5 Research Methods Flashcards
Lesion study
experimental ablation
Experimental ablation
The removal or destruction of a portion of the brain laboratory animal; presumably the functions that can no longer be performed are ones the region previously controlled.
Excitotoxic lesion
brain lesion produce by intracerebral injection of an excitatory amino acid, such as kainic acid.
Sham lesion
Placebo procedure that duplicates all the steps of producing a brain lesion except the one that actually causes the brain damage.
Stereotaxic surgery
Brain surgery using stereotaxic apparatus to position and electrode or cannula in a specified position of the brain.
Bregma
Junction of the sagittal and coronal sutures of the skull; often used as a reference point for stereotaxic brain surgery.
Stereotaxic atlas
Collection of drawings of sections of the brain of a particular animal with measurements that provide coordinates for stereotaxic surgery.
Stereotaxic apparatus
Device that permits the surgeon to position and electrode or cannula into a specific part of the brain.
Fixative
Chemical such as formalin; used to prepare and preserve body tissue.
Formalin
Aqueous solution of formaldehyde gas; the most commonly used tissue fixative.
Perfusion
Process by which an animal’s blood is replaced by a fluid such as saline solution or fixative in preparing the brain for histological examination.
Microtome
Instrument that produces very thin slices of body tissues.
Transmission electron microscope
Microscope that passes a focused beam of electrons through thin slices of tissue to reveal extremely small details.
Scanning electron microscope
Microscope that provides three-dimensional information about the shape of the surface of a small object by scanning the object with a sin beam of electrons.
Confocal laser scanning microscope
Microscope that provides high-resolution images of various depths of thick tissue that contains fluorescent molecules by scanning the tissue with light from a laser beam.
Anterograde labeling method
Histological method that labels the axons and terminal buttons of neurons whose cell bodies are located in a particular region.
PHA-L
Phaseolus vulgaris leukoagglutinin; protein derived from kidney beans and used as an anterograde tracer; taken up by dendrites and cell bodies and carried to the ends of the axons.
Immunocytochemical method
Histological method that uses radioactive antibodies or antibodies bound with a dye molecule to indicate the presence of particular proteins of peptides.
Retrograde labeling method
Histological method that label cell bodies that give rise to the terminal buttons that form synapses with cells in a particular region.
Fluorogold
Dye that serves as a retrograde label; taken up by terminal buttons and carried back to the cell bodies.
Pseudorabies virus
Weakened form of pig herpesvirus use for retrograde transneuronal tracing, which labels a series of neurons that are interconnected synaptically.
Herpes simplex virus
Form of herpesvirus used for anterograde transneuronal tracing, which labels a series of neurons that are interconnected synaptically.
Computerized tomography (CT)
Use of a device that employs a computer to analyze data obtained by scanning beam of x-rays to produce two-dimensional picture of a “slice” through the body.
Magnetic resonance imaging (MRI)
Technique whereby the interior of the body can be accurately imaged; involves the interaction between radio waves and a strong magnetic field.
Diffusion tensor imaging (DTI)
Imaging method that uses modified MRI scanner to reveal bundles of myelinated axons in the living human brain.
Microelectrode
Very fine electrode, generally used to record activity of individual neurons.
Single-unit recording
Recording of the electrical activity of a single neuron.
Macroelectrode
Electrode used to record the electrical activity of large numbers of neurons in a particular region of the brain; much larger than a microelectrode.
Electroencephalogram (EEG)
Electrical brain potential recorded by placing the electrodes on the scalp.
Magnetoencephalography
Procedure that detects groups of synchronously activated neurons by means of the magnetic field induced by their electrical activity; uses an array of superconducting quantum interference devices, or SQUIDs.
2-deoxyglucose (2-DG)
Sugar that enters cells along with glucose but is not metabolized.
Autoradiography
Procedure that locates radioactive substances in a slice of tissue; the radiation exposes a photographic emulsion or a piece of film that covers the tissue.
Fos
Protein produced in the nucleus of a neuron in response to synaptic stimulation.
Functional imaging
Computerized method of detecting metabolic or chemical changes in particular regions of the brain.
Positron emission tomography (PET)
Functional imaging method that reveals the location of radioactive tracer in a living brain.
Functional MRI (fMRI)
Functional imaging method; modification of the MRI procedure that permits the measurement of regional metabolism in the brain, usually by detecting changes in blood oxygen level.
Optogenetic method
The use of a genetically modified virus to insert light-sensitive ion channels into the membrane of particular neurons in the brain; can depolarize or hyperpolarized the neurons when light of the appropriate wavelength is applied.
Transcranial magnetic stimulation (TMS)
Stimulation of the cerebral cortex by means of magnetic field 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.
Microdialysis
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.
Genome
Complete set of genes that compose the DNA of a particular species.
Allele
Nature of the particular sequence of base pairs of DNA that constitutes a gene; for example the genes that code for blue or brown iris pigment are different alleles of a particular gene.
Targeted mutation
Mutated gene (also called a “knock out gene”) produced in the laboratory and inserted in the chromosomes of mice; fails to produce a functional protein.
Antisense oligonucleotide
Modified strand of RNA or DNA that binds with a specific molecule of mRNA and prevents it from producing its protein.
