Brain And Behavior: Study Questions For Chapter 5

Front 1

What is an experimental ablation? What is a lesion?

Back 1

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

Front 2

What are the various ways of producing a lesion? What are sham lesions?

Back 2

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

Front 3

What is a included in a stereotaxic surgery?

Back 3

Brain surgery using a stereotaxic apparatus to position an electrode or cannula in a specific portion of the brain

Front 4

What is a stereotaxic atlas? How is it used in surgery?

Back 4

Pictures of the brain with coordinates to neural structure in relation to the bregma

Front 5

What is a bregma?

Back 5

Junction of sagittal coronal sutures of the skull

Front 6

What is a stereotaxic apparatus?

Back 6

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

Front 7

What procedures are included (comprise) the histological procedures (methods)?

Back 7

Histological methods: Fixing, slicing, staining, and examining portions of the brain to verify it is the precise location of brain damage

Front 8

Define: Fixative, perfusion, sectioning, staining

Back 8

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

Front 9

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?

Back 9

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

Front 10

What method is used to trace efferent axons?

Back 10

Stimulation of VMH to watch how it effects other parts of the brain; anterograde labeling

Front 11

What is the anterograde labeling method?

Back 11

Histological method that traces efferent axons; labels the axons and terminal buttons of neurons whose cell bodies are located in a particular region

Front 12

What chemical is used to identify efferent axons?

Back 12

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

Front 13

What are the immunocytochemical methods? What chemical is located by immunocytochemical techniques?

Back 13

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

Front 14

What method is used to trace afferent axons? What is the retrograde labeling method?

Back 14

Traces afferent axons; histological method that labels cell bodies that give rise to TBs that form synapses within cells in a particular region

Front 15

What is computerized tomography (CT or CT scan)?

Back 15

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

Front 16

What is magnetic resonance imaging (MRI)?

Back 16

Interior of the body can be accurately images through interaction between radio and magnetic ways

Front 17

What is diffusion tenser imaging?

Back 17

Imaging method that uses modified MRI scanner to reveal bundles of myelinated axons in the human brain

Front 18

What is used to record the brain's electrical (neural) activity?

Back 18

EEG, MEG, fMRI

Front 19

What are microelectrodes?

Back 19

Records the brains' electrical activity; very fine electrodes used to record activity of individual neurons

Front 20

What is single-unit recording? How is it different from the other methods?

Back 20

Recording electrical activity of a single neuron; more invasive than other methods

Front 21

What are macroelectrodes? When are they used (vs. microelectrodes)? What do they record?

Back 21

Records brains' electrical activity in clusters of neurons in a particular region of the brain, much larger than microelectrodes

Front 22

What are electroencephalograms?

Back 22

An electric brain potential recorded by placing electrodes on the scalp

Front 23

What is magnetoencephalography? How is it different from the other methods? What are SQUIDS? What do they measure?

Back 23

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

Front 24

What chemical is used to measure metabolic activity?

Back 24

2-deoxyglucose (2-DG): Used to measure metabolic activity; sugar that enters cells along with glucose, but is not metabolized

Front 25

Describe method of autoradiography?

Back 25

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

Front 26

What is positron emission tomography (PET)?

Back 26

Functional imaging method that reveals the localization of a radioactive tracer

Front 27

What is a functional magnetic resonance imaging (fMRI)?

Back 27

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

Front 28

How can you stimulate neural activity?

Back 28

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

Front 29

What are optogenetic methods? What can they measure?

Back 29

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

Front 30

What is transcranial magnetic stimulation (TMS)?

Back 30

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

Front 31

What are two basic ways of localizing neurochemicals in the brain?

Back 31

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

Front 32

What methods are used to localize receptors?

Back 32

Microdialysis, afferent/efferent tracing

Front 33

What is microdialysis? When is it used?

Back 33

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

Front 34

What are the various genetic methods? What is a value of each?

Back 34

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

Front 35

What are targeted mutations? What is another name for these genes?

Back 35

Mutated gene (also called a "knockout gene") produced in the laboratory and inserted into the chromosome of mice; fails to produce a functional protein

Front 36

What are antisense oligonucleotides?

Back 36

Modified strand of RNA or DNA that binds with a specific molecule of mRNA and prevents it from producing its protein