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36 Cards in this Set
- Front
- Back
What is an experimental ablation? What is a lesion? |
Experimental ablation: Removal/destruction of a portion of the brain of a laboratory animal; presumably the functions that can no longer be performed are the ones the region previously controlled Lesion: Wound, injury |
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What are the various ways of producing a lesion? What are sham lesions? |
Lesions are produced by passing an electrical current through an insulated, stainless-steel wire, the lesion-making device turns on and kills the brain tissue via heat. Sham lesions: Duplicates all the steps of producing a brain lesion except for the one that actually causes damage |
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What is a included in a stereotaxic surgery? |
Brain surgery using a stereotaxic apparatus to position an electrode or cannula in a specific portion of the brain |
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What is a stereotaxic atlas? How is it used in surgery? |
Pictures of the brain with coordinates to neural structure in relation to the bregma |
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What is a bregma? |
Junction of sagittal coronal sutures of the skull |
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What is a stereotaxic apparatus? |
Has a holder that fixes the animal's head in position, a carrier that moves an electrode or cannula through measured distance in 3-D |
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What procedures are included (comprise) the histological procedures (methods)? |
Histological methods: Fixing, slicing, staining, and examining portions of the brain to verify it is the precise location of brain damage |
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Define: Fixative, perfusion, sectioning, staining |
Fixative: A chemical such as formalin; used to prepare and preserve brain tissue Perfusion: Process by which an animal's blood is replaced with a fluid (e.g., saline solution) or fixative in preparing within and out of the cells Sectioning: Slicing brain tissue Staining: Allows fine details to be revealed under a microscope; allows researchers to identify specific substances within and out of the cells |
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What is electron microscopy? How is it different from the other methods? What is a transmission electron microscope? What is a scanning electron microscope? What is a confocal laser scanning microscope? |
Electron microscopy: In order to see detailed structures of cells, a beam of electrons is passed through a slice of brain tissue to be examined; provides information of structural details on the order of a few tens of nanometers Transmission electron microscopes: Passes a focus to electrons through thin slices of tissue to see extreme details of brain Scanning electron microscope: Provides 3D information about the shape of a surface of a small object by scanning the object with a beam of electrons Confocal laser scanning microscope: Provides high-resolution images of various depths of thick tissue that contains fluorescent molecules by scanning the tissue with light from a laser beam |
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What method is used to trace efferent axons? |
Stimulation of VMH to watch how it effects other parts of the brain; anterograde labeling |
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What is the anterograde labeling method? |
Histological method that traces efferent axons; labels the axons and terminal buttons of neurons whose cell bodies are located in a particular region |
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What chemical is used to identify efferent axons? |
PHA-L: Protein-founded kidney beans and used as an anterograde tracer; taken up by dendrites and cell bodies and carried to the ends of the axon to trace efferent axons |
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What are the immunocytochemical methods? What chemical is located by immunocytochemical techniques? |
Histological method that uses radioactive antibodies bound with a dye molecule to indicate presence of particular protein peptides; antigens and antibodies are chemicals located by these techniques |
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What method is used to trace afferent axons? What is the retrograde labeling method? |
Traces afferent axons; histological method that labels cell bodies that give rise to TBs that form synapses within cells in a particular region |
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What is computerized tomography (CT or CT scan)? |
Use of a device that employs a computer to analyze data obtained by a scanning beam of X-rays to produce two-dimensional picture of a "slice" through the body |
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What is magnetic resonance imaging (MRI)? |
Interior of the body can be accurately images through interaction between radio and magnetic ways |
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What is diffusion tenser imaging? |
Imaging method that uses modified MRI scanner to reveal bundles of myelinated axons in the human brain |
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What is used to record the brain's electrical (neural) activity? |
EEG, MEG, fMRI |
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What are microelectrodes? |
Records the brains' electrical activity; very fine electrodes used to record activity of individual neurons |
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What is single-unit recording? How is it different from the other methods? |
Recording electrical activity of a single neuron; more invasive than other methods |
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What are macroelectrodes? When are they used (vs. microelectrodes)? What do they record? |
Records brains' electrical activity in clusters of neurons in a particular region of the brain, much larger than microelectrodes |
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What are electroencephalograms? |
An electric brain potential recorded by placing electrodes on the scalp |
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What is magnetoencephalography? How is it different from the other methods? What are SQUIDS? What do they measure? |
Procedure that detects groups of synchronously-activated neurons by means of the magnetic field produced by electrical activity; cruder image is produced at a relatively faster rate than MRI. SQUIDS: Super-conducting quantum interfering device; measures magnetic feels ~1 billionth of Earth's magnetic field |
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What chemical is used to measure metabolic activity? |
2-deoxyglucose (2-DG): Used to measure metabolic activity; sugar that enters cells along with glucose, but is not metabolized |
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Describe method of autoradiography? |
Procedure that locates radioactive substances in a slice of tissue 1. Radiation exposes a photogenic emulsion of piece of film that covers the tissue 2. Sections of the brain are mounted onto microscope slides 3. Slides are taken into a darkroom, where they are coated with a photographic emulsion (substance found on photographic film) 4. Several weeks later, slides are developed; molecules of radioactive 2-DG show themselves as spots of silver grains in the developed emulsion because the radioactivity exposes the emulsion, just as x-rays or light wouldW |
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What is positron emission tomography (PET)? |
Functional imaging method that reveals the localization of a radioactive tracer |
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What is a functional magnetic resonance imaging (fMRI)? |
A functional imaging method; a modification of the MRI procedure that permits the measurement of regional metabolism in the brain, usually by detecting changes in blood oxygen levels |
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How can you stimulate neural activity? |
You can stimulate neural activity electrically or chemically. Electrically: Passing an electrical current through a wire inserted into the brain Chemically: Usually accompanied by injecting a small amount of an excitatory amino acid into brain |
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What are optogenetic methods? What can they measure? |
Use of genetically-modified virus to insert light-sensitive ion-channels into the membrane of particular neurons in the brain; can depolarize or hyperpolarize the neurons when the light of appropriate wavelength is applied Measures neural behavior |
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What is transcranial magnetic stimulation (TMS)? |
Stimulation of cerebral cortex by means of magnetic fields produced by passing pulses of electricity through a coil of wire placed next to the skull; interferes with the functions of the brain region that is stimulated |
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What are two basic ways of localizing neurochemicals in the brain? |
Autoradiography by revealing the distribution of a radioactive ligand to which the tissue has been exposed Immunocytochemistry that detects the presence of the receptors (proteins) themselves |
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What methods are used to localize receptors? |
Microdialysis, afferent/efferent tracing |
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What is microdialysis? When is it used? |
Procedure for analyzing chemicals present in the interstitial fluid through a small piece of tubing made of a semipermeable membrane that is implanted in the brain; used to measure the amount of dopamine in particular regions of the brain |
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What are the various genetic methods? What is a value of each? |
Twin studies: Comparison of concordance rates of monozygotic and dizygotic twins estimates heritability of traits Adoption studies: Similarity of offspring and adoptive and biological parents estimates heritability of traits Targeted mutations: Inactivation, insertion, or increased expression of a gene Genomic studies: The complete set of genes that compose the DNA of a particular species Antisense oligonucleotides: Bind with the message RNA, prevents synthesis of protein |
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What are targeted mutations? What is another name for these genes? |
Mutated gene (also called a "knockout gene") produced in the laboratory and inserted into the chromosome of mice; fails to produce a functional protein |
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What are antisense oligonucleotides? |
Modified strand of RNA or DNA that binds with a specific molecule of mRNA and prevents it from producing its protein |