Round The Table - Discuss

Tall order! (Or perhaps I should say 'Grande' or 'Venti'? Oh, pity my poor Pavlovian brain!). So we ask, what could constitute a common thread connecting all these topics? Where would I start?

Well, my choice du jour is: "If you want to understand something, break it!".

Now, what do I mean by this? In the sciences of the artificial, say engineering, we tend to follow a design -> build -> test -> refine cycle. Biology is expected to enter this cycle within the next decade or so (not easy to 'build' life!), but until recently, the approach has been to understand something by 'breaking' an existing biological 'object' - bacteria, viruses, plants, animals.

Here is an example:

Say you have two telephones (the old kind, imagine those beautiful black bakelite beasts on grandpa's table). You are an alien, making a stopover on earth, you have no idea what the device does. And then suddenly you notice that the device 'rings' sometimes. So you take a screwdriver and carefully take the top off the base. Then, you carefully cut a wire, but only on one of the phones. Then you watch, wait and see what happens. Hey presto, you are one lean, mean, science-machine! You notice that while the 'uncut' phone continues to ring occasionally, you record in your alien lab-notebook that the phone with the cut wire never rings. So you suspect that the wire you cut may have something to do with the 'ring'. Then you patch up that wire and cut somewhere else ... and continue, slowly getting an idea of what it is that a 'telephone' does.

You broke it, to understand a little bit! Iterative cycles of this can build a pretty picture of the machinery & its function. Biologists do the same thing in at least two simple ways:
(1) Natural 'break it': Disease, accident.
(2) Deliberate 'break it': artificially constructed genetic mutations.

All the topics mentioned above by Uttara can be addressed using this framework!
More later.

 

Speaking of 'slices of brain' ....

We move on, to connect the ‘break it’ approach to the human brain. Here the 'breaking' is a brain injury caused by an explosives accident. This is one of the most famous stories in the history of neuroscience.

Our story dates from 1848, when Phineas Gage, a 25 year old railroad worker, was involved in an accident that sent a steel railroad pin crashing through the underside of his chin, through his brain, sticking out the top of his skull. Amazingly, Phineas not only survived this, but was able to speak to his physician, who surgically removed the pin. Phineas recovered – but in a way that constitutes a dramatic episode in the history of science.

His friends noticed that while Phineas appeared healthy, Gage ‘was no longer Gage’. His behavior was dramatically altered – he became restless, irritable, prone to anger, incapable of rational decision-making. He went from an admirable young man to a ne'er do well in an instant. He was fired (he had been a prized employee) & ended up a jobless, homeless wanderer. You can read all about it here or in the countless re-tellings of this story on the web.

Even at the time of Gage’s injury, we already knew that there was a neural basis for ‘physical’ functions such as speech, perception and movement. However, there was no framework for higher brain functions: rationality, socially appropriate behavior, planning – all generally grouped under the rubric of “behavioral exceutive functions” or, more dramatically, “moral” behavior. Twenty years after the accident, John Harlow was the first to propose that perhaps those very areas of the frontal lobes damaged in the accident were the ones that accounted for our “rational” mind. His work had no impact. Science was not ready for his dramatic insight.

We then fast-forward to 1994, when Antonio Damasio & his crew used tomographic reconstruction to scan Phineas Gage’s skull, which had been preserved and can still be viewed at the Warren Anatomical Museum at Harvard. Using this, they were able to estimate which regions of the brain had been damaged by the injury & thus connect those areas of the frontal lobe to the higher executive functions of the brain. John Harlow was vindicated (at least somewhat – there is still technical controversy about details of interpretation, but the basics are sound). The first page and a half of the paper are non-technical & worth reading! Here, is a picture showing the trajectory of the projectile through Phineas Gage’s brain (from that paper).

 

Corrections:

(1) The Damasio paper is actually here.
Sorry for the wrong URL in previous post.

(2) I should have said "underside of his cheek", not "chin". Sorry, I was writing from memory!

(3) By the way, John Harlow was the original physician who treated Gage after the accident.

 

Fascinating! Brain and Spinal cord...two amazing parts of our anatomy. Even a little hurt, damage, or injury to these two can alter one's life so drastically.

Nice info on Phineas Gage Demasio Soks, vaguely remember reading or hearing about this incident.

As to breaking things to understand, I'd rather read here, have simply no interest to sit on a pile of garbage, which is what it will be by the time I'm done!

L, Kamla

 

Hi Uttara and Soks
Thanks a ton for the extnsive information on our brain. I read the articles and was going wow!
What an amazing puzzle our brain is; and yes, Uttara, you are right when you marvel, "How on earth, or blistering zooming comet should I say (in view of the panspermia theory of origin of life) did we evolve into these biological complex entities."

Simply amazing!

 

Hmmm more about brain!!!

Check this site about space explorations! I found it interesting and learned lot of facts!

Cosmoquest Forum