Biomedical Engineering Reference
In-Depth Information
behavioral management efforts at the level of the animal
housing area/room, social group or the colony type
(conventional, specific pathogen free (SPF), etc.), rather
than having records for each individual.
Figure 6.4
illus-
trates an example of enrichment documentation at
a desired food item immediately after they present the thigh
to the trainer. There is no coercion or physical restraint
used, and there is no consequence to the animal if they
choose not to participate. Laule and colleagues (
Laule
et al., 2003
) have presented a detailed description of the
application of PRT for captive primates.
the
University of Texas, MD Anderson Cancer Center.
There are several ways in which documentation can be
accomplished. In some facilities, daily observation sheets
are used to document the provision of enrichment and other
behavioral management strategies. Other facilities collect
quantified, reliable observational behavioral data on indi-
viduals, including information on both abnormal and
normal behavior. This information is then often used to
document behavioral problems among the NHPs and to
determine the effectiveness of therapeutic interventions.
Handheld devices such as personal digital assistants
(PDAs) or wireless computer tablets can allow behavioral
observations to be seamlessly integrated into databases
containing the animal records. It is possible to maintain
a “behavioral record” for each animal that is similar to and/
or part of the animal's medical record (
Jennings et al.
2009
). While not every facility maintains these sorts of
records, most facilities are moving toward this goal (see
Chapter 11). The National Primate Research Centers are
moving towards harmonizing animal care records so that
data can be shared across facilities.
Because primates often behave differently in the pres-
ence of human observers than they do when no humans are
present (
Line, 1995; Iredale et al., 2010
), videocameras can
be an effective tool for documenting behavior. Behavioral
data recorded by videocameras and subsequently analyzed
can be effective for determining whether subjects are using
enrichment and if enrichment is altering behavior.
However, videotaped behavioral data are often quite time-
consuming and tedious to analyze. Further, videocamera
equipment can be novel and even potentially aversive to
some individuals (e.g. camera lenses can look like a big eye
and power cords can appear similar to snakes), and there-
fore, animals should be habituated to the presence of these
items before they are used to collect data.
PRT as Refinement
Positive reinforcement training can reduce the stress
associated with common management and research
procedures (
Bassett et al., 2003; Laule et al., 2003;
Schapiro et al., 2003
), and as such represents a significant
refinement, according to the 3Rs presented by Russell and
Burch (
Russell and Burch, 1959
). PRT desensitizes animals
to potentially stressful stimuli, such as injections (
Schapiro
et al., 2005
), thereby reducing fear and anxiety related to
these procedures. In addition, by allowing individuals to
cooperate with the procedures (i.e. they can choose
whether they want to participate), positive reinforcement
training gives animals greater control over their environ-
ment (
Laule et al., 2003
), a factor that typically reduces
stress (
Mineka et al., 1986
). Studies have demonstrated
reductions in both physiological and behavioral indices of
stress with the use of PRT. Chimpanzees trained to
voluntarily accept an injection of anesthetic (Telazol
)had
lower hematological indicators of stress (e.g. neutrophils
and white blood cells, glucose levels) than untrained
chimpanzees had (
Lambeth et al., 2006
). Training has also
been shown to reduce the animals' stress for procedures
other than the task for which they were trained. Marmosets
trained to provide urine samples displayed fewer behav-
ioral indices of stress (e.g. scratching) in response to
capture and weighing than untrained counterparts (
Bassett
et al., 2003
). Savastano and colleagues (
Savastano et al.,
2003
) reported a decrease in threat behavior toward care-
takers after initiation of a PRT program for several species
of New World monkeys. Results of these studies support
the idea that PRT can promote overall well-being and
welfare.
There are other ways in which PRT is a useful refine-
ment. Training can reduce the need for sedation for
procedures, such as venipuncture and weighing. Stress
associated with pharmacological agents such as ketamine
HCl, commonly used for sedating monkeys, have been
correlated with increased cortisol levels (
Crockett et al.,
1993, 2000
), decreases in leukocytes (
Hall and Everds,
2003
), and decreases in appetite after recovery (
Crockett
et al., 2000; Springer and Baker, 2007
) in various macaque
species. All of these changes can adversely affect various
research paradigms. Training can also allow research
animals to be socially housed; trained animals are easier to
access, even for biological sampling. By reducing the stress
associated with husbandry and handling procedures,
POSITIVE REINFORCEMENT TRAINING
Like environmental enrichment, positive reinforcement
training (PRT) should be an important component of
a comprehensive behavioral management program. PRT
techniques take advantage of the stimulus-response-
reinforcement contingency that is a principle of operant
conditioning (
Skinner, 1938
). Positive reinforcement refers
to the provision of a “reward” (reinforcement) that is likely
to increase the frequency of the target behavior (response)
once a signal (stimulus) has been given. Primates trained
using PRT techniques are typically asked to perform
a behavior (e.g. “present a thigh”) and are then given
