PSY 211- exam one (approaches)

What are the three main approaches for using brain activity to examine cognitive processes

Lesioning, stimulating the brain area and measuring cognitive processes, and measuring activity while cognitive process engaged 

Single-Unit Recording

• How: Records electrical activity from a single neuron using an electrode.

• Tells us: Exactly when and how an individual neuron responds to a stimulus/task.

• Advantage: Extremely precise at the individual-neuron level.

• Limitation: Usually invasive, so it is mainly used with animals or in special

fMRI — Functional Magnetic Resonance Imaging

• How: Measures changes in blood oxygenation associated with brain activity.

• Tells us: WHERE activity is happening in the brain.

• Strength: Excellent spatial resolution → can pinpoint activity to relatively small brain areas.

• Weakness: Poorer temporal resolution → slower than EEG because blood-flow changes take time.

PET

• How: Uses a radioactive tracer to measure metabolic activity/blood flow in the brain.

• Tells us: WHERE and how much metabolic activity is occurring.

• Can also measure certain neurotransmitter/receptor systems.

• Weakness: Lower spatial/temporal resolution than fMRI and involves radioactive material.

Brain Stimulation

• How: Artificially changes activity in a particular brain region.

• Examples include TMS (transcranial magnetic stimulation)--> magnetic above head 

• Tells us: Whether changing activity in an area causes changes in behavior or cognition.

• Key advantage: Helps establish causation, not just correlation.

EEG — Electroencephalography

• How: Electrodes placed on the scalp measure the brain's electrical activity.

• Tells us: Overall patterns of brain activity, especially WHEN activity occurs.

• Strength: Excellent temporal resolution—can measure changes within milliseconds.

• Weakness: Poor spatial resolution—harder to determine exactly where activity originated.

ERPs — Event-Related Potentials

• How: Uses EEG data and averages the brain's electrical responses to a specific stimulus/event.

• Tells us: When specific stages of cognitive processing occur.

• Example: Can show how quickly the brain responds to a particular visual or auditory stimulus.

PET and fMRI

have good spatial resolution but poor temporal resolution

ERPs

have good temporal resolution but poor spatial resolution

Localization of function

is the idea that specific areas of the brain are specialized for specific cognitive functions or behaviors (Different brain regions perform different jobs)

It shows that cognition is supported by

different specialized brain areas, rather than the entire brain doing the same thing.

Magnetoencephalography (MEG)

A non-invasive neuroimaging technique that measures the magnetic fields produced by neural activity in the brain. These magnetic fields are generated by electrical currents in neurons

Near-Infrared Spectroscopy (NIRS)

A non-invasive imaging technique that uses near-infrared light to measure changes in blood oxygenation and blood volume in the brain. NIRS can infer the levels of oxygenated and deoxygenated hemoglobin in the brain by producing near-infrared light and detecting the light that is reflected.

Diffusion Tensor Imaging (DTI)

A specialized type of magnetic resonance imaging (MRI) that focuses on measuring the diffusion of water molecules in human (or other animal) tissue, particularly in white matter tracts of the brain. This technique allows for the visualization and mapping of the brain’s structural connectivity by revealing the pathways of white matter fibers.