Figure 6.

The mechanisms of motivation and satiety are complementary and mediate the appetitiveness or aversivity of stimuli. For example, a female rat may perceive a male as a positive stimulus. His odor triggers sexual motivation through the vomeronasal organ (VNO). The male produces positive feedback via tactile stimulation of the flanks and perineum. The valence of the odor and genital stimulation is processed in the medial amygdala, piriform cortex, and NAc, structures that project to the middle preoptic area (mPOA) and the anterior (MAH) and ventromedial hypothalamus (VMH), where appetitive sexual states are perceived. The information is projected to the midbrain (PAG), where the superior motor neurons convey it to the lumbosacral segments. The motor response involves centers of the lateral vestibular nucleus (LVSN) and reticular formation (RF). These axons reach the spinal cord through the lateral spinal vestibule (VET) and reticulospinal tract (RET) where, in conjunction with signals from tactile receptors, the contraction of the lateral longissimus and transverse spinal muscles are generated to produce lordosis [159]. HT: hypothalamus. After copulation, during satiety, the same olfactory and genital stimuli reduce their incentive value, and females will no longer experience reward. If they cannot get away, then copulation can evoke aversion.