Baby’s brains begin as a collection of cells inside a mother’s womb. They separate out from other cells destined for other purposes and begin forming the nervous systems. Both the internal instructions of DNA and the external influences of neighboring cells ultimately combine to shape the future brain. Where the cells finally reside in the brain and how they interact with synapses and axons (the connections and the wiring of the nerves) determine how well it functions as we grow up.
Only with the development of recent MRI methods, have scientists begun to attempt a mapping of a developing fetus’s brain. With these new means of peering into baby’s brains at the earliest stages of growth, scientists are beginning to grasp how different influences shape the very anatomy of the future brain. From there, a few of the known factors have revealed their mechanisms of action.
As the brain depends on first a multitude of connections being made before pruning the unnecessary connections, factors that hinder this process change later functionality. Using functional MRI’s of infants after birth indicated an already present connectome, or pre-wired connectivity which could respond to various stimuli in different ways. As prenatal studies came out, brain wiring has been recognized as increasingly integrated during development.
Studies of prenatal drug exposure, a major public health concern, have begun to uncover how cocaine and marijuana affect the fetal brain. Structural changes were seen in areas of the brain which were related to memory, emotions, and reward systems. For marijuana, unsurprisingly, areas of the brain with higher levels of certain cannabinoid receptors were disrupted. In all these cases, unexposed fetal brains did not show these changes.
Studies of maternal mental health have also been revealing. The presence of depression changed connectivity between limbic system (emotions) and the amygdala (memory). In that study use of SSRI’s (Serotonin Reuptake Inhibitors) were not reported, but in another SSRI usage was associated with changes in brain white matter. In yet another study, SSRI usage correlated with EEG changes even after the early withdrawal period for the infant. Medicine needs much more research in these areas to understand the degree to which maternal antidepressants affect infant brain development.
For more in-depth reading, the article LINK can be found HERE. We are just scratching the surface of this field. With continued study, we can hopefully learn what factors play the largest role in brain development. With that we can learn how to optimize baby brains by building them with the best materials and avoiding the interfering factors.