Early Methods

• Case studies were one of the earliest methods to study brain damage, injury, and illness

• It would be unethical to artificially recreate these situations, however

• We can gather important information from the changes in an individual’s behavior and mental processes

  • This knowledge can possibly be applies or compared to other case studies/groups

Henry Molaison

• Molaison had severe epilepsy

• In 1953, a surgeon removed the hippocampus, the origin of the seizures

• At 27 years old, he lost the ability to form new memories

  • He did still have memories from before the surgery

• Molaison was referred to neuroscientists Wilder Penfield and Brenda Milner

  • They studied Molaison extensively throughout the rest of his life

  • They determined that the function of the hippocampus was forming and storing new long-term memories

• Molaison never regained the ability to form new memories

Louis Victor Leborgne

• In 1861, at the age of 30, he suffered a stroke

• When he entered the hospital, all he could say was “tan”

  • He could still use the term with inflection and gestures to communicate

  • The right side of his body became impaired

• His physician, Pierre Paul Broca, studied his behaviors extensively as well as his brain

  • Leborgne agreed to have it donated when he died, which happened when he was 51

• Broca’s research gave us our understanding of Broca’s Area

  • The region of the brain responsible for producing speech and choosing words

  • We now know that Leborgne suffered from Broca’s aphasia

    • The inability to produce speech and select words

• Tan’s brain is now on display at the Dupuytren Museum of Paris

Phineas Gage

• Gage was a railroad worker in Vermont

  • While tamping down gunpower, an explosion occurred

  • The tamping iron, a large metal rod, was shot through his head at extraordinary speeds and temperatures

    • It is thought that the rod was so hot it cauterized the wound on contact, saving Gage from bleeding out

• Gage remained conscious and is said to have walked part of the way to the doctor

• He suffered damage to his prefrontal cortex

  • This impaired his judgement

  • Emotion regulation

  • And planning

• He was “no longer Gage” according to accounts from family and friends

Split-Brain

• A split-brain has to do with a damaged corpus callosum, which connects the two heispheres

• Split brains cannot communicate from side to side, meaning many functions of the brain are limited

• We continue to study this decades after the initial experiments

Visual Fields

• We process what we see on the opposite side that the eye is on

• The right visual field is processed the in left visual cortex

  • With a split brain, individuals can still say what they saw, because the language areas are in the left hemisphere

• In the left visual field, which is processed by the right visual cortex, they can draw what they saw, but not say it

• This is how we came to the basic conclusion that the left side of the brain handles logic, and the right side handles vision/abstract/material features

• This is a general assumption, because we are not “left-brained” or “right-brained”

  • We use our whole brain, all the time, for all functions

  • Even split brain patients are always using all of their brain, the two hemispheres just can’t communicate

Modern Methods of Data Collection

Electroencephalogram (EEG)

• Electrodes are placed on the head

• They detect electrical activity from firing neurons

Positron Emission Tomography (PET)

• The individual is injected with trace amounts of radioactive glucose

• PET scans detect “hot spots” of cellular activity

  • Meaning spots with high neural firing

  • As neurons fire, they consume glucose

• This enables us to map activity with a visual depiction

• It shows us the brain in action, and where activity travels

Magnetic Resonance Imaging (MRI)

• The individual is placed in the large MRI machine

• A low-level magnetic field is created

• A pulse distorts the magnetic field and atoms in the body

• As atoms return to normal, the MRI machine is able to produce very detailed images of brain slices

• This can give a great amount of information on brain anatomy

• It is also used to compare healthy and unhealthy brains

Functional Magnetic Resonance Imaging (fMRI)

• The process is very similar to an MRI

• Rather than measuring the activity of atoms, this measures oxygen from blood flow

• This reveals a lot about both brain anatomy and activity

• Shows both detailed slices of the brain alongside “hot-spots” like in the PET scan