to rodents during perinatal life, as the mesocortical dopaminergic pathway is developing, dopaminergic innervation of the mPFC increases. As a result, TH-ir fiber density also increases. Interestingly, this increase in TH-ir fibers and dopaminergic activity is also linked to impaired cognitive flexibility with increased perseveration later on in life. In combination, these findings suggest that PR expression during early development impact later cognitive functioning in rodents. Furthermore, it appears as though abnormal levels of PR activity during this critical period of mesocortical dopaminergic pathway development may have profound effects on specific behavioral neural circuits involved in the formation of later complex cognitive behavior. Ligands Agonists Endogenous progestogens (e.g., progesterone) Synthetic progestogens (e.g., norethisterone, levonorgestrel, medroxyprogesterone acetate, megestrol acetate, dydrogesterone, drospirenone) Mixed Selective progesterone receptor modulators (e.g., ulipristal acetate, telapristone acetate, vilaprisan, asoprisnil, asoprisnil ecamate) Antagonists Antiprogestogens (e.g., mifepristone, aglepristone, onapristone, lonaprisan, lilopristone, toripristone) Interactions Progesterone receptor has been shown to interact with: KLF9, Nuclear receptor co-repressor 2, and UBE3A. See also Membrane progesterone receptor Selective progesterone receptor modulator Phytoprogestogen References Further reading External links Intracellular receptors Progestogens Transcription factors