Saturday, May 24, 2008
[from the final pages of The Fundamentals of Brain Development: integrating nature and nurture, Joan Stiles, Harvard UP 2008]
“The view of brain development presented here is dynamic, interactive, and adaptive. Complex signaling cascades [of produced cellular-environmental proteins] direct the formation and fate of cell populations, specify the migratory pathways and final destinations of new neurons, direct the formation of connections, and even signal cell death [e.g., for neural net pruning] in targeted populations [having overexuberant neuronal genesis]. The developmental process can adjust to contingencies and even to direct insult [i.e., injury] to brain structure. Yet there does not appear to be a blueprint, an executive, or even a homunculus [So it goes, Terence Deacon] directing the continuous changes in the complex array of elements, systems, and processes that emerge, expand, change, and sometimes just disappear across [a] period of development... .
-- 5:03 PM