Mechanisms of brain plasticity: from normal brain function to pathology.

Since this list of mechanisms covers much of what we know about how brain cells operate, one might object to using such a broad brush in characterizing a purportedly special feature of brain function--"plasticity." But that is really just the point. If a significant aspect of brain function is "plasticity," as I believe to be the case, then all (or at least most) brain mechanisms are likely to be involved in "plastic" processes. Indeed, we have identified very few "special" mechanisms associated with plasticity. Certainly, the factors that appear to be involved in epileptic pathologies are almost all old friends from the plasticity literature. It is this critical interrelationship between plasticity and pathology that was so important in Frank Morrell's work, a concept he advanced at a time when our understanding of these mechanisms was far less sophisticated than it is now. The influence of this idea is now pervasive in the neuroscience field, so much so that it is hard to imagine why there was so much resistance to these hypotheses when first advanced by Morrell. It is this general concept of plasticity-pathology relationship that will survive as the most influential legacy of Frank Morrell.