Methodology Flashcards
Noninvasive techniques
CT =>
EEG => ElectroEncephaloGraphy OR
ERP=> Event Related Potential
PET =>
DTI =>
MRI (fMRI) => functional Magnetic Resonance Imaging
NIRS =>
MEG =>
TMS => Transcrnial Magnetic Stimulation
Invasive techniques
ECoG =>
SEEG =>
Intracortical implants
TransCranial Magnetic stimulation (TMS)
How it works?
We have magnetic field pulses applied with coil.
Change in the magnetic field cause weak current on the surface of the brain
What does TMS do?
Depending on the target and strength of impulse, it stimulates neural activity and stops the neurons from talking
Pros and cons of TMS
Ask questions about activity (inactivity) of targeted regions
Only surface structures
Temporary lesion
Independent variable
The factors those are manipulated by the experiment.
Dependent variable
The factor those are measured in experiment to monitor the change in response to manipulation of independent variables.
Define EEG/ERP
It measure the electrical potential of brain with electrodes on a cap
We cannot tell from where the neurons
EEG help diagnose which disease with alters
Autism spectrum disorder
ERP has latency and amplitude, define latency? Define amplitude?
Latency: how long after the stimulus onset did the ERP occur?
Amplitude: how large is the neural response.
What does fMRI measure
It measures the localized activity in brain
Blood-Oxygenation Level Dependent BOLD signal
It has great spatial resolution but not temporal
Steps of MRI
Measures the resting membrane potential
Let the participants do the activity in the scanner
Compare activation patterns across conditions
What is difference and same between EEG and MRI
MRI is good with spatial resolution and EEG is good with temporal resolution.
EMR measure localized activity and EEG measure the surface of brain
Benefits of non-human model for invasive techniques
Ability to study the brain of living organism with invasive tech. For example if measuring neural activity then it has better spatial resolution
What things done in invasive techniques?
• ablation
• direct measure to the brain activity
• temporary lesions
• manipulation of brain activity
Ablation
Remove the brain structure or sever the connections
Then study the effect on animal’s brain
Temporary lesion
Cool down region of interest witch stop or slow the neural activity
Pharmaceutically disturbs neuron from firing
Direct measure of brain activity
• Electrophysiology
• Extracellular recording
• Activate neurons/ brain area with electrodes
• Measure brain chemistry with microdialysis
Electrophysiology
Use of microelectrodes to measure the electrical activity of a cell
Extracellular Recording
Place microelectrode in the Extracellular space near the cell
Measure 1-100s neurons
Manipulation of brain activity
• Optogenetics is 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
Condition for intracellular recording
Surface of the cell must be accessible to the electrode
What help intracellular recordings
• Allows you to record electrical events within neurons (not just signaling between neurons)
Methods to visualizing gene/Protein expression
• In situ hybridization
• Immunohistochemistry
• Autoradiography
In situ hybridization
Uses complementary probes to find neuro with a specific mRNA sequence.
Immunohistochemistry
• Antibodies detect expression of specific proteins.
• Can tell you which cells express a certain protein, and where within a cell that protein is expressed.
Autoradiography
• Synthetic radioactive probes bind to a protein of interest
