How Psychologists Study the Brain

Accidents

•Brain damage due to:▫Whiplash: aka – diffuse axonal injury

Stretching, twisting, damage to the axon▫Isotropic Stress: high speed change scenarios

Car crash, explosions, sky-diving, etc Creates a “pressure wave” or pulse Causes damage to neurons

•Psychologists/Doctors examine:▫Loss of Vision▫Loss of Hearing▫Loss of Memory▫Confusion

LesionsDef: cutting the brain, removing portions of the brain

•Commonly done in the past•Today: lobotomy

▫Last resort, experimental surgery McDreamy

▫Observe and document changes▫Animal experimentation commonly performed

Are correlations reliable and valid?•Harvesting brains of the dead

▫Concussion victims, dementia, Alzheimer's, schizophrenia, etc

Electroencephalogram (EEG)

• Why would you get one?▫ Sleep Disorder▫ Having Seizures

(epilepsy)▫ Determine “brain death”

• How does it work?▫ Electrodes attached to the

scalp (exterior)▫ Perform mental function

or physical action▫ Brain waves produced &

recorded

EEG Readings

Electrical Brain Stimulation (EBS)

• How: ▫ Electrodes attached, inserted

in the brain (interior)▫ Charge emitted▫ Measure results performed by

patient• Findings

▫ Specific regions of the brain linked to sensory or motor cortex regions

▫ Ventral Nerves: neurons sending messages to the brain Epilepsy patients OCD subjects

Computerized Axial Tomography (CAT) Scanaka – CT scan

• Why would you get one?▫ Car accident▫ Suspected concussion▫ Locate blood clot,

infection, or tumor• How is it done?

▫ X-ray of the brain▫ Brain absorbs radiation

and computer produces an image

• Can be done on any organ

CAT ScansHealthy Brain

ScansAbnormal Brain

Scans

Magnetic Resonance Imaging (MRI)• Why would you get one?

▫ CAT Scan inconclusive▫ Looking for a tumor or

aneurism▫ Examine bleeding in the brain▫ Damage to optic or auditory

nerves• How does it work?

▫ Brain produces “energy”▫ Computer measures radio

waves▫ Looking for abnormalities,

“hotspots”

MRI Images

A Brain on “MS”Healthy Brain

Positron Emission Tomography (PET) Scan

• Why would you have one?▫ To confirm CAT Scan▫ To measure blood flow▫ Diagnose: Alzheimer’s,

Parkinson’s, MS, ALS, or Cancer (lymphoma)

• How does it work?▫ Chemical injected

(glucose)▫ Chemical “lights-up”▫ Image captured

PET & CT Machines often are the same

PET Scan ImagesSchizophrenia Experiment Alzheimer’s Patient

PET scans of five normal individuals (left); each row is one person, and each image is a slice from five different levels of the person's brain. The red areas show regions of the brain that are activated when a person performs a memory task. In PET scans of five individuals with schizophrenia (right), each row represents a different person, with comparable slices. Clearly, the patients with schizophrenia do not generate the dramatic brain activity in the circuits of the brain critical to the memory task.