BBB - Tools for Examining Brain Structure and Function Lesson

Learning Targets:

• Recount historic and contemporary research strategies and technologies that support research. 
• Identify the contributions of key researchers to the development of tools for examining the brain. 

AP psychology course and exam description, effective fall 2020. (n.d.). https://apcentral.collegeboard.org/media/pdf/ap-psychology-course-and-exam-description.pdf

Tools for Examining Brain Structure and Function

The Brain

Our brain is the single most important structure in our bodies and is responsible for controlling human thought, emotion, and behavior. It weighs approximately three pounds (2% of our total body weight), uses 20% of our oxygen while at rest, and is made up of billions of neurons and glial cells. These neurons and glial cells create an integrated system of neural pathways that is so important that it is encased in bone.

Even with all this protection our brains sometimes do become damaged. However, damage does not always necessarily mean a loss of function. The brain is what we call plastic, meaning that if one area becomes damaged then other areas of the brain will take over by rerouting themselves to the damaged area. However, the older we become, the less plastic our brains are.

The brain is difficult to study due to its protection and its complexity, but humans have always tried. Old methods for studying the brain include creating case studies of those with damaged brains and those who are incredibly talented. Case studies have provided us with much information about the workings of the brain but remember what we learned about the generalizability of case studies... there isn't much. Today brain research does not seek to tell you everything you ever suspected or wanted to know but provides you with some basic information.

The goals of studying the brain include:

1. to familiarize you with its basic organization
2. to provide you with a general sense of how the brain works

 

Ways to Study the Brain: Accidents and Lesions

Accidents

Sometimes the brain becomes damaged, providing us with a unique opportunity to study the brain. The most famous case study occurred on September 13, 1848, and involved a man named Phineas Gage. Phineas Gage was a mild-mannered railroad worker who was involved in an accident on the job. A four-foot, thirteen-pound iron pole shot through his head just under his left eye and came out the top. Miraculously, Phineas fully physically recovered. However, his personality changed forever.

Dr. John Harlow attended Phineas right after the accident and during recovery. He made note that prior to the accident Phineas had been described as friendly, competent, and respectful. Afterward, he was described as stubborn, ill-tempered, and profane. Based on this case study, the idea that our frontal lobes were responsible for socio-emotional behavior, our reasoning ability, the ability to think and plan, and decision-making came to fruition.

Lesions and Lobotomy

A lesion is the destruction or removal of part of the brain. Researchers study the effects of destroying parts of the brain on behavior and functioning. When parts of the brain are altered, destroyed, or removed the effects are observed, providing us with useful information on what different brain parts do.

During the 1900s doctors commonly would perform frontal lobotomies (A frontal lobotomy involves cutting the connections to and from the prefrontal cortex, resulting in major personality changes.) on mental patients to change their personalities and alleviate their illness. This procedure was commonly performed on patients suffering from schizophrenia, depression, anxiety, and nuisance behavior. Unfortunately, these procedures were often done under less-than-ideal conditions outside of an operating room, with no anesthesia, and without the service of a surgeon.

 

Ways to Study the Brain: Brain Scans

Brain scans are a less invasive way to study the brain. No longer are researchers waiting for accidents to happen or going out and damaging or lesioning the brain. Brain scans electrically, chemically, and magnetically stimulate parts of the brain and record the effects.

Complete the Types of Brain Scans activity below:

There are some limitations to think about when using brain scans. The limited amount of equipment available and the excessive cost are other factors. Additionally, because of the small number of scans produced it is difficult to generalize. Human behavior is so complex and brain scans only provide a simple snapshot of behavior.

When we do use brain scans it is important to read the description and results carefully and be sure that you understand what is being measured. Providing a comparison scan is also important so that you know what you a looking for and how it compares to what is considered "normal".

 

Roger Sperry

 

Roger Sperry was an American neuropsychologist who made significant contributions to our understanding of the brain and its functions. He is best known for his research on split-brain patients, which showed that the two hemispheres of the brain are specialized for different functions, a phenomenon known as brain lateralization. Through his experiments, Sperry demonstrated that the left hemisphere of the brain is specialized for language processing and analytical reasoning, while the right hemisphere is specialized for spatial perception, visual imagery, and holistic thinking. His work had important implications for our understanding of brain plasticity and continues to influence the field of neuropsychology today.

 

 

 

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