Lordosis behavior
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Lordosis behavior, or Mammalian lordosis, is a sexual response during estrus in certain female mammals, such as mice and cats, that consists of a ventral arching of the spine. During lordosis, the spine curves so that the apex points in the ventral direction. That is, the convexity of the curve is on the side of the "belly" and the concavity of the curve is on the side of the back.
Lordosis aids in copulation, as it elevates the female genitals, so the male can more easily mate with the female.
In female mice during estrus, the hormone, estradiol (a hormone of the class of hormones known as estrogens), affects neurons in the ventromedial hypothalamus, the periaqueductal gray and other areas of the brain. Sexual stimuli trigger activity in a number of brain areas, including the ventromedial hypothalamus, which sends impulses down axons synapsing with neurons in the periaqueductal gray. These convey an impulse to neurons in the medullary reticular formation which project down the reticulospinal tract and synapse with afferent neurons in the spinal cord (L1-L6) which contract muscles along the spine to exhibit the lordosis posture. Since these afferent neurons are also part of a reflex arc, lordosis can also be triggered reflexively.
