To extend my comment, there are dozens of citations for the 1970's era paper that assert that the "brain growth spurt" extends from the third trimester to the f

To extend my comment, there are dozens of citations for the 1970's era paper that assert that the "brain growth spurt" extends from the third trimester to the first few years of life. It is then equated with synaptogenesis or "peak synaptogenesis", even though this association may be unclear. The papers then further equate peak synaptogenesis with the period of vulnerability to anesthesia. Many then postulate mechanisms for anesthesia-related neurotoxicity in infants related to mechanisms of synaptogenesis. Not being an expert in the field, I can't refute this argument, but I do find the links between these phenomena to be rather shaky, especially when based on a throwaway reference to a decades old paper.