← PSY 1: Introduction to Psychology

Unit 5: Methods of Studying the Brain

How psychologists find out what a piece of brain tissue actually does, from century-old lesion cases to modern imaging.

4 topics · 12 questions

Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.

The Lesion Method

  1. How it worksHow does comparing what a person can no longer do after damage to one brain area reveal what that area was doing?
  2. Common mistakeWhy doesn't a lesion study prove an area is the only place a function happens?
  3. Going furtherWhat happens to a conclusion from a single famous lesion case once dozens of similar cases are compared instead?
Your turn1 of 2
Phineas Gage survived a metal rod blown through his frontal lobe, and the personality changes that followed taught psychologists something decades of studying intact, undamaged brains never revealed. A student assumes simply observing an intact, healthy brain in action should already show researchers everything a brain region does. How does comparing what someone can no longer do after damage reveal what a brain area was doing?

EEG and the Timing of Brain Activity

  1. How it worksHow does EEG pick up the combined electrical activity of millions of neurons firing together?
  2. Worked exampleFind why a brain wave that appears 300 milliseconds after a surprising stimulus gets its name, the P300.
  3. Going furtherWhat happens to EEG's usefulness when a researcher needs to know which of two nearby brain structures produced a signal?
Your turn1 of 2
An EEG researcher records a brain wave peaking 463 milliseconds after a surprising stimulus. Find this latency in seconds.

fMRI and the Blood-Oxygen Signal

  1. How it worksHow does an active brain region pull in extra oxygenated blood that fMRI detects a few seconds later?
  2. Going furtherWhat happens to fMRI's picture of brain activity when you compare it to EEG's picture of the exact same task?
  3. Common mistakeWhy isn't a lit up region on a brain scan the only part of the brain doing any work?
Your turn1 of 2
An fMRI scanner does not measure neurons firing directly, but instead measures changes in blood oxygenation a few seconds after neural activity occurs. A student assumes this indirect measurement must mean fMRI is not really telling researchers anything about brain activity at all. How does an active brain region's blood flow actually reveal that activity?

TMS and Causal Evidence in Neuroscience

  1. How it worksHow does transcranial magnetic stimulation let researchers test what a brain area does, instead of only observing it?
  2. Common mistakeWhy doesn't a correlation between brain activity and behavior prove that brain area causes the behavior?
  3. Ties togetherHow does TMS answer the causation question that a purely correlational fMRI study can't?
Your turn1 of 2
A researcher wants to know not just which brain area is correlated with a task, but whether that area actually causes the behavior involved. A student assumes any brain-imaging method should already answer that causal question just by showing which area is active. How does transcranial magnetic stimulation let researchers test what a brain area does rather than only observe it?