rat.brain {WWGbook}R Documentation

rat.brain data in Chapter 5

Description

The data used in this example were originally reported by Douglas, et al. (2004). The aim of their experiment was to examine nucleotide activation (guanine nucleotide bonding) in seven different brain nuclei (i.e., brain regions) among five adult male rats.

Usage

data(rat.brain)

Format

A data frame with 30 observations on the following 4 variables.

animal
: Unique identifier for each rat
treatment
: Level of drug treatment (1 = Basal, 2 = Carbachol)
region
: Brain nucleus (1 = BST, 2 = LS, 3 = VDB)
activate
: Nucleotide activation (the dependent variable)

References

Douglas, C.L., Demarco, G.J., Baghdoyan, H.A., and Lydic, R, Pontine and basal forebrain cholinergic interaction: implications for sleep and breathing, Respiratory Physiology and Neurobiology, 143, 251, 2004.

West, B., Welch, K. & Galecki, A, Linear Mixed Models: A Practical Guide Using Statistical Software, Chapman Hall / CRC Press, first edition, 2006.

Examples

attach(rat.brain)

###Figure 5.1: Line graphs of activation for each animal by region within levels of treatment for the Rat Brain data.
region.f <- region
region.f[region == 1] <- 1
region.f[region == 2] <- 2
region.f[region == 3] <- 0
region.f <- factor(region.f)
treat <- treatment
treat[treatment == 1] <- 0
treat[treatment == 2] <- 1
treat <- factor(treat)
rat.brain <- data.frame(rat.brain, region.f, treat)

library(lattice)  # Load the library for trellis graphics.
# Load the nlme library, which is required for the 
# plots below as well as for subsequent models.
library(nlme)

rat.brain.g1 <- groupedData(activate ~ region | animal, 
outer = ~ treat, data = rat.brain)

plot(rat.brain.g1, display = "animal", outer = TRUE, aspect = 2, key = FALSE, xlab = "region", ylab = "mean activate", main="Treatment" ) 

[Package WWGbook version 1.0.0 Index]