Preterm birth is detrimental to the well-being of both the mother and the newborn. During normal gestation, the myometrium is maintained in a quiescent state by progesterone. As a steroid hormone, progesterone is thought to modify uterine and placental morphology by altering gene expression, but another direct mode of action has long been suspected.
View Article and Find Full Text PDFNatural scenes are composed of a wide range of edge angles and spatial frequencies, with a strong overrepresentation of vertical and horizontal edges. Correspondingly, many mammalian species are much better at discriminating these cardinal orientations compared to obliques. A potential reason for this increased performance could be an increased number of neurons in the visual cortex that are tuned to cardinal orientations, which is likely to be an adaptation to the natural scene statistics.
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