Chapter 7 - The Methods and Ethics of Research

Theory

An integration and interpretation of diverse observations in an attempt to explain a phenomenon

Experimental Study

A study in which there is a manipulation of an independent variable to produce change in the dependent variable

Correlational Study

A study that involves the observation of whether two variables related

• no manipulation

Golgi Stain

A staining technique in which about 5% of neurons on a slide are randomly stained

Myelin Stain

A staining technique in which the fatty myelin sheath surrounding axons take up a stain

Nissl Stain

A staining technique that identifies cell bodies of neurons

Retrograde Stains

A staining technique in which the stain is taken up by neuron terminals and transported up the axons to cell bodies

Autoradiography

An imaging technique that stains and reveals which neurons are active

• a CT scan for neurons

Immunocytochemistry

An imaging technique that uses antibodies attached to a dye to identify cell components (proteins

• an “after-death” fMRI

In situ Hybridization

A construction of DNA strands which complement and pair with an mRNA strand

mRNA

A copy of one DNA strand carried from the cell nucleus into the cytoplasm

Transmission Electron Microscope (TEM)

An electron microscope that passes beams of electrons through thin slices of tissue

• up to 50 million times magnification

Scanning Electron Microscope (SEM)

An electron microscope in which beams of electrons induces the specimen to emit electrons

• up to 2 to 3 million times magnification

• produces a 3D image

Stereotaxic Instrument

A device allowing precise positioning of a probe in the brain

• like a cage that holds the head in a specific, fixed, position to get to a specific target

• psychosurgery, neurosurgery

• used for animal neuroresearch

Optogenetic Techniques

A brain manipulation technique in which light-sensitive channels can be inserted in specific types of neurons, and cells are stimulated by shining light

Microdialysis

A brain measuring technique that involves taking a sample of brain liquid and studying what’s in it

• cannulation (tube inserted into the brain)

Ablation

A surgical removal of brain tissue

• used for large areas and often imprecise

Lesioning

A surgical damaging of neural tissue

• more precise and sometimes reversible

Electroencephalogram (EEG)

An electronic amplifier that detects electrical activity of all neurons between two electrodes

• electrode hat

Transcranial Magnetic Stimulation (TMS)

A noninvasive brain manipulation technique that uses a magnet coil to induce a voltage

Computed Tomography (CT)

A brain imaging technique that produces a series of x-rays, then composite them into a 3D image

• purely structural

Magnetic Resonance Imaging (MRI)

A brain imaging technique that measures radio-frequency waves emitted by hydrogen atoms exposed to a magnetic field

Diffusion Tensor Imaging (DTI)

An MRI variant measuring the movement of water molecules

Positron Emission Tomography (PET)

A brain imaging technique that involves the observation of brain regions through a radioactive substance injected into bloodstream

Functional Magnetic Resonance Imaging (fMRI)

A brain imaging technique that detects increases in blood flow and oxygen usage

• good spatial resolution

Family Study

A study that determines how a characteristic is shared among relatives

Twin Study

A study that assesses how similar twins are compared to each other and nontwin or fraternal twin siblings

Concordance Rate

The frequency with which relatives are alike in a characteristic

Genetic Engineering

A manipulation in an organism’s genes and DNA

Knockout Technique

A genetic engineering technique in which a nonfunctioning mutation is introduce into a gene then transferred to the embryos

• replacing/removing a working version of a gene with non-working version

Knockdown Technique

A genetic engineering technique in which a gene is silenced by interfering with its expression

• turning it off

Antisense RNA

A complementary strand of RNA which binds to mRNA to block gene expression

Gene Transfer

A genetic engineering technique in which a gene from another organism is inserted into recipient cells

Gene Therapy

A genetic engineering technique in which disorders are treated by manipulating genes

Vector

A DNA molecule used as a vehicle to carry genes into the body