Brain

[Guest guest]

From The Birth of the Mind: How a Tiny Number of Genes Creates the

Complexities of Human Thought by Gary Marcus:

 

" It is popular in some quarters to claim that the human brain is

largely unstructured at birth; it is tempting to believe that our

minds float free of our genomes. But such beliefs are completely at

odds with everything that scientists have learned in molecular

biology over the last decade. Rather than leaving everything to

chance or the vicissitudes of experience, nature has taken everything

it has developed for growing the body and put it towards the problem

of growing the brain. From cell division to cell differentiation,

every process that is used in the development of the body is also

used in the development of the brain. Genes do for the brain the same

things as they do for the rest of the body: they guide the fates of

cells by guiding the production of proteins within those cells. The

one thing that is truly special about the development of the brain—

the physical basis of the mind—is its " wiring " , the critical

connections between neurons, but even there, as we will see in the

next chapter, genes play a critical role.

" This idea that the brain might be assembled in much the same way as

the rest of the body—on the basis of the action of thousands of

autonomous but interacting genes (shaped by natural selection)—is an

anathema to our deeply held feeling that our minds are special,

somehow separate from the material world. Yet at the same time, it is

a continuation, perhaps the culmination, of a long trend, a growing-

up for the human species that for too long has overestimated its own

centrality in the universe. Copernicus showed us that our planet is

not the center of the universe. William Harvey showed that our heart

is a mechanical pump. John Dalton and the 19th century chemists

showed that our bodies are, like all other matter, made up of atoms.

Watson and Crick showed us how genes emerged from chains of carbon,

hydrogen, oxygen, nitrogen and phosphorus. In the 1990s, the Decade

of the Brain, cognitive neuroscientists showed that our minds are the

product of our brains. Early returns from this century are showing

that the mechanisms that build our brains are just a special case of

the mechanisms that build the rest of our body. The initial structure

of the mind, like the initial structure of the rest of the body, is a

product of our genes. "