Methods of Psychology

Causes of brain damage

Tumors, degenerative and infectious disorders, vascular disorders, and TBIs

What is the use of brain lesion studies?

They tell us how damage to certain areas can cause altered functioning

What types of animals are used for brain lesion studies?

Rats, and cats for vision studies

Genetic knockout models

Deactivating a gene in order to determine its function, only used in animal studies

Callosotomy

Severing of the corpus callosum, done for epileptic patients. Can have the long-term effects of not having internal monologues and disconnection syndrome

Optogenetics

Genetic manipulation

TMS

Active study method using magnetic stimulation to excite or inhibit areas of the brain

Agonist drugs

Drug that mimics the effects of a neurotransmitter

Antagonist drug

Drug that bind to receptors and blocks or dampens neurotransmission

Issues with active methods

Lack of specificity

Passive measuring of the brain

Any type of structural analysis of the brain

CT or CAT scan (computed tomography)

Provide detailed cross-sectional images of the brain using x-rays

Downsides of CT scans

Low resolution

MRI (Magnetic resonance imaging)

Uses the magnetic properties of elements like hydrogen to create high resolution images of the brain, giving both structural and functional analysis

How does white and grey matter affect MRI scans?

The density of hydrogen atoms are different in grey and white matter, allowing these regions to be distinct on MRI scans

What do MRIs measure?

Rebound of disrupted hydrogen protons

Benefits of MRIs over CTs

Higher resolution

DTI (Diffusion Tensor Imaging)

MRI technique that maps white matter tracts through tracking water movement, showing structural connectivity and informational flow

Why can we see axon tracts on DTI scans?

Axon tracts have a lipid barrier formed by the myelin sheath, which differs from the water movement in the non-fatty part of the brain

Single-cell neurophysiology

An invasive passive measuring method used for epilepsy research that uses an electrode to measure the activity of one neuron, typically left in the extracellular fluid

Electrocorticography (ECoG)

Invasive passive measurement that picks up electrical activity in the brain, recording from the cerebral cortex

Magnetoencephalography (MEG)

Measures magnetic fields generated by neural activity, showing brain function with high temporal resolution (when), but low spatial (where) resolution

EEG (Electroencephalography)

Measures electrical activity in the brain, and shows us real-time information

Event related potentials

EEG technique used to measure the brain’s response to certain stimuli, used for studying information and cognitive processing

Functional Magnetic Resonance Imaging (fMRI)

Records magnetic changes from the brain using the rebounds of radio waves from the MRI machine

What do PET and fMRIs measure?

Metabolic changes associated with neural activity

What are the benefits of fMRI scans?

Non-invasive and less expensive

Drawbacks of fMRI scans?

Low temporal resolution

Positron Emission Tomography

Older technology that records radiation from a radioactive tracer to see metabolic changes

Drawbacks of PET scans

Expensive, tracer has a decay time, and has some cancer risk

Magnetic Resonance Spectroscopy

Estimates the concentration of neurotransmitters