Ch. 6 — Alternatives to Animal Use in Research • 133 
USE OF LIVING SYSTEMS IN BEHAVIORAL RESEARCH 
In behavioral research, using living components 
derived from whole animals or living nonanimal 
systems as alternatives to animals could conceiva- 
bly involve embryos; cell, tissue, and organ cul- 
tures; invertebrates; and plants. The greatest po- 
tential in this area, however, appears to rest with 
the use of invertebrates. 
Several factors limit the use of embryos (used 
here to refer to the conceptus, embryo, and fetus 
prior to birth) as an alternative or complement to 
young or adult animals: 
• Some studies involving embryos may be con- 
ducted when the subject is very close to birth 
or hatching. The advanced developmental sta- 
tus of the organism at this point raises the same 
kinds of ethical considerations that would ap- 
ply to the use of postnatal animals (see ch. 4). 
• In behavioral studies involving mammalian 
embryos, the mother is necessarily involved 
in most experimental manipulations performed 
on the embryo. As a consequence, embryo - 
logical manipulations on mammals cannot log- 
ically avoid the use of adult mammals. 
• Behavioral studies using embryos may involve 
testing for effects later in adult life (e.g., be- 
havioral teratological studies). In these in- 
stances, embryos are not being used as alter- 
natives, since the procedures also require 
postnatal assessment. 
• Only a limited number of behaviors can be 
studied in embryos, partly because of practi- 
cal problems associated with access to the 
embryo. 
• Embryos live in a dramatically different envi- 
ronment than fully developed adult animals. 
This difference constrains the generalizabil- 
ity of behavioral data obtained from them. 
Cell, tissue, and organ cultures do not figure 
prominently in the equation of alternatives to ani- 
mal use in behavioral research. In isolation and 
in culture, cells, tissues, and organs exhibit few 
activities that fall among the disciplines of be- 
havioral research. 
A rare example of the use of cell culture in be- 
havioral research comes from studies of the bio- 
chemical basis of depression and manic mood 
changes. Skin fibroblast cells obtained from hu- 
mans and maintained in culture for several months 
were assessed for their ability to bind a variety 
of pharmacologic agents. The cultured cells of pa- 
tients and relatives of patients with manic-depres- 
sive illness exhibited markedly different biochem- 
ical properties than the cultured cells of persons 
without a history of manic depression (155). One 
commentator characterized this as “a step forward, 
applying to psychiatry the techniques of tissue sam- 
pling and cell culture that have been of great value 
in characterizing molecular abnormalities in nu- 
merous medical diseases” (192). Continued devel- 
opment of this line of research could reduce the 
use of animals in such investigations. 
In vertebra tes 
Few behavioral studies use invertebrates as sub- 
jects (139). As a consequence, relatively little is 
known about invertebrate behavior. In behavioral 
research, invertebrates offer a fertile testing 
ground for any theory that claims to be broadly 
based across the phyla of the animal kingdom (138). 
Certain groups of invertebrates are promising sub- 
jects for behavioral research. 
The brains of octopuses and squid approach 
those of vertebrates in relative size and complex- 
ity (178). Visual discrimination learning has been 
studied extensively in the octopus. Octopuses can 
discriminate between pairs of geometric shapes 
that differ with respect to vertical, horizontal, and 
oblique orientations. The octopus and squid show 
learning performance on a par with mammals on 
such tasks as detour problems, reversal learning, 
delayed response, and delayed reinforcement 
(178,218). 
Among all the invertebrates, the only species 
with a neuroanatomy and learning ability compa- 
rable to vertebrates are the octopus and squid. 
Practical problems in obtaining, transporting, and 
housing these marine species have always pre- 
cluded their widespread use as alternatives in be- 
havioral research (178). However, recent advances 
in the laboratory culture of octopuses make them 
promising research candidates, although provid- 
ing live food (e.g., shrimp) on a consistent basis 
