The earliest ways of peering into the brains of people was invasive, and sometimes, fatal. Consequently, most subjects were those who were mentally disabled, those who had mental illnesses. Therefore, we now know more about dysfunction than we do function. However, this isn’t a bad thing, considering that it’s through dysfunction that we can better understand how a healthy brain works.
There was an 18oo’s experimenter, Angelo Mosso. Mosso had the chance of encountering a peasant named Bertino. Now, Bertino suffered a head injury several years prior to meeting Mosso. The injury was severe enough that it destroyed his frontal bone of his skull, which cover the frontal lobe. The frontal lobe is for reasoning, decision-making, planning, all the executive functions, and personality. What was most interesting to Mosso, however, was the fact that because Bertino had this bone injury, his frontal lobes were now covered not by bone, but by fibrous tissue. This tissue acted as a window through which Mosso could see Bertino’s brain pulsating.
I’m sure if you saw a pulsating brain, you’d investigate further. And that’s exactly what Mosso did.
So one day, Mosso noticed that tere were changing in the pulsation magnitude: whenever the church bells rung at noon, the pulsating increased. So what does Mosso do?
He asks Bertino a question: does the ringing of the church bells remind you of your obligation to silently recite the Ave Maria?
To which Bertino responds: Yes.
And as Bertino responded, the pulsations increased once more.
So of course Mosso is ultra-curious now. He asks Bertino some math questions, like multiply this by that. Whenever Mosso asked a question, the pulsations increased. Whenever Bertino answered a question, there was another pulse magnitude increase.
If you made these observations, what would you hypothesize was going on?
This was Mosso’ hypothesis, which proved to be correct: an increase in blood flow to the brain could provide a measure, albeit indirect, of brain function during a specific activity.
Image is from Wikipedia, Angelo Mosso article.