

Format

A data frame with 5 columns and 1567 rows. Each row refers to one ‘voxel’ of the image. The columns are:

X

voxel position on horizontal axis.

Y

voxel position on vertical axis.

medFPQ

median of three replicate 'Fundamental Power Quotient' values at the voxel: this is the main measurement of brain activivity.

region

code indicating which of several regions of the brain the voxel belongs to. The regions are defined by the experimenters. 0 is the base region; 1 is the region of interest; 2 is the region activated by the experimental stimulus; NA denotes a voxel with no allocation.

meanTheta

mean phase shift at the Voxel, over three measurments.

Details

See the source article for fuller details.

Source

S. Landau et al (2003) ‘Tests for a difference in timing of physiological response between two brain regions measured by using functional magnetic resonance imaging’. Journal of the Royal Statistical Society, Series C, Applied Statistics, 53(1):63-82