Kafli 5 : Research

Kafli 5 : Research

1. Fixative

   • A chemical such as formalin; used to prepare and preserve body tissue.
   • Formalin
     • The aqueous solution of formaldehyde gas; the most commonly used tissue fixative.
   • Perfusion
     • The process by which an animal's blood is replaced by a fluid such as a saline solution or a fixative in preparing the brain for histological examination.

2. Labeling & Tracing

   • Histological Methods
     • Immunocytochemical Method
       • A histological method that uses radioactive antibodies or antibodies bound with a dye molecule to indicate the presence of particular proteins of peptides.
     • Anterograde Labeling Method
       • A 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; a 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.
     • Retrograde Labeling Method
       • A histological method that labels cell bodies that give rise to the terminal buttons that form synapses with cells in a particular region.
       • Fluorogold
         • A dye that serves as a retrograde label; taken up by terminal buttons and carried back to the cell bodies.
   • Pseudorabies Virus
     • A weakened form of a pig herpes virus used for retrograde transneuronal tracing, which labels a series of neurons that are interconnected synaptically.
   • Herpes Simplex Virus
     • A form of herpes virus used for anterograde transneuronal tracing, which labels a series of neurons that are interconnected synaptically.

3. Analyzing

   • Microscopes
     • Transmission Electron Microscope
       • A microscope that passes a focused beam of electrons through thin slices of tissue to reveal extremely small details.
       • Microtome
         • An instrument that produces very thin slices of body tissue.
     • Scanning Electron Microscope
       • A microscope that provides three-dimensional information about the shape of the surface of a small object by sanding the object with a thin beam of electrons.
     • Confoccal Laser Scanning Microscope
       • A 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.
   • Brain Activity
     • Experimental Ablation
       • The removal or 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 Study
         • A synonum for experimental ablation.
       • Excitotoxic lesion
         • A brain lesion produced by intracerebral injection of an excitatory amino acid, such as kainic acid.
       • Sham Lesion
         • A 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 a stereotaxic apparatus to position an electrode or cannula in a specified position of the brain.
       • Stereotaxic Atlas
         • A collection of drawings of sections of the brain of a particular animal with measurements that provide coordinates for stereotaxic surgery.
         • Bregma
           • The junction of the sagittal and coronal sutures of the skull; often used as a preference point for stereotaxic brain surgery.
       • Stereotaxic Apparatus
         • A device that permits a surgeon to position an electrode or cannula into a specific part of the brain.
     • Electroencephalogram (EEG)
       • An electrical brain potential recorded by placing electrodes on the scalp.
     • Positron Emission Tomography (PET)
       • A functional imaging method that reveals the localization of a radioactive tracer in a living brain.
     • Functional Imaging
       • A computerized method of detecting metabolic or chemical changes in particular regions of the brain.
       • Functional MRI (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.
     • 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 depolarixe or hyper polarize the neurons when light of the appropriate wavelength is applied.
     • Transcranial Magnetic Stimulation (TMS)
       • Stimulation of the 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.
     • Microdialysis
       • A 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.
   • Body Activity
     • Computerized Tomography (CT)
       • The use of a device that employs a computer to analyxe data obtained by a scanning beam of X-rays to produce a two-dimensional picture of a "slice" through the body.
     • Magnetic Resonance Imaging (MRI)
       • A 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
         • An imaging method that uses a modified MRI scanner to reveal bundles of myelinated axons in the living human brain,
     • Autoradiography
       • A 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.
   • Neuron Activity
     • Microelectrode
       • A very fine electrode, generally used to record activity of individual neurons.
       • Single-Unit Recording
         • Recording of the electrical activity of a single neuron.
     • Macroelectrode
       • An electrode used to record the electrical activity of large numbers of neurons in a particular region of the brain; much larger than a microelectrode.
     • Magnetoencephalography
       • A 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.

4. 2-deoxyglucose

   • A sugar that enters cells along with glucose but is not metabolized

5. Fos

   • A protein produced in the nucleus of a neuron in reponse to synaptic stimulation.

6. Genes

   • Genome
     • The complete set of genes that compose the DNA of a particular species.
   • Allele
     • The nature of the particular sequence of base paris of DNA that constitutes a gene; for examples, the genes that code for blue or brown iris pigment are different alleles of a particular gene.
   • Targeted Mutation
     • A mutated gene ("knockout gene")produced in the laboratory and inserted into the chromosomes of mice; fails to froduce 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.