S2 Methods of Social Neuroscience

Metrics for Methods

Spatial Resolution

Temporal Resolution

Invasiveness

Spatial Resolution

Accuracy of where an event is occuring

Temporal Resolution

Accuracy of when an event is occuring

Invasiveness

How much the measurement or instrument invades the body

fMRI

Uses BOLD (blood oxygen level dependent) to infer brain activity and include HEMODYNAMIC RESPONSE FUNCTION to see when it occurs.

• MRI gives structural information only, like how amygdala size changes with emotions but fMRI does that and gives information about amount of activation

• more neural activity, more oxygen delivered in that area

• Doesn’t directly measure brain activity, measures blood oxygen changes

fMRI conditions

Experimental condition

Control condition, keep stimulus as similar as possible as experimental condition

Fixation condition, no stimulus and just looking at fixation cross on screen

PET

Measures local blood flow using radioactive tracer

Difference from fMRI is, it uses receptor specific tracers to map certain receptors and protein locations

Is injected into the bloodstream

fMRI vs PET

fMRI has better spatial and temporal resolution

fMRI is faster than PET

fMRI does not use radioactivity

fMRI allows event related designs

PET can be used to trace distribution of receptors and proteins

fMRI AND PET

Advantages

• Good spatial resolution

• Noninvasive

Disadvantage

• Not direct measure of brain activity

• Poor temporal resolution

VBM

Voxel Based Morphometry

• Structural based imaging using voxels (pixels) to determine size/volume of brain regions

• Compares groups of brain structures through looking at grey matter

Article EXAMPLE

• London taxi drivers had larger hippocampus

DTI

Diffuser Tensor Imaging

• Identifies white matter tracks and connectivity of brain regions through diffusion of water molecules

ex.

amygdala and PFC are less connected in individuals with depression than controls

VBM and DTI

Advantages:

• Enables full brain structure analysis and permits asking questions regarding it

• Utilizes MRI which is insanely available and not invasive

Disadvantages

• Correlates stuff but doesnt show causes

Lesions

Damages to specific brain regions

• Tumor

• Cell death

• Epilepsy

• Infections

Use in research

• Good for exploring casual relationships between brain and behavior

Neuropsychology

• Infer function of a region by removing it and seeing the behavior of cognitive change

Mostly used on animals

Lesion Advantages and Disadvantages

Advantages

• Enables inferences about brain behavior causality

Disadvantages

• No experimental control

• Concern about animal health

• Lesions don’t impact only one part of the brain

TMS

Transcranial Magnetic Stimulation

• Stimulates regions of the brain that induce magnetic field using a current

• Temporary lesion is made

Advantage

• Can be used to stimulate or inhibit activation to see if that brain region is important for a task —> inference

Disadvantage

• Cant say for certain that only one brain region is affected and only a few parts of the brain

• Some individuals cant even partake in this bc of conditions like epilepsy and pacemakers