Week 3: Research Methods

Question 1

Levels of Analysis

Answer 1

Different levels of looking at the brain and it’s structures and functions. Macro and micro levels

Question 2

Spatial resolution

Answer 2

Ability to measure smaller brain structures; High SR = smaller areas

Question 3

Temporal resoltion

Answer 3

Ability to measure change in activity in time units; high TR = fast measurement

Question 4

Why measure human brain activity

Answer 4

Compare resting control brain and active brain to assess patterns of activation. Can be used to define and diagnose disorders

Question 5

Electroencephalogram (EEG)

Answer 5

Picture of the brain taken using electrodes on the scalp that measure the neurons directly below them (small area). Measures the wave-like frequencies over time and correlate the patterns to a brain state.
Low spatial, high temporal

Question 6

Event-related potential (ERP)

Answer 6

Measured in an EEG. Neural activity of brief mental processes. Averaged across many records to determine patterns of activity

Question 7

Positron Emission Tomography (PET)

Answer 7

Develop radio tracers that act like a desired chemical, but generate gamma rays. Rays are tracked and generate colored images (blue = less activity, red = more). Theoretically can be used to diagnose disorders.
Decent spatial, low temporal

Question 8

Magnetic Resonance Imaging (MRI)

Answer 8

Strong magnetic field aligns the spin of your brain atoms to its pull. When they realign, it send a signal to the machine and builds a picture. Not used in individual diagnoses, but results are averaged to get a basic idea of disordered brains.
High spatial resolution

Question 9

Diffusion tensor imaging (DTI)

Answer 9

MRI but for white matter structure. Can be used to correlate white matter tracts and disorders

Question 10

Functional MRI (fMRI)

Answer 10

Tracks change in ratio of oxygenated to deoxygenated blood. Typically only used in correlational findings
High spatial, decent temporal

Question 11

Issues with fMRI (and MRI to an extent)

Answer 11

Reverse inference. Results can differ from natural activity due to lab environment. Expensive, inconvenient, and requires a trained professional

Question 12

Reverse inference

Answer 12

Assuming psychological activity from brain images. This causes issues because brain areas can light up for many different processes, so assumptions can ignore possibilities or cause errors in judgement

Question 13

Lesion studies

Answer 13

Tracking behavior changes after damage or injury to the brain. Rarely used; case studies; rarely specified to just one brain area

Question 14

Micro-level measuements

Answer 14

Single cell recordings: measuring one cell via electrode insertion. Irreversible damage, only done when necessary
Gene/protein expression measurements: How much, what type, and epigenetic changes in protein
IHC

Question 15

Immunohistochemistry (IHC)

Answer 15

Develop antibodies to tag cells of interest and generate an image of specific cell types in dead brain tissue

Question 16

Uses of manipulating brain function

Answer 16

Can experimentally determine causal relationships between neurology and behavior

Question 17

Transcranial magnetic stimulation (TMS)

Answer 17

Targets specific brain areas with magnets and exhausts the neurons to temporarily shut off function. (TCDS is the same but using electrons instead of magnets)

Question 18

Deep Brain Stimulation (DBS)

Answer 18

Penetrate the brain with an electrode. Highly invasive, used primarily in treatment scenarios

Question 19

Drug manipulation

Answer 19

Give drugs to temporarily change brain function.
Agonists = activate receptors
Antagonists = inhibit receptors
Allosteric modulators = tune the system

Question 20

Benefits of animal brain manipulation

Answer 20

We can more readily do highly invasive procedures ethically and cheaper

Question 21

Electrophysical animal recordings

Answer 21

Single cell readings, can be used to map distinct cell function

Question 22

Targeted manipulation studies in animals

Answer 22

Surgically alter brain areas to observe behavior change. Done via lesion (irreversible, electrodes) or pharmacologically (reversible, cannulae)

Question 23

Genetic studies in animals

Answer 23

Manipulate genes to track behavior change. Take out genomes or add modified genomes. Can restrict modification to selective (specific gene) or inducible (timed).
Not generalizable

Question 24

Optogenetics

Answer 24

Target single cell populations and manipulate them via direct light stimulation. High spatial and temporal resolution

Question 25

Chemogenetics

Answer 25

Target single cell populations and manipulate them via drug stimulus. High spatial, low temporal

Question 26

Behavior testing in animals

Answer 26

4 types. Anxiety tests, Depression-like behavior tests, memory process testing, Social Interaction tests

Question 27

Elevated plus maze

Answer 27

Knee height, cross shaped, two arms open and two arms closed. Track how long the mouse spends in each arm. More time in closed arms = more anxious

Question 27

Anxiety tests in animals

Answer 27

Determine baseline anxiety level in animal using the elevated plus maze. Done before other test to rule out confounds in other behaviors

Question 28

Depression-like tests in mice

Answer 28

Modelling depression symptoms and anhedonia. Swim test, tail hang test. Giving up = depressed behavior

Question 29

Memory process tests in mice

Answer 29

Fear conditioning for LTM: Operant conditioning to fear. Measure amount of freeze response. Expression of learned fear implies memory Object recognition for STM and LTM: Train with toys, give them a break, and then test them with old and new toys. More exploration of novel toys implies memory

Question 30

Three-chamber Social Interaction Test in mice

Answer 30

Phase 1: mouse on its own Phase 2: give it a friend Phase 3: give it another friend Measure amount of time spent with first friend (sociability) and attraction to second friend (attraction to social novelty) Used to study social disorders

Question 31

Modelling Autism in mice

Answer 31

Replicate poor social interaction, repeating behaviors, long slow development, etc. Use valporic acid (VPA) in mother mice to give children 9-fold chance of presenting with ASD. (VPA works in humans and mice)