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I. Introduction and Background
Page 1
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II. The Static Model
Pages 2 - 3
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III. The Dynamic Model
Pages 4 - 5 - 6
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IV. Future Work
Page 7
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Figures 1-6
Pages 8 - 9 - 10 - 11 - 12 - 13
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References
Page 14
Although this is the first publication of a dynamic model of the offense motivational system, static models have been published previously. The basic system, derived from comparative analysis of behavioral reports of various muroid rodents was published by Adams (1980). Other papers have described its neural substrate (Adams, 1979a), effects of hormones (Adams, 1983), and sites of action of learning and imprinting (Adams, 1979b). Extrapolations from muroid rodents to primates have also been published (Adams, 1981; Adams and Schoel, 1982).
Before describing its dynamic qualities, it is necessary to describe the static qualities of the offense motivational system, as it is illustrated in Figure 2. This system is the same as the one that has been described in the above-listed publications, but has been modified in a number of ways, to be considered in further detail.
The offense motivational system, like other motivational systems is divided into four types of neural structures: I) motivational mechanism; 2) motivating stimulus analyzers; 3) motor patterning mechanisms; and 4) releasing and directing stimulus analyzers.
At the center of the system is the motivational mechanism of offense. This is a pool of neurons (its location in the brain has not yet been determined) whose activity determines the motivational state of the animal. To put it in human terms, it determines how "angry" the animal is. Its activation affects both the readiness to exhibit the motor patterns of offense and the readiness of the sensory analyzers pertinent to the system. It should be noted that effects of motivation upon sensory analyzers were postulated in Adams (1979a) but have not been illustrated in previous publications. The existence of such effects has been shown for other motivational systems by Flynn et a1 (1971), but they have not been demonstrated in offense.
The offense motivational mechanism interacts with other motivational mechanisms. It is inhibited by the defense/submission (fear) motivational mechanism, as shown by Mink and Adams (1981). In previous publications the submission motivational mechanism has sometimes been described as a combination of a defense motivational mechanism with a conspecific modulator (Adams, 1979a), although it may be better to distinguish it as a separate system from defense (Adams, 1980). It is also facilitated by a competitive fighting synthesizer which operates under conditions of hunger and thirst, but this interaction will not be considered in detail in the present paper.
Motor patterning mechanisms are illustrated for five of the most common and obvious acts and postures of muroid rodents during fighting behavior; approach, offensive upright posture, offensive sideways posture, full aggressive posture, and bite-and-kick attack. These acts and postures have been described by Grant and Mackintosh (1963). Their neural locations have not yet been determined. Four other motor patterning mechanisms have not been illustrated in order to conserve space in the figure: offense pheromone production, teeth-chattering, tail-rattling, and piloerection. The five motor patterns that are illustrated do not occur under normal conditions unless there are simultaneous excitatory inputs from the motivational mechanism and the appropriate releasing stimulus analyzer into the motor patterning mechanism.
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