Hypothetical neural circuitry that organizes and activates the agonistic behaviors of muroid rodents. Observed or recorded acts and postures, vocalizations, and hormone or pheromone secretions are produced by the motor patterning mechanisms (center right). Stimuli are of two types: Motivating stimuli that are processed by sensory analyzers that project to motivational mechanisms (left); releasing and directing stimuli that are processed by sensory analyzers that project to motor patterning mechanisms (right). <, facilitative effects; •, inhibitory effects; unbroken line, projections that are present in all or most species of muroid rodents: broken line, projections present in only some species. Several sensory analyzers are operational in only one sex, requiring activation by gonadal hormones, indicated by male or female symbols. Note added in 2002: Several aspects of this figure were not confirmed in later studies and hence the figure needs some revisions as seen in the Figure 1 in the Brain Mechanisms introduction. In particular, our study of patrol marking published in 1984 (below) failed to confirm any inhibitory pathway from a sensory analyzer to the patrol/marking motivational system, and it failed to confirm the existence of a motor patterning mechanism for facial gland secretion. Also, our 1994 study on competitive and territorial fighting made it necessary to interpose synthesizers between the sensory analyzers and the offense motivational mechanism. Lee, S.H., Mitchell, J., and Adams, D.B. (1984), An Empirical Study of the Structure of the Patrol/Marking Motivational System in the Rat. Physiology and Behavior, 32: 565-573. Adams, D.B., Cowan, C.W., Marshall, M.E., and Stark, J. (1994) Competitive and Territorial fighting: Two Types of Offense in the Rat, Physiology and Behavior, 55: 247-254.