Question

1. Hormones can also influence an animal’s “motivation” to engage in a particular behavior.
   1. Discuss how an experimental study of “appetitive behavior” in male Japanese quail illustrates this concept. As part of your answer be sure to explain specifically how testosterone is involved.
   2. For the above example, describe in detail how the experiment was performed. Be sure to explain what control group was included in the study, and explain what that group was controlling “for” and why it was important to include.
2. 3. For the above example, if you were going to add another control group, what would it be, and why (i.e., what would that control group be “for”)?
   4. Explain the concept of a “positive control” and a “negative control” in the context of this experiment (note: the experiment presented in the lecture notes only really has one of those in it….the other would be something that could have been added to the experiment).
3. 5. What kind of experimental outcome in the treatment groups would have made having a negative control most important? Same question but for positive control?

Answer 1

a) Central testosterone aromatization is required for the activation of both appetitive (ASB) and consummatory (CSB) male sexual behavior in Japanese quail. There are two major clusters of aromatase immunoreactive (ARO-ir) cells in the rostral forebrain; these outline the nucleus preopticus medialis (POM) and the nucleus striae terminalis (BST)..Appetitive male sexual behavior was measured with the use of a learned social proximity procedure that quantified the time spent by a male in front of a window with a view of a female who was subsequently released into the cage, providing an opportunity for CSB...Testosterone potency can be changed locally via aromatization into 17β-estradiol which then activates estrogen receptors of the alpha and beta sub-types. the independent activation of either receptor activates different aspects of male sexual behavior in Japanese quail...the specificity of testosterone action on target genes transcription is related to the recruitment of specific steroid receptor coactivators... the specific down-regulation of the coactivators SRC-1 or SRC-2 in the medial preoptic nucleus by antisense techniques significantly inhibits steroid-dependent male-typical copulatory behavior and the underlying neuroplasticity.....that the interaction between several steroid metabolizing enzymes, steroid receptors and their coactivators plays a key role in the control of steroid-dependent male sexual behavior and the associated neuroplasticity in quail.

b) Method this Experiment  involved male Japanese quail.. the young birds were housed in groups in brooders..Sexually mature stimulus females used during the behavioral tests were purchased at the same dealer and were housed under the same conditions as the males.All male subjects were castrated under complete anesthesia..within 1 week after their arrival in the laboratory. The two testes were removed through a unilateral incision behind the last rib ..wo weeks later, approximately three-quarters of the birds received one SILASTIC implant..The rest of the subjects served as controls and were implanted with a similar capsule that was left empty..Throughout the experiment, birds were periodically weighed to the nearest gram, and the size of their cloacal gland was measured with calipers ...These data confirmed the efficacy of the testosterone replacement (the species-typical enlargement of the cloacal gland was regularly observed in all subjects) as well as the absence of adverse effects of the experimental treatments on the general health condition of the subjects (all birds slowly gained weight with time, as normally observed in this age range)..At the beginning of the test, one male was introduced into the main chamber and one stimulus female was placed in the adjacent smaller cage. The window between the two compartments was closed at that time. Birds were given 5 min to habituate to the new environment. The position of the male was then recorded continuously during the next 5 min period with the window still closed (pretest)...most of the testosterone-treated males acquired the social proximity response during these eight tests, whereas castrated control subjects were never observed to spent a significant amount of time in front of the window. ..Subjects in one of these groups received in the following days a bilateral electrolytic brain lesion, whereas the other testosterone-treated birds and the castrated controls were subjected to a sham operation.Cells within the second and third rostrocaudal subdivisions of the POM seem to be particularly important for the control of appetitive aspects of quail male sexual behavior

c) Instead of males quails we can put female quails also as a control to see how they behave ...because testosterone is also present in female but in very little amount so from this we can see how female quails behave when they put in front of thw window

d) Basically A positive control is a control group in an experiment that uses a treatment that is known to produce results and a A negative control is a control group in an experiment that uses a treatment that isn't expected to produce results....Positive control are the quails in which SILASTIC implant has been done and negative control are quails in which SILASTIC implant has not been done or implantation done by some other things which does not contain testosterone

e) Negative control does not show any effect of testosterone because it was not implanted ...and in positive control we can see a positive result of testosterone