Plasticity of Brain Function

From The Parallax View, p. 209:

Our brain is a historical product, it develops in interaction with the environment, through human praxis. This development is not prescribed in advance by our genes; what genes do is precisely the opposite: they account for the structure of the brain, which is open to plasticity, so that some parts of it develop more if they are used more; if they are disabled, other parts can take over their function, and so on. What we are dealing with here is not only differentiation but trans-differentiation, “changing the difference.” Learning and memory play a key role in reinforcing or suspending synaptic links: neurons “remember” their stimulations, actively structure them, and so forth. Vulgar materialism and idealism join forces against this plasticity: idealism, to prove that the brain is just matter, a relay machine which has to be animated from the outside, not the site of activity; materialism, to sustain its mechanical determinist vision of reality. This explains the strange belief which, although it is now empirically refuted, persists: the brain, in contrast to other organs, does not grow and regenerate; its cells just gradually die out. This view ignores the fact that our mind does not only reflect the world, it is part of a transformative exchange with the world, it “reflects” the possibilities of transformation, it sees the world through possible “projects,” and this transformation is also self-transformation, this exchange also modifies the brain as the biological “site” of the mind.