Methodology Flashcards
What are pros of studying the human brain via damage?
- Learn a lot about a particular brain region
- Work in a human system
What are cons of studying the human brain via damage?
- Damage is often messy
- Very disruptive of individual’s life
- Case studies
TMS is short for…
Transcranial magnetic stimulation
When was TMS first introduced?
1980s
What tools are used during TMS and how?
Magnetic field pulses are applied through a coil
What causes weak electrical currents on the surface of the brain for TMS?
Changes in the magnetic field
What does TMS do depending on the targeted region and strength of the impulse?
- Stimulate neural activity
- Stop neurons from communicating
What are pros of using TMS?
- Ask CAUSAL questions about activity (or inactivity) of targeted brain regions
- Temporary lesion
What are cons of using TMS?
-Surface structures only
EEG has been around since the…
1920s
What does EEG stand for?
Electroencephalography
What does EEG measure and how?
It measures the electrical potential of the brain through electrodes
EEG is great measure for ________ in the brain, but not great for ________ of activity.
timing of activity
spatial location
True or False:
EEG can be used with infants and children
True
EEG activity can be measured when a person is…
At rest for clinical diagnostic reasons
Example: Research has shown that certain EEG patterns may be an early marker for autism spectrum disorder
When utilizing EEG for research, what is often presented and recorded?
Often present stimuli and record Event-Related Potentials (ERPs)
Note: stimuli could be words and nonwords for example
True or False:
EEG picks up on activity from specific neurons
False.
EEG picks up on general activity over an area, not specific neurons.
ERPs have _______ and _______.
Latency and Amplitude
What is latency?
How long after the stimulus onset did the ERP occur?
What is amplitude?
How large is the neural response?
Typical ERPs have been identified and are thought to relate to ________.
Cognitive functions
ERPs can be measured across _________.
Different electrode sites.
fMRI stands for…
Functional Magnetic Resonance Imaging
fMRI has been used since the…
1990s
fMRI measures ________.
Localized activity in the brain
fMRI analyzes what signal?
The BOLD Signal
Blood-Oxygenation Level Dependent Signal
Why does fMRI have great spatial resolution but not-so-great temporal resolution?
Because blood flow is sluggish
fMRI measures…
Resting State
What is an example of how fMRI may be used?
Have participant perform tasks in the scanner and compare activation patterns across conditions
How does one analyze data in a study using fMRI?
Align each functional run to the anatomical run. Data from each condition is averaged together
In a study for fMRI, _________ are performed.
whole-brain contrasts
What are the 4 key characteristic of TMS?
- Good temporal resolution
- Only used to study surface-level brain structures
- Stimulates or inhibits brain activity
- Makes use of properties of magnetism
What are 3 key characteristics of EEG/ERP?
- Good temporal resolution
- Indirectly measures brain activity
- Sensitive to eye-blinks and muscle tension
What are 4 key characteristics of fMRI?
- Good spatial resolution
- Indirectly measures brain activity
- Sensitive to motion artifacts (must stay still during procedure)
- Makes use of properties of magnetism
What are the benefits of a non-human animal model?
- Ability to study the brain of a living organism using invasive techniques (still with ethical practices)
- If measuring neuronal activity - better spatial resolution than noninvasive techniques
What is an ablation?
Remove brain structure or sever connections
What do ablations study?
Effects on animal behavior
What are temporary lesions?
Cool down region of interest to slow/stop neural activity
OR
Pharmacologically disrupt neurons from firing
What is electrophysiology?
The use of microelectrodes to measure the electrical activity of cells
What is extracellular recording?
Place microelectrode in extracellular space near a cell.
1 to 100s of neurons detected
Electrodes can also be used to activate neurons/brain areas
What does microdialysis measure?
Brain chemistry
What are direct measures of brain activity?
- Electrophysiology
- Extracellular recording
- Microdialysis
What is optogenetics?
The use of genetic tools to induce neurons (or other cells) to become sensitive to light, such that experimenters can excite or inhibit a cell by exposing it to light
How does optogenetics work?
Introduce genetic material into cells that allow them to express a channel sensitive to light.
Shine light into brain - only cells expressing channel will be excited.
Single-cell recordings are also referred to as
in vitro
How can one look at brain tissue to understand it at a cellular level?
Using microscopy - prepared with various staining techniques
In intracellular recordings such as electrophysiology, the surface of a cell must be ________.
Accessible to recording electrode
What do intracellular recordings allow?
It allows for you to record electrical events within neurons (not just signaling between neurons)
Cells have complete ______ but only express certain genes.
Genomes
What makes cells take on unique functions?
Differential gene expression
What are the different methods that allow us to label neurons that express specific mRNA sequences or proteins?
- In situ hybridization
- Immunohistochemistry
- Autoradiography
What is In Situ Hybridization?
It uses complementary probes to find neurons with a specific mRNA sequence
What is immunohistochemistry?
Antibodies detect expression of specific proteins.
It can tell you what cells express a certain protein, and where within a cell that protein is expressed.
What is autoradiography?
Synthetic radioactive probes bind to a protein of interest
There is a trade off between ______ and ______ resolution
Temporal and Spatial
