Intra-uterine levels of oestrogens affect foetal brain development, particularly cerebral lateralization
1985 Study Abstract
The authors present a set of hypotheses about the biologic mechanisms of lateralization, ie, the processes which lead to an asymmetrical nervous system.
Biological Mechanisms, Associations, and Pathology: I. A Hypothesis and a Program for Research, The Jama Network, doi:10.1001/archneur.1985.04060050026008, May 1985.
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It would have been difficult even 20 years ago to formulate such a theory in the face of the prevalent belief that cerebral dominance lacked an anatomic correlate. It is proposed that cerebral dominance is based in most instances on asymmetries of structure.
Although genetic factors are important we will lay stress on several factors that, in the course of development, both prenatal and postnatal, modify the direction and extent of these structural differences. Special attention will be directed to the intra-uterine environment as a determinant of the pattern of asymmetries, and in particular sex hormones, eg, testosterone or related factors.
We will discuss the associations of anamalous cerebral dominance which include not only developmental disorders such as dylexia and certain talents but also alterations in many bodily systems, including the immune system, the skin, and the skeleton. It is proposed that the same influences that modify structural asymmetry in the brain also modify other systems.