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The Neuron- Up Close and Personal

The Question of Intelligence
  1. absolute size
  2. brain/body size
  3. cortical folding
  4. neocortex
  5. gray matter/nerve cells
  6. specific brain structures




What's all this fuss about the neocortex?

This idea of cortical folding leads us to consider the significance of the neocortex in general. First of all, what is neocortex??? Neocortex is the structure in the brain that differentiates mammals from other vertebrates and it is assumed that the neocortex is responsible for the evolution of intelligence.

Is there a relationship between the amount of neocortex and brain size? Relevant data have been provided by a number of authors (Macphail, Stephen, Harman) that there is within different mammalian orders a good correlation between brain size and both neocortical volume and neocortical surface (see Figure 7.3 and 7.4, Macphail, p. 248). There are some slight differences, however, in that rodents have less relative neocortex than primates, carnivores, and ungulates, and that some types of opossums have even less than rodents.

What is the significance of these statements? First, it seems that man possesses no more neocortex than would be expected according to brain size. Second, although primates generally have more neocortex than some other mammals, they clearly are not unique in their neocorticalization.

One may expect, knowing the "role" (see above, or see glossary) of neocortex, that man and primates show so little superiority in terms of amounts of neocortex. Yet, what happens when data about neocortex is collected or analyzed slightly differently? Let's look at another method of research and see if there is an effect on outcomes and conclusions about neocortical significance . . .

Ok, continue discussion of the neocortex

I want to go back to brain and body size

Huh? Can we start over?