HMB200H1 Study Guide - Final Guide: Clozapine, Receptor Activated Solely By A Synthetic Ligand, Designer Drug
1. What is an animal model? Why do we use animal models?
An animal model (animal studies) is study conducted on animal. We use animal
models because many experimental studies of the brain are impossible in human
for ethical, moral and logistic reasons
2. Why do we prefer mice for virtually all animal studies? Why do we strongly
prefer them for transgenic models?
We prefer mice because they have similar genome structure and gene number to
human. We strongly prefer them for transgenic models because they are cheap
and easy to maintain. They can breed quickly
3. Contrast knock-in and knock-out transgenic models.
Knock-in: generating a transgenic model expressing a gene that is not
normally present in the animal genome (gene added)
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Knock out: generating a transgenic model which lacks the gene (gene
removed)
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4. What are conditional and inducible transgenic models?
Conditional transgenic models: limit cell deletion to only one cell type
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Inducible transgenic models: a knockout that is activated by a specific
agent being present, without the agent, there is no knockout
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5. What are some problems with transgenic models?
The gene modification in transgenic models is non-reversible
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Deleting a gene may pose a significant stress to a system that results in
compensatory response
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Deleting certain genes can be fatal or result in severe developmental
abnormities
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6. Give examples of electrophysiological techniques and their uses.
Whole cell patch clamp -study individual cells
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Local field potentials -study large group of cells all at once
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7. What is a lesion study? Give examples. Why do we do lesion studies?
A lesion study is examine behavior changes in individuals with brain injuries
Phineas Gage -damage to frontal cortex, associated with pronounced
changes in behavior (impulsivity, profanity, social impairments)
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H.M. - hippocampus was surgically removed, afterwards, he had
anterograde amnesia
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8. What methods do we have available to study the function of specific brain areas?
Why would we bother studying just one brain area?
Lesion, pharmalogically manipulation, electrically manipulation,
optogenetics and chemogenetics. We study just on brain area in order to
determine its specific function
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9. Explain optogenetics. What are some advantages and disadvantages?
Optogenetics: a biological techniques that allows the research to modulate
the activity of targeted neurons using light
Advantage: specificity and precise-timing
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Disadvantage: technical hurdles, time and cost.
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10.Explain chemogenetics. What are some advantages and disadvantages?
Chemogenetics: permits control of neurons with drugs and involves
DREADD (designer receptor exclusively activated by designer drug)
Advantage: CNO, bidirectional control: one activation & one inhibition
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Disadvantage: not specific, other agents are founded to affect these
receptors such as clozapine / temporal resolution, don't know how
long will drugs take to work
○
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11.What is electroencephalography? Why is it useful?
Electroencephalography (EEG) involves the placement of electrodes over a
cortical column in order to measure electrical activity of the brain
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Useful because we can gain insight the areas which may be activated during
a given behavior
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Good temporal resolution / poor spatial resolution
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12.What is positron emission topography? Why it is useful?
Positron emission topography (PET) injects synthetic radiotracer into
patient and uses specialized equipment to measure to signal that the
radiotracer generates
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PET scan is useful for spatial resolution
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13.What is functional magnetic resonance imaging? Why is it useful? Why do we
have to be careful about how we interpret fMRI scans?
Functional magnetic resonance imaging (fMRI) uses properties of MRI and
blood oxygenation level dependent contract in order to image the brain
over time because oxygenated and deoxygenated blood has different
magnetic properties.
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It is useful because it also gives us the functional info of the brain
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We have to be careful with reverse inference from fMRI. Just because one
region is active (activated by function A) doesn't mean function A is
occurring.
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14.Why are single cell recordings in humans so rare?
Single cell recordings in humans are rare because it's is too invasive
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15.What is repetitive transcranial magnetic stimulation (rTMS)?
Repetitive transcranial magnetic stimulation (rTMS) is a technique wherein
neuronal activity is manipulated by magnetic field and activity is being
observed (may be used in depression)
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16.What is electrical brain mapping?
Electrical brain mapping involved electrical stimulation of brain areas in
order to determine functioning of brain areas
Cortical maps
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17.Contrast all techniques in terms of spatial and temporal resolution.
EEG & MEG have great temporal / bad spatial
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fMRI has good temporal / good spatial
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PET has bad temporal / good spatial
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Brain lesions has bad temporal / good spatial
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Single unit recordings & Patch clamp have good temporal / good spatial for
small units
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Study notes 11
Saturday, April 7, 2018
1:54 PM
Document Summary
An animal model (animal studies) is study conducted on animal. We prefer mice because they have similar genome structure and gene number to human. We strongly prefer them for transgenic models because they are cheap and easy to maintain. They can breed quickly: contrast knock-in and knock-out transgenic models. Knock-in: generating a transgenic model expressing a gene that is not normally present in the animal genome (gene added) Conditional transgenic models: limit cell deletion to only one cell type. The gene modification in transgenic models is non-reversible. Deleting a gene may pose a significant stress to a system that results in compensatory response. Deleting certain genes can be fatal or result in severe developmental abnormities: give examples of electrophysiological techniques and their uses. Whole cell patch clamp - study individual cells. A lesion study is examine behavior changes in individuals with brain injuries.
