Motivational Systems in Rats and Monkeys:
Are They Homologous
Methods Page 3


Title/Abstract page

-

Introduction
Page 1

-

Methods
Pages 2 - 3

-

Results
Pages 4 - 5 - 6

-

Discussion
Pages 7 - 8 - 9 - 10

-

References
Page 11

-

Figures
Figures 1 - 2 - 3

(Continued from previous page)

In order to make the data analysis of the rat experiment more similar to that of the monkey experiment, several aspects of the previously published analysis [Lehman and Adams, 1977] were reanalyzed. 1) The data on vocalization, ultrasound, and screaming were correlated with specific acts and postures, which had not been done in the previous study. 2) Running away was separated from walking away from the opponent. 3) The dyadic sequences within the animal consisting of repetitions of the same behavior were computed, unlike in the published study, and significance values were obtained. The following behaviors were repeated at rates that were nonrandom: in the resident rat, self-grooming of the side, allogrooming, and offensive sideways posture; in the intruder rat, crouching, upright posture, and defensive sideways posture.

For purposes of comparison, some changes were also necessary in the analysis of the data from the stumptail macaques. 1) Data from confrontations between two dominant animals were omitted, because comparable confrontations were not tested with rats. 2) Data from minutes 11-20 of the longer tests were omitted from total frequency data and only data for the first 10 min were used, because data from rats were taken from only 10 min of testing.

Certain differences in the methodologies for the rat and monkey studies should be noted, since they might have a bearing upon differences in results. 1) While the dominant rat was the resident of his test cage, the dominant monkeys were tested in a standard test cage that was not the home cage. The test cage for monkeys was relatively large and too expensive to be duplicated. 2) While separate rats were used for each test, only six monkeys were available; in order to achieve a large number of behavioral episodes, multiple tests were required for each individual. 3) Because most agonistic and sexual behaviors occurred in the first 5 min of testing, many of the monkey tests were not carried out for the full 10 min, while all of the rat tests lasted 10 min. 4) The size of the test cage was proportionally larger for the monkeys.

previous page
home page
next page