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Cortical Expansion

26 Aug

So I stumbled across this abstract and picture a little while ago. Both come from similar patterns of cortical expansion during human development and evolution, a paper published at Yale earlier this year. The title basically sums up the idea, though I think some of the finer suggestions of why this happens are pretty neat.

Hill et al. notice that the newer portions of our brains (mainly, the giant cortex, which is responsible for our ‘higher’/more ‘human’ brain function, and is the most recent to be ‘tacked on’ as in Dr. Linden’s model) tend to develop considerably after birth, whereas the basic units responsible for survival–not so unique to humans–are already developed by the time we exit the womb. It’s interesting to think about how much is left to be shaped by our experience–and it seems that the equipment and allowance of extensive experience-based molding is a large chunk of what sets us apart.

Accidental Mind – Tidbit 2

19 Aug

Here’s a continuation of the memory discussion from Dr. Linden’s The Accidental Mind.

Throughout the course of the book, Dr. Linden stresses the fact that our brains were built by ‘tacking on’ new structures over the course of evolutionary history. As our brains became more and more complex, it was not due to a ‘wiping away’ of an old, less-complex brain and building a brand new one, but rather because new structures were simply lumped on top of the old ones and were forced to work together.

In addition, our emotionally-cued memories–which we retrieve actively, changing them every time we recall them–form the basis of the thought structure we use to perceive the world in the present.

So, Dr. Linden summed this up in a great snippet at the end of chapter five:

“Our memory, which is the substrate of our consciousness and individuality, is nothing more than the accidental product of a work-around solution to a set of early evolutionary constraints. Put another way, our very humanness is the product of accidental design, constrained by evolution.” (p. 144)

Accidental Mind – Tidbit 1

18 Aug

I’ve been reading The Accidental Mind by JHU neuroscience expert Dr. David Linden. So far, I’ve found his explanations illuminating… and I’ve chucked at his randomly-inserted quips involving Elvis, Richard Simmons, and everybody’s own version of an ‘Aunt Matilda’. I’ve decided to post some noteworthy excerpts here to give you all a taste, but you should really just go buy a copy. :)

From pg 108-109, a bit about why emotion is essential to our everyday thought processes:

“We need a signal to say, ‘This is an important memory. Write this down and underline it.’ That signal is emotion. (…) These are the building blocks that form logic, reasoning, social cognition, and decision making. These are the memories that confer your individuality. And that function, memory indexed by emotion, more than anything else, is what a brain is good for.”