Chapter 4: Research Techniques Flashcards
Simple Behavioral Observation
tremors, ptosis (drooping eyelids), salivation, catalepsy (sensation of movement)
Measures of Motor Activity
- identify drugs that produce sleep, sedation, loss of coordination, or drugs that stimulate activity
- open field- rodents run around open field and explore whole box
Measures of Learning and Memory
- Morris water maze
- Delayed- response test
Morris water maze
- circular pool of water made opaque by addition of milk or dye
- animals must swim until they find escape platform hidden from view just below water surface
- animals learn spatial position of platform relative to landmarks outside the pool
- depends on hippocampal memory system
Delayed- response test
- similar to evaluating working memory in humans
- a delay between stimulus presentation (food) and testing evaluates recall for the position of food
Measures of Anxiety
- Light- dark crossing
- Elevated plus-maze
- Conditioned emotional response
Light- dark crossing
- unconditioned anxiety
- animals naturally avoid brightly lit places
- L-D box has one side brightly lit and the other side is dark
- measures include number of crossings, time spent on each side, total motor activity
Elevated plus-maze
- unconditioned anxiety
- cross-shaped maze raised off the floor
- two arms are open, and two ars have enclosed sides
- antianxiety drugs increase amount of exploration of the open arms
- drugs that increase anxiety decrease exploration of open arms
Conditioned emotional responses
- presentation of a signal (a light or tone, CS) is followed by an unavoidable electric shock (US)
- after conditioning (US+CS pairing), the signal (CS) will elicit a conditioned response (CR or CER)
- conditioned freezing
- fear- potentiated startle
Measure of Depression- Like Behavior
- Forced swim test
- Sucrose preference test
Forced swim test
- behavioral despair
- animal must swim in a cylinder from which it can’t escape
- immobility reflects a lowered mood
- animal model of hopelessness
Sucrose preference test
- anhedonia, inability to derive pleasure from normally pleasurable events
- animals are given a choice of water or sucrose solution, which they normally prefer
- a variety of stressors can reduce sucrose preference
Drug Self- Administration
- an indicator of abuse potential in humans
- varying the schedule of reinforcement determines how hard an animal will work for drug
- breaking point
- also used to study withdrawal and/ or relapse
Breaking Point
point at which effort required exceeds reinforcing value- the higher the breaking point, the higher the abuse potential
Optogenetics
manipulates neural circuits using light
- can activate/ inhibit certain channels
Chemogenetics
puts in receptors to artificially activate secondary messengers
- designer receptor activated by designer drug (DReADD)
Lesioning
uses stereotaxic device to position delicate electrode deep within brain
- tissue at tip is destroyed when current goes through electrode
Neurotoxins
chemical that damages nerve cells
- can be injected via cannula (hollow tube instrument)
Microdialysis
also uses stereotaxic surgery
- lets us measure NTs released in specific brain regions while subject is engaged in behavior
In Vivo Voltametry
uses stereotaxically implanted microelectrodes to measure neurochemicals in ECF of freely moving animals
Macroelectrodes
used to activate cells at tip while changes in animal behavior is evaluated during stimulation
- can also be used to record summated electrical response in specific brain region
Microelectrode
single- unit recording of electrical into single cell
Intracellular Recording- implanting fine-tipped electrode into single cell
Extracellular Recording- measures ECF near single cell
Patch Clamp Electrophysiology
used to study function of individual ion channels
Antibody Production
protein produced by WBCs to recognize, attack and destroy antigens
- researchers use antibodies that bind to specific proteins to locate then in brain
Immunocytochemistry (ICC)
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Immunocytochemistry (ICC)
- Brain is fixed (hardened) using preservative
- Tissue slices are out and incubated with antibody in solution
- Antibody attaches to antigen
- Antibody is tagged so antigen contain cells can be visualized
*more selective than autoradiography because antibodies are used
[…] uses antibodies to detect specific proteins in tissue rather than slice
Western blot uses antibodies to detect specific proteins in tissue rather than slice
Radioimmunoassay
based on competitive binding of antibody to antigen
- highly specific and highly sensitive
Enzyme- Linked Immunosorbent Assay (ELISA)
relies on enzyme that acts (instead of radioactivity detection) to form a colored product
In Situ Hybridization (ISH)
used to locate cells in tissue slices that make particular protein/ peptide
- useful for detecting specific mRNA responsible for directing the production of many proteins
DNA Microassays
1. 2. 3. 4. 5.
DNA Microassays- able to examine all genes simultaneously
- Tissue to be evaluated is dissected
- mRNAs are isolated and labeled
- Hybridize to large number of immobilized DNA molecules on chip
- Scanner evaluates extent of hybridization
- Computer analysis is used to identify patterns of gene activity
Computerized Tomography (CT)
increases resolution of image and provides image in 3D
Magnetic Resonance Imaging (MRI)
measures distinct waves that different atoms emit when placed in strong magnetic field and activated by radio-frequency waves
Magnetic Resonance Spectroscopy (MRS)
uses MRI- generated data to calculate concentration of brain chemicals and metabolic changes
Diffusion Tensor Imaging (DTI)
scans microscopic 3D movement of water in neural tissue
- SPECT is similar, but radiolabeled probes are cheaper
Functional MRI (fMRI)
can detect increases in blood oxygenation due to cell activity
- looks at hemoglobin specifically
Resting- State fMRI (rs-fMRI)
used to look at connectivity among brain regions when individual is awake, but not doing anything
Pharmacological MRI (phMRI)
look at drug mechanisms by analyzing changes in brain function following drug administration and identifies location of drug action in CNS
Electroencephalography (EEG)
electrodes are used to record electrical activity
reflects sum of electrical events of populations of neurons
Quantitative EEG (qEEG)
analysis of large amounts of data collected with EEG
Event- Related Potentials (ERP)
changes in response to momentary sensory stimulation
