Methods and Strategies of Research

Name: Methods and Strategies of Research
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Description: Methods and Strategies of Research

Methods and Strategies of Research
Chapter 5 Methods and Strategies of Research This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network preparation of any derivative work, including the extraction, in whole or in part, of any images any rental, lease or lending of the program. Copyright © 2008 Pearson Allyn & Bacon Inc.

Chapter 5 Outline Experimental Ablation
Recording and Stimulating Neural Activity Neurochemical Methods Genetic Methods Copyright © 2008 Pearson Allyn & Bacon Inc.

Experimental Ablation
Evaluating the behavioral effects of brain damage Experimental ablation (one of the oldest techniques in neuroscience) The _____________________________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 synonym for experimental ablation. Lesions __________________caused by strokes or other impairments to the CNS, and they provide an experimental platform for developing treatments. Copyright © 2008 Pearson Allyn & Bacon Inc.

Experimental Ablation Producing brain lesions Excitotoxic lesion
A brain lesion produced by intracerebral injection of an __________________, such as kainic acid. (Kainic acid stimulate glutamate receptors) ____________lesion A placebo procedure that duplicates all the steps of producing a brain lesion except for the one that actually causes the brain damage. Copyright © 2008 Pearson Allyn & Bacon Inc.

Experimental Ablation Stereotaxic surgery
Brain surgery using a stereotaxic apparatus to __________an electrode or cannula in a __________position of the brain. Bregma The junction of the sagittal and coronal sutures of the skull, often used as a ___________________for stereotaxic brain surgery. Copyright © 2008 Pearson Allyn & Bacon Inc.

Experimental Ablation The stereotaxic atlas Stereotaxic atlas
A collection of drawings of sections of the brain of a particular animal with measurements that provide ________________for the stereotaxic surgery. Copyright © 2008 Pearson Allyn & Bacon Inc.

Experimental Ablation The stereotaxic apparatus Stereotaxic apparatus
A device that permits a surgeon to position an electrode or cannula into a specific part of the brain. Copyright © 2008 Pearson Allyn & Bacon Inc.

Fixation and sectioning Fixative
Histological Methods Fixation and sectioning Fixative A chemical such as formalin; used to prepare and _____________ body tissue. Formalin The aqueous solution of formaldehyde gas; the most commonly used tissue fixative. Halts autolysis (self dissolving) Hardens soft tissue Kills microorganisms Copyright © 2008 Pearson Allyn & Bacon Inc.

Fixation and sectioning Microtome
Histological Methods Fixation and sectioning Microtome An instrument that produces very ___________of body tissue. 1 to 80 micrometer thick (1-millionth of a meter). Different ____________ are needed to make different cellular structures visible for light or electron microscopy. Copyright © 2008 Pearson Allyn & Bacon Inc.

Electron microscopy (electron beam)
Histological Methods Electron microscopy (electron beam) ________________em is used for magnification above 1500 x (the limit for light microscopy) ______________ electron microscope A microscope that provides three-dimensional information about the shape of the surface of a small object. Copyright © 2008 Pearson Allyn & Bacon Inc.

Tracing Neural Connections Tracing efferent axons
(VMH neurons do not connect to muscles directly, but the pathway of CNS connections can be traced) 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 ____________and carried to the ___________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Tracing Neural Connections Tracing efferent axons
Immunocytochemical method A histological method that uses ________ antibodies or antibodies bound with a dye molecule to indicate the presence of particular proteins of peptides. Copyright © 2008 Pearson Allyn & Bacon Inc.

VMH neurons project to the periaqueductal gray matter (PGA).

Tracing Neural Connections Tracing afferent 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. The chemical is carried from the _________________________________. Fluorogold A dye that serves as a retrograde label that is taken up by the terminal buttons and then carried back to the cell bodies. (Medial amygdala provides input to VMH) Copyright © 2008 Pearson Allyn & Bacon Inc.

Tracing Neural Connections Tracing afferent axons
Anterograde and retrograde methods label just a single link in a chain of neurons. _______________ methods may trace several links in the chain, and help establish a wiring diagram. Pseudorabies virus A weakened form of a pig virus; used for transneuronal tracing which labels a series of neurons that are interconnected synaptically. The virus ___________________________ in the chain. This method permits anterograde and retrograde directions. Copyright © 2008 Pearson Allyn & Bacon Inc.

Study of the Living Human Brain Computerized tomography (CT)
The use of a device that employs a computer to analyze data obtained by a scanning beam of X-rays to produce a _________________________________________________________________________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Damaged area from a stroke

Study of the Living Human Brain Magnetic resonance imaging (MRI)
A technique whereby the interior of the body can be accurately imaged; involves the interaction between _______________________________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Recording and Stimulating Neural Activity
Recordings with microelectrodes 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. Copyright © 2008 Pearson Allyn & Bacon Inc.

Recording and Stimulating Neural Activity
Recording with macroelectrodes Macroelectrode An electrode used to record the electrical activity of _____________________in a particular region of the brain; much larger than a ______________. Electroencephalogram (EEG) An electrical brain potential recorded by placing electrodes on or in the scalp. Copyright © 2008 Pearson Allyn & Bacon Inc.

Recording and Stimulating Neural Activity Magnetoencephalography
A procedure that detects groups of ________ activated neurons by means of the magnetic field induced by their electrical activity. This procedure uses an array of superconducting quantum interference devices, or ______________. Copyright © 2008 Pearson Allyn & Bacon Inc.

Recording the Brain’s Metabolic and Synaptic Activity
2-deoxyglucose (2-DG) A sugar that enters cells along with glucose but is not metabolized. _______ rates of metabolic activity are revealed by the increased up take of 2-DG. 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. Copyright © 2008 Pearson Allyn & Bacon Inc.

High level of activity in the hypothalamus

Recording the Brain’s Metabolic and Synaptic Activity
Fos A protein produced in the nucleus of a neuron in response to synaptic stimulation. Positron emission tomography (_____) The use of a device that reveals the localization of a radioactive tracer in a living brain. Functional MRI (______) A modification of the MRI procedure that permits the measurement of regional metabolism in the brain. Copyright © 2008 Pearson Allyn & Bacon Inc.

FOS stain indicates the neurons activated during copulation (rat forebrain).

Thus they reveal more detailed information than PET scans.
Functional MRI scans have higher ____________ than PET scans, and can be acquired at a faster rate. Thus they reveal more detailed information than PET scans. Copyright © 2008 Pearson Allyn & Bacon Inc.

Measuring the Brain’s Secretions 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. A technique used to measure secretions of ____________________________________. Copyright © 2008 Pearson Allyn & Bacon Inc.

The transplant greated diminished the symptoms of Parkinson’s disease.
In humans fetal dopaminergic neurons have been ___________ in the basal ganglia of some Parkinson’s patients. The transplant greated diminished the symptoms of Parkinson’s disease. Copyright © 2008 Pearson Allyn & Bacon Inc.

More dopamine secreted after the implant.

Chemicals are infused to stimulate the brain.

Behavioral Effects of Electrical Stimulation
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. TMS has been used to disrupt the activity of some over active brain centers associated with depression. Copyright © 2008 Pearson Allyn & Bacon Inc.

Neurochemical Methods Organophosphate insecticides
Human exposure to insecticides that contain acetylcholinesterase inhibitors (acetylcholine agonists) could cause intense, bizarre dreams and walking hallucination. The insecticide directly activated the neural circuits responsible for dreaming. Neurochemical methods can be used to determine the location of an enormous variety of substances in the brain. These methods can be used to localize neurotransmitters themselves, or the enzymes that produce them. Copyright © 2008 Pearson Allyn & Bacon Inc.

Rat forebrain terminal buttons that secrete vasopressin.

Choline acetyltransferase in the pons

Antisense oligonucleotide
Genetic Methods Targeted mutations A mutated gene )also called a __________________ produced in the laboratory and inserted into the chromosomes of mice; fails to produce a functional protein. Antisense oligonucleotide A modified strand of RNA or DNA that binds with a specific molecule of messenger RNA and prevents it from producing it particular protein. These methods have the potential to reduce the likelihood of some individual developing inherited disorders or some addictions. Copyright © 2008 Pearson Allyn & Bacon Inc.

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