Brain Function: An Introduction

The Frontal Lobe, the Amygdala and the Prefrontal Cortex

Numerous studies have shown that there are correlations found between brain function and violent behaviour. In order to fully understand these studies, it’s important to have a general understanding of some of the functions of these parts of the brain. The brain is labelled as having different “lobes”.

One important function of the frontal lobe is to regulate our impulsive decision making. It also lets us make long-term decision making in the sense that it allows us to foresee and imagine possible implications for our actions. It kind of acts like a “break” on our impulsive behaviour. So when you get really angry at your teacher and you want to curse but don’t because you know that it will get you in trouble, you have your frontal lobe to thank. The impulsivity of young children can be explained through their still-developing frontal lobes.

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Here we can see how the brain has different “lobes”. In this course we will learn a lot about the frontal and prefrontal area (above the forehead).

When learning about the brain, it’s always important to remember that brain function is complex and to avoid the allure of simplifying down to claims like “our frontal lobes control our behaviour.” Human behaviour is far too complex, as is the brain, for both to be boiled down to such a simple statement. A more accurate statement would be “our frontal lobes are associated with self-control.” The phrase “associated with” is a useful one when discussing the brain because it suggests a correlation between brain function and behaviour without oversimplifying the relationship.

The prefrontal cortex is the area at the very front of the brain. The cortex refers to the dense outer layer of the brain where 90% of the brain’s neurons are. (Here’s a video if you want to learn more).

One of the first and most famous studies of a man who had severe damage to his frontal lobe was that of Phineas Gage. Gage was a railroad worker who was putting dynamite into rocks while working with a team to lay tracks. As he used a six-foot bar to pound the dynamite powder into the rocks it ignited, essentially making the long steel pole a bullet that fired up through his left eye, through his skull and landed about 50ft away. Gage survived and was even conscious while he rode on the ox cart to the nearest town. As a result of the incident, Gage’s behaviour seemed to change as he went from being a rather mild-mannered man to “no longer Gage” as his friends said. This was in 1948 and Harow, the Doctor who treated Gage, made a few observations about the change in Gage’s behaviour that has made him one of the first and most famous cases that links brain damage to personality change.

Since Phineas Gage there have been heaps of studies into the correlations between brain damage, brain function and behaviour. With modern imaging technology (MRI’s, fMRI’s, PETs, etc.) researchers can investigate further connections between brain function and behaviour.

So based on this, would you think that people who act violently have normal functioning, high functioning or low functioning frontal lobes?

The biological correlates of criminal behaviour has been the subject of numerous studies. Time and again research has shown that there are common brain functioning and activity differences in criminals when compared with healthy and normal controls.

When researching these correlates it’s important to remember their general function, but not to oversimplify the biological processes underpinning human behaviour.

Summary

  • Our brain has different parts
  • Research can show that these parts have different functions

This video provides a good introduction to understanding the brain and the nervous system.