By Catherine A. Sanderson, Amherst College
Starting in the early 1990s, breakthroughs in technology have allowed us to see how people’s brains respond in different situations and to different stimuli. Findings in neuroscience have revealed that physical exercise stimulates the brain in ways that improve cognitive skills, that people who procrastinate differ in particular parts of the brain compared to those who don’t, and that psychotherapy can literally change someone’s brain.
Brain Injuries and Impairments
Some of our earliest knowledge about how different parts of the brain have different functions came from studying how people with different brain injuries experience distinct types of impairments.
In 1848, a young railroad foreman named Phineas Gage suffered a tragic accident while packing explosive into a hole when the powder detonated sending a metal rod directly into his face. The rod entered his left check, tore through his brain, exited the back of his skull, and then landed 80 feet away. Gage survived this severe injury and was able to walk to a nearby cart so that he could be taken to receive medical treatment. He remained conscious the entire time and was even able to speak.
After Gage’s recovery, he tried to return to work, but was soon fired. Reports at the time described him as a changed man after the accident, shifting from a previously friendly, efficient, and capable worker to one who was impulsive and unreliable. As one of his friends described, “Gage was no longer Gage”.
Although it’s clear that Gage’s personality changed considerably following the accident, more recent examinations of his life suggest he was less severely injured than is often described. He spent many years driving stagecoaches, which required relatively high-level motor, cognitive, and interpersonal skills.
But this case remains an important one in the field of psychology because it was the first to suggest that specific areas of the brain control certain functions. This is what we now call the localization of brain function. And modern techniques provide even more insight into how different parts of the brain function.
This article comes directly from content in the video series Introduction to Psychology. Watch it now, on Wondrium.
Electroencephalography or EEG
One such approach, the electroencephalography or EEG, involves placing electrodes on a person’s head and then measuring the electrical activity produced by the brain’s neurons during different tasks. An EEG can measure changes in brainwave patterns during different stages of sleep, or while a person is reading, writing, or speaking.
Studies using EEG reveal that brain activity differs when people view members of different groups—men versus women, black people versus white people. This type of categorization happens automatically, with little or no conscious awareness or control.
It can also be used to measure patterns of brain activity while someone is moving around, which can be especially useful when studying children.
Stimulation and Brain Development
In 2018, researchers at the Institute for Learning and Brain Sciences at the University of Washington placed caps containing EEG electrodes on two-month-old babies to see how their brains responded when different parts of their bodies were gently tapped. When the baby’s left hand or foot was touched, the researchers saw activity in the right side of the brain.
This study shows that stimulation from the environment—when parents touch their babies’ hands or feet—actually helps develop that particular part of the brain. These same parts of the brain were also active when babies kicked their feet against a mobile or opened or closed their hands.
MRI and fMRI
However, the brain’s structure and localized activity are revealed much better with Magnetic Resonance Imaging, or MRI, which takes a picture of the brain’s anatomy. MRI later led to fMRI, or functional MRI, which investigates which part of the brain is handling specific functions.
An fMRI measures small changes in blood flow that occur while the brain is performing a particular type of task, such as reading or moving. These techniques can be used to determine what part of the brain responds to some task or stimulus, such as seeing a picture of a spider or while listening to music. They can also be used to evaluate whether multiple parts of the brain are firing, or ‘lighting up’, in response to the same stimulus.
Studying the Patterns of Brain Activity
One fascinating study using fMRI data examined patterns of brain activity in young kids as they looked at math equations where the answer shown might be correct or not, such as 7 plus 2 equals 9 or 8 minus 2 equals 5.
Children who were high in math anxiety showed less activity in a particular part of the brain that’s responsible for mathematical reasoning, showing the part of the brain that should have been evaluating the answer wasn’t really engaging. Meanwhile, another part of the brain, the amygdala, which processes negative emotions, was very active.
Imagine being able to identify kids at risk of math phobia early on, which could help us take steps to reduce such anxiety.
Common Questions about Understanding the Patterns of Activity of the Human Brain
The electroencephalography or EEG involves placing electrodes on a person’s head and then measuring the electrical activity produced by the brain’s neurons during different tasks. An EEG can measure changes in brainwave patterns during different stages of sleep, or while a person is reading, writing, or speaking.
Magnetic Resonance Imaging, or MRI, reveals the brain’s structure and localized activity much better than EEG. It takes a picture of the brain’s anatomy.
The fMRI, or functional MRI, investigates which part of the brain is handling specific functions. An fMRI measures small changes in blood flow that occur while the brain is performing a particular type of task, such as reading or moving.