research methods Flashcards
Animal research methodes vs human research
Animal Research
Imaging
Manipulation
Human Research
Neuroimaging
Neural manipulation
Neuropsychological assessment
What is stereotaxic surgery?
What is the reference point?
What is the map?
Used to position experimental devices
within the brain
Stereotaxic atlas – provides coordinates for
locating structures within the brain
Bregma – a point on the top of the skull
often used as a reference point
Sterotaxic instrument – used to hold head
steady and guide the device to be inserted
Electrical Stimulation
What’s it used for?
how does it work?
Lesioning can be used to remove,
damage, or inactivate a structure.
Electrical stimulation may be used to
“activate” a structure.
Stimulation of a structure may have an
effect opposite to that seen when the
structure is lesioned.
What are some Invasive Electrophysiological
Recording Methods
Intracellular unit recording: Membrane potential of a neuron
Extracellular unit recording:Firing of a neuron
Multiple-unit recording:Firing of many neurons
Invasive EEG recording: Surgically implant electrodes into the brain measure electrical activity
What are some ways drugs can be administered?
Fed to the stomach
Injected - described by injection sight:
stomach (intragastric)
peritoneal cavity (intraperitoneal, IP)
large muscle (intramuscular, IM)
tissue under the skin (subcutaneous, sc)
large surface vein (intravenous, IV)
Cannula – used to administer drug directly
to brain
Explain how Selective Chemical
Lesions work
Neural poisons (neurotoxins) selectively
target specific nervous system
components
Kainic or ibotenic acid – destroy cell
bodies
6-hydroxydopamine (6-OHDA) –
destroys noradrenergic and
dopaminergic neurons
2-Deoxyglucose (2-DG) technique
Inject animal with radioactive 2-DG and allow it to
engage in behavior of interest
Use autoradiography to see where radioactivity
accumulates in brain slices
Cerebral dialysis
Cerebral dialysis – measures extracellular concentration of specific chemicals in live animals
inserting a small, semipermeable probe into a specific brain region, allowing the exchange of extracellular fluid with a perfusion solution. This enables researchers to collect and analyze neurochemicals such as dopamine, serotonin, and glutamate while minimizing damage to brain tissue.
Locating Neurotransmitters and
Receptors
Immunocytochemistry
Based on the binding of labelled protein-specific antibodies to detect proteins.
Immune response:
Antibodies are produced to bind and neutralize antigens (foreign proteins).
Labels can be fluorescent dyes, enzymes, or radioactive markers.
In Situ Hybridization (ISH):
Uses labelled RNA probes to detect neurons with complementary mRNA.
Helps identify gene expression patterns in specific cells or tissues.
Human research Non-invasive “Neuroimaging” methods:
Structural imaging
Functional imaging
Neuropsychological
Invasive Neural “Manipulation”
Human research
Stimulation
Ablation
Case Studies
Explain how cerebral angiograms work
Opaque dye injected into cerebral arteries
Used primarily for examining the cerebral vasculature
Computed tomography (CT scan)
How does it work?
series of X-rays
combined to form a 3-D representation
MRI
What do the letters stand for??
Better or worse than ct?
How does it work
Magnetic Resonance
Imaging (MRI)
Better spatial resolution than CT scan
Hydrogen atoms align under powerful
magnetic field
Electromagnetic pulses are bounced off the aligned hydrogen atoms
Diffusion tensor imaging (wow)
- Makes use of MRI
technology - Maps out tracks of white
matter
*Clinical applications
Functional neuroimaging types
Functional: fMRI (functional magnetic resonance imaging)
PET (positron emission tomography)
EEG (electroencephalography)
MEG (magnetoencephalography)
How do fmri’s work?
Whats it good at and bad at?
What does it mesure?
Measures changes in oxygen utilization
BOLD response (blood oxygen level
dependent)
Good spatial resolution
Relatively poor temporal resolution
Explain PET scans
Radioactive 2-DG
Injected into carotid artery
Shows glucose metabolism
Poor spatial resolution
Relatively poor temporal resolution
EEG
Measures electrical activity on the
surface of the cortex
Often used for diagnosis of epilepsy
Poor spatial resolution
Great temporal resolution
Good bad and goals of Neuropsychological
Testing
Assists in diagnosing neural disorders.
Time-consuming - only conducted on a small portion of those with brain damage
Serves as a basis for counseling/caring
Provides information on baseline function
Neuropsychological
Testing
Single-test – Early approach
Used to differentiate brain damage from
functional (psychological) causes
Standardized-test-battery
Same goal as single-test approach
Halstead-Reitan, Luria-Nebraska
Customized-Test-Battery or
Flexible Battery Approach
Goal is to characterize the nature of the deficits seen in the brain-damaged
patient
Begin with a general test and then follow with tests designed to explore the nature of the observed problems
Common Components of the
Initial Common Test Battery
Wechsler Adult Intelligence Scale
WAIS, an IQ test
Often fails to detect memory deficits
Token test
Can detect language-related deficits
Language lateralization – used to identify
language-dominant hemisphere
Sodium amytal – anesthetize one hemisphere
Dichotic listening – ear contralateral to dominant
hemisphere shows superior hearing ability
Ablation and stimulants in human neurological testing
aspiration, radio-frequency, surgical removal, cryogenic
Interpretation of lesion effects
Stimulation
TMS (transcranial magnetic stimulation)
Electrical stimulation
Pharmacological
TMS
Not extremely invasive, but more
invasive than MRI
Strong magnetic field is focused in order
to temporarily disrupt neuronal
functioning
Essentially a temporary ablation
Deep Brain Stimulation
How it is used
What’s it used for
An electrode is surgically place in the brain
Controlled with a pacemaker-like device that sends electrical impulses
Used to treat various disorders including:
Parkinson’s disease
Tourette syndrome
Major Depressive Disorder
Cognitive Neuroscience
Assumptions
Each complex cognitive process results
from the combined activity of simple
cognitive processes (constituent
cognitive processes)
Each complex cognitive process is
mediated by neural activity in a particular
area of the brain
Describe the forms of structural and functional neuroimaging discussed in class. Be sure to note the important key aspects of each technique.
Structural Neuroimaging:
◦ Angiogram: This involves injecting an opaque dye into cerebral arteries to examine cerebral vasculature.
◦ CT Scan (Computed Tomography): This method uses a series of X-rays combined to form a 3-D representation of the brain.
◦ MRI (Magnetic Resonance Imaging): MRI has better spatial resolution than CT scans. It uses a powerful magnetic field to align hydrogen atoms and bounces electromagnetic pulses off these atoms.
◦ DTI (Diffusion Tensor Imaging): DTI uses MRI technology to map out the tracks of white matter in the brain. It also has clinical applications.
Functional Neuroimaging:
◦ fMRI (Functional Magnetic Resonance Imaging): fMRI measures changes in oxygen utilization, known as the BOLD (blood oxygen level dependent) response. It has good spatial resolution but relatively poor temporal resolution.
◦ PET (Positron Emission Tomography): PET involves injecting radioactive 2-DG into the carotid artery to show glucose metabolism. It has poor spatial and temporal resolution.
◦ EEG (Electroencephalography): EEG measures electrical activity on the surface of the cortex and is often used for diagnosing epilepsy. It has poor spatial resolution but great temporal resolution.
◦ MEG (Magnetoencephalography): MEG is primarily used for research purposes and has good spatial and great temporal resolution. However, it is expensive.
