CHAPTER 5 
Experimental Enclosures and 
Physical Restraint 
TYPES OF APPARATUS 
Most behavioral experiments involve transferring the animal to a specially constructed 
apparatus, such as an operant chamber ("Skinner box"). There is a long tradition of studying 
the behavior of rodents in various kinds of mazes (including a water maze), running wheels, 
or open field areas (Porsolt et al., 1993). Whatever specialized chamber is used, the animal 
remains in it for the duration of the experimental session, and then is returned to the home 
cage. Such apparatus is usually interfaced to a computer and equipped for presentation of 
stimuli (e.g., lights, sounds, food pellets) and to record behavior (e.g., lever operation, licking 
a spout, locomotor activity). Depending on the experiment, the apparatus into which the 
animal is placed may or may not be placed inside a larger chamber that is designed to 
attenuate extraneous visual or auditory stimuli during the experimental session. Ator (1991) 
reviewed the use of chambers and other apparatus. 
Some behavioral experiments require restriction of movements during the experimental 
session. For example, restraint is commonly used in cognitive or neurophysiological 
experiments that use awake, behaving monkeys to study sensory function, perception, 
learning, and memory. In such experiments, it is important to ensure a consistent orientation 
toward and precise distance from sensory stimuli. In those cases, a specially designed sling or 
chair may be used. Head restraint may be used if it is important that the animal (usually a 
monkey) look at a fixation point on a video monitor so that eye position can be monitored 
and/or if activity of the central nervous system (e.g., electrical activity of brain cells) is being 
monitored during the behavioral task. Often the chair itself will incorporate devices (levers, 
lights, feeders) needed during the experimental session. In other situations, the chair is 
wheeled in front of an intelligence panel. 
In other types of behavioral experiments, the animal's activity may be restrained by means of 
a tether. For example, in intravenous drug self-injection experiments or ones that require 
intra-gastric drug delivery, the animal (e.g., rat, mouse, monkey, dog) may have been 
implanted with a chronic indwelling intravenous or intragastric catheter (e.g.. Lukas et al., 
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