Cognitive neuroscience - methods

What are the approaches to measurement?

• Monitor brain activity while engaging in a specific activity to establish underlying patterns during behaviour/cognition

• Manipulate brain systems & examine effect on behaviour/cognition

What are psychological methods?

• Used as indicator of behaviour/cognition to be correlated with brain activity

• Types: cognitive, survey, observational

• No insights into underlying outcomes

What is electroencephalography?

• Non-invasive, electrodes placed on skull

• Measures electric potentials across the brain

• EEG signals averaged over many events, electrodes record positive & negative peaks, timing & amplitude of peaks recorded

• Resting state: continuous recording of brain activity

• Event-related potentials: linked to a specific event

• Strengths: excellent temporal resolution & non-invasive

• Weaknesses: poor spatial resolution & requires many trials

What is functional imaging?

Measures blood flow, blood oxygenation, or metabolism associated with neural activity

What is functional magnetic resonance imaging (fMRI)?

• Non-invasive

• Measures using hemodynamics

• Changes in BOLD signal over time is hemodynamic response function

• Strengths: high spatial resolution, non-invasive

• Weaknesses: poor temporal resolution, expensive, sensitive to movement

What is functional near infrared spectroscopy?

• Non-invasive, portable, less sensitive to motion artifacts

• Uses same BOLD signal as fMRI but with near-infrared light

• Strengths: non-invasive, quiet, portable, flexible, reasonable temporal resolution

• Weaknesses: limited spatial resolution, depth

What is magnetoencephalography?

• Non-invasive, silent, sensitive to motion artifacts

• Measures magnetic fields produced by electrical activity in brain

• Neurons fire → electrical currents → generates small magnetic fields

• Strengths: non-invasive, quiet, high temporal resolution, good spatial resolution

• Weaknesses: expensive, limited depth sensitivity, participants must remain still

How can you disrupt brain function?

Through experimentally induced lesions or naturally occurring lesions

How can naturally occurring lesions be used?

• Strengths: can indicate causal relationships between brain regions & behaviours/cognitive processes, unique insights into ecologically & clinically relevant contexts

• Weaknesses: variability, individual differences, brain plasticity

What is transcranial magnetic stimulation?

• Non-invasive

• Electromagnetic coil placed against scalp

• Pulses of electricity send magnetic fields to stimulate neurons

• Strengths: helps establish causal relationships, non-invasive, reversible, can be combined with other methods

• Weaknesses: limited to surface cortical regions, effects can be variable