unit 7

Question 1

where behavioral methods are used in biomedical research

Answer 1

Drug development
Therapeutic testing
Animal models of disease
Behavioral phenotyping
As tools for analyzing behavior

Question 2

tools for analyzing behavior

Answer 2

behaviors that rely on learning, memory, and cognition are all examples of areas where behavioral studies have provided important insights.

Question 3

drug development and therapeutic testing

Answer 3

new pharmaceutical compounds must be tested for effects on animals first to determine if further development is likely to be worthwhile. This testing involves the effects of the drugs on animal behavior. This includes behavioral testing of offspring of mothers dosed with drugs during pregnancy.

Question 4

behavioral phenotyping

Answer 4

a behavioral phenotype is the pattern of behavior that is associated with biological disorders. For example, you might ask if an animal exhibits the kind of behavior you expect to see in a human with schizophrenia. Perceptual, motor, cognitive and social behaviors are included. Manipulating genes, gene expression to give different phenotypes.

Question 5

animal models of disease

Answer 5

behavioral studies can be useful for studying the mechanisms of disease and determining the origins and progression of diseases.

Question 6

the uses of behavioral studies in pharmacology

Answer 6

What behavioral changes are induced by a drug?
Does a drug have therapeutic potential?
Does a drug have toxic or teratological effects?
What psychological processes are affected by a drug?

Question 7

simple classes of behavior

Answer 7

Reflexes and Locomotor Responses
 Innate
 Stereotyped pattern
 Lack spontaneity (stimulus bound)
Instinctive and Motivated Behaviors
 More complex in form than reflexes and sequenced
 Fixed action patterns
 Appetitive and consumatory phases
 Do not require prior experience
 Modifiable

Question 8

complex classes of behavior

Answer 8

Learned Behavioral Changes
 Sensitization
 Classical conditioning
 Instrumental conditioning
 Tests of cognitive function

Question 9

reflexes and locomotor responses

Answer 9

are behaviors that the animals are born capable of doing, i.e., they are innate. They are very stereotypical meaning the behavioral response looks very much the same each time the animal does it. We also say the responses are stimulus bound– the animal doesn’t spontaneously make the behavior, rather, the behavior is made in response to the presence of a stimulus.

Question 10

instinctive and motivated behaviors are more complex than reflexes and involve

Answer 10

sequences of actions, sometimes put together in fixed action patterns: A fixed action pattern is basically a sequence of behavior that cannot be changed and that once started, is carried to completion. These behaviors often have appetitive and consummatory phases in which the appetitive phase is the searching out of some stimulus and the consummatory phase is doing a characteristic pattern of behavior after acquiring the stimulus to achieve the satisfaction of a specific drive.

Question 11

complex behaviors require

Answer 11

training involving kinds of conditioning, either classical or instrumental (i.e., Pavlovian vs Skinnerian). Tests of cognitive function are placed in this category.

Question 12

tremor

Answer 12

involuntary and uncontrollable shaking of the body or body parts

Question 13

seizures

Answer 13

sudden, uncontrolled electrical disturbance in the brain which can cause changes in behavior, including tremors

Question 14

ptosis

Answer 14

a drooping of the eyelids can be a symptom of nerve/muscle problems

Question 15

salivation

Answer 15

can be an indivator of parasympathetic nervous system effects, excess salivation means the PNS activity is increased

Question 16

harderian secretion

Answer 16

involves secretions from glands in the eyes
- in rats it is an excellent indicator that the animal is subjected to one or more stressors including an illness

Question 17

defication/urination

Answer 17

can be used as indices of fear and anxiety
- the more fecal boli a rodent deficates, the more afaid he is

Question 18

grooming

Answer 18

a healthy, happy animal will groom itself, a sick, moribund animal will not

Question 19

placing response

Answer 19

a test assessing proprioceptive abilities. the first test is to lift an animal and bring the surface of a paw up to a table edge. the normal animal will position its paw onto the surface properly, if an animal cannot do this it implies that there is either a motor deficit or damage to the sensory pathway for propriception

Question 20

righting response

Answer 20

the righting reflex, is a reflex that corrects the orientation of the body when it is taken out of normal position

Question 21

cataplexy

Answer 21

a sudden and transient episode of muscle weakness

Question 22

withdrawal reflex

Answer 22

nociceptive or flexor withdrawal reflex, is a spinal reflex intended to protect the body from damaging stimuli
-This withdrawal reflex, i.e., the “tail-flick” is an example of a response, to a painful thermal stimulus. There is a heat source under the tail. As the heat increases to painful levels, the rat or mouse flicks its tail to escape the heat. An increase in the latency of the tail-flick response is a measure of the analgesic effects of a drug. The apparatus is programmed in a way that the heat turns off automatically before there is any tissue damage or harm to the animal.
- Very accurate way to measure analgesics

Question 23

locomotor responses

Answer 23

open field, running wheel, activity cages, swimming, running wheel, rotarod

Question 24

these are other simple behaviors used to assess locomotor responses

Answer 24

These tests could tell you something about:
1) motor systems and dopaminergic systems that control motor behavior in the basal ganglia
2) Psychological processes like anxiety and motivation.
3) cholinergic systems that directly affect the neuromuscular junction

Question 25

open field test

Answer 25

The open field test is a common measure of exploratory behavior, general motor activity and anxiety (i.e., fear).
Animals with low levels of anxiety are more likely to explore the central area of the open arena (far right) than animals with high levels of anxiety. Animals with high levels of anxiety will display reduced locomotion and exploration, with a preference to stay close to the walls of the open field arena (far left). It can be used to test the efficacy of anxiolytics (a medication that inhibits anxiety) and even anxiogenics (drugs that increase anxiety).

Question 26

recording the wheel-running activity of a hamster

Answer 26

The rodent Activity Wheel is a simple way to register animal physical activity in its home cage environment.
This tool is particularly relevant for research involving circadian rhythms, phenotyping and drug testing. Typically, the time and distance run on a voluntary running wheel are monitored over several days or weeks to determine whether a substance or experimental manipulation affects exercise behavior. The running wheel is commonly used in studies of obesity and energy balance as a surrogate for general activity.

Question 27

rotarod apparatus

Answer 27

-measures coordinated motor activity.
In order to stay on the rod, the mouse must walk in a direction opposite the direction of rotation.
The test measures parameters such as riding time (typically in seconds) or endurance. Because of concern for impairment in human motor behavior from the use of prescription medications, the rotarod test is frequently used in early stages of drug development to screen out drugs that might later cause subtle impairments, which might not be detected epidemiologically in a human population for a very long time.

Question 28

instinctive and motivated behaviors

Answer 28

ingestive, courtship, reproductive, parental care, social, aggression, flight (escape)
-A wide variety of motivated behaviors are used to study drug effects. These behaviors are no longer simple motor skills but are behaviors performed to satisfy physiological and reproductive needs of the animal and involve social aspects.

Question 29

recording patterns of food and water intake

Answer 29

If you are interested in obesity and weight control, you may intensely study drug effects on eating behavior itself, for example.
- Prandial drinking – taking a drink or lick of water right after eating, seen in conditioned desalivated rats (desalivated means take the salivary glands out)

Question 30

aggression

Answer 30

These are examples of discrete aggressive behaviors that can be measured. Aggressive grooming, sideways threat, boxing, attack biting and aggressive-submission. Amphetamines and anabolic steroids tend to increase this behavior.

• Resident becomes the dominant animal and the intruder becomes the submissive animal –> go through aggression rituals

Question 31

learning and memory

Answer 31

have long been studied using procedures based on both classical and operant conditioning. However, these conditioning procedures also have a long history of usefulness in evaluating drug effects on analgesia, anxiety, addiction potential, and drug discrimination.

Question 32

non-associative learning

Answer 32

sensitization and habituation

Question 33

associative learning

Answer 33

classical conditions (pavlov) and instrumental learning (skinner box)

Question 34

sensitization

Answer 34

an increase in response magnitude to a repeated stimulus

Question 35

habituation

Answer 35

a reduction in response magnitude to a repeated stimulus

Question 36

classical conditioning

Answer 36

theory involves learning a new behavior via the process of association.
- In simple terms, two stimuli are linked together to produce a newly learned response. An innate response to a potent stimulus comes to be elicited in response to a previously neutral stimulus; this is achieved by repeated pairings of the neutral stimulus with the potent stimulus.

Question 37

learning, memory and cognition

Answer 37

instrumental learning and cognitive tests
- mazes
- simple
- complex
- complex problem solving

Question 38

instrumental learning: thorndike’s puzzle box

Answer 38

Through instrumental conditioning, an individual makes an association between a behavior and a consequence.
More than 100 years ago, Thorndike first studied the relationship and a consequence using cats as his research subjects. He timed how long it took the cats to make the appropriate response to escape a “puzzle box”. This might be by pressing a lever inside the box or pulling on some string to open the door. Over time, the cats made the response more quickly, showing that they had learned that a particular behavior was associated with getting out of the box.

Question 39

instrumental learning: operant conditioning chamber (skinner box) and a cumulative recorder

Answer 39

Instrumental learning has been extensively studied using rats (and pigeons) in “Skinner boxes”. The rat typically presses a lever in the cage to receive a reward, often a small pellet of food. Once the animal has learned the connection between pressing the lever and delivery of reward, the contingencies can be altered according to changes in the schedule of reinforcement for receiving reward.

Question 40

instrumental learning: continuous and intermittent reinforcement

Answer 40

This figure shows a few different rates and patterns of lever pressing behavior produced by rewarding animals on different schedules.
Note the high rates of responding on the ratio schedules and comparably lower rates of responding on the interval schedules. This is because animals on interval schedules learn that responding immediately after reward will likely not be rewarded—so they pause their behavior producing the characteristic “fixed interval scallops”. However, if the interval is variable, then fairly constant rates of responding follow (because sometimes they might be rewarded right after receiving reward!).

Question 41

t-maze

Answer 41

(or the variant Y-maze) is a simple maze used in animal cognition experiments to study how rodents function with memory and spatial learning. It is shaped like the letter T (or Y), providing the subject, typically a rodent, with a straightforward choice. The different tasks, such as left-right discrimination and forced alternation, are mainly used with rodents to test reference and working memory. More complex mazes add degrees of difficulty to the task.

Question 42

spontaneous alteration

Answer 42

Reference memory is a kind of long-term memory while working memory is temporary memory used for immediate responses.

Question 43

morris water maze

Answer 43

is widely used to study spatial learning and memory.
There is a submerged escape platform that the rats must first blindly find by swimming throughout the tank and then re-find it again in future trials by remembering the position of the platform in relation to cues from the room. It can also be used to assess damage to particular cortical regions of the brain. It is used to measure the effect of neurocognitive disorders and drugs on spatial learning and possible neural treatments.

Question 44

complex maze: the radial arm maze

Answer 44

also used to measure spatial learning and memory in rats.
It typically has eight equidistantly spaced arms, all radiating from a small circular central platform, with food placed at the ends. The design ensures that, after checking for food at the end of each arm, the rat is always forced to return to the central platform before making another choice. As a result, the rat always has eight possible options.

(Reference memory is assessed when the rats only visit the arms of the maze which contains the reward. The failure to do so will result in reference memory error. Working memory is assessed when the rats enter each arm a single time. Re-entry into the arms would result in a working memory error.)

Question 45

test of cognitive function

Answer 45

the delayed response task
-task is a test of working memory.
The subject responds on the basis of stored internal representations (i.e., memory) rather than information currently present. Typically, the subject receives a brief visual stimulus, like a piece of food, that is then withdrawn and, after a delay of several seconds, attempts to identify the location where the stimulus appeared. They are rewarded if correct.

Question 46

post-mortem examination

Answer 46

A classic procedure is old-fashioned postmortem examination which involves looking at the brain on a gross anatomical level. This figure shows the shrunken brain and enlarged ventricles associated with Alzheimer’s. Alzheimer’s disease is a form of dementia involving progressive loss of psychological functions as a result of widespread loss of cortical and subcortical neurons. Upon autopsy, the brain is clearly shrunken, and the ventricles typically enlarged, showing massive loss of tissue from dying neurons.
- Loss of cells

Question 47

autoradiography

Answer 47

• Several techniques have been developed to determine where in the brain a drug molecule distributes and binds to receptors.
  An autoradiograph is an image on an x-ray film or nuclear emulsion produced by the pattern of decay emissions (e.g., beta particles or gamma rays) from a distribution of a radioactive substance. The film or emulsion is apposed to the labeled tissue section to obtain the autoradiograph (also called an autoradiogram). The auto- prefix indicates that the radioactive substance is within the sample,
• Orange areas on the brain show where the administered cocaine bound to the receptors

Question 48

immunocytochemistry

Answer 48

a common laboratory technique that is used to anatomically visualize the localization of a specific protein or antigen in cells by use of a specific primary antibody that binds to it. The primary antibody allows visualization of the protein under a fluorescence microscope.
This is done by injecting animals with the protein of interest, or a peptide fragment and, after a secondary immune response is stimulated, isolating antibodies from whole serum. The brain tissue is treated with a bath containing the antibodies for staining purposes.
- Immune system discussed last unit – think of how they connect to each other

Question 49

in situ hydridization

Answer 49

is a technique that allows for precise localization of a specific segment of nucleic acid within a histologic section. The underlying basis of ISH is that nucleic acids can be detected through the application of a complementary strand of nucleic acid.

Question 50

encephalogram showing ventricles of the brain

Answer 50

taken after replacing some of the cerebrospinal fluid with air or oxygen so that the brain cavities show clearly.

• The brain is fairly homogenous as well as its structure is concerned besides the ventricles so it can be hard to visualize on an x-ray

Question 51

internal carotid arteriogram

Answer 51

Arteriography or angiography is an imaging technique used to visualize the inside of blood vessels and organs of the body. This is traditionally done by injecting a radio-opaque contrast medium and X-rays to observe the flow of blood through arteries (figure) to note any blockages. The technique was developed by the Portuguese physician and neurologist Egas Moniz.

Question 52

ct

Answer 52

In CT scanning the transmission of x-rays through tissue is read at each point of beam intersection. Multiple narrow beams of x-rays are rotated 180º around one side of the skull while the x-ray detectors are rotated around the opposite side in an identical path. At each degree of rotation, tube and detectors, now moving linearly, make a series of transmission readings (up to several hundred, depending on the model). The transmission characteristics, or radiodensity, of a single region of tissue are calculated by summing the transmission readings of all beams passing through that region. The spatial resolution of CT scans is limited to the distance between these intersection points. The result for each “slice” of brain is a matrix computed from thousands of intersecting radiation intensity measurements, translated into numbers (attenuation coefficients) and visually displayed as areas that are relatively dark or light.

Question 53

in-vivo imaging of the brain PET method

Answer 53

A. The nucleus of an unstable radionuclide emits a positron, which travels a certain distance before it collides with an electron and is annihilated emitting two gamma rays, which then travel in precisely opposite directions. The site of positron annihilation that is imaged may be a few millimeters from the site of origin. For example, the distance between sites of origin and annihilation is 2 mm for 18F and 3 mm for 15O. The distance between the emitting nucleus and site where the positron is annihilated is an absolute limit on the spatial resolution of PET scan images.
B. Gamma rays are detected by an array of crystals and photomultipliers that surround the head. Only signals that are detected simultaneously by diagonally photomultipliers are recorded.
- Areas of the brain that are more active are more likely to have more glucose present in a scan

Question 54

PET scans assess

Answer 54

functional brain activity of people as they undertake different sorts of tasks, such as speaking, reading, and writing. PET entails injecting radioactive substances that decay rapidly into the bloodstream to reach the brain. As the radioactivity decays, it gives off photons, allowing a computer to draw their location on a 2- or 3-dimensional reconstruction of the brain. For example, if a form of radioactive oxygen is administered, more active parts of the brain that use more oxygen can be identified and correlated with the behavior. Damaged brain areas use less oxygen. PET can image many chemicals, thus diseases characterized by chemical changes can be imaged.

Question 55

MRI

Answer 55

use strong magnetic fields, magnetic field gradients, and radio waves acting on spinning atoms to generate images of the organs in the body. MRI calculates the location of spinning atoms by detecting the electrical charge their movement generates. Because brain tissue varies in its concentration of molecules (for example, in nerve fibers versus cell bodies), MRI can use regional differences to reveal excellent brain images.

Question 56

the principle of magnetic resonance imaging

Answer 56

A radiofrequency pulse will excite atomic nuclei, flipping them from the parallel state into the higher energy antiparallel state. Relaxation of the nuclei back into the low energy state generates the MRI signal.

Question 57

functional magnetic resonance imaging

Answer 57

MRI can also determine the relative concentrations of oxygen and carbon dioxide in blood passing through the brain and so can be used to determine regional differences in brain activity. When neural tissue is more active, it consumes more oxygen. Increased oxygen consumption increases local blood flow. This exaggerates the local difference in proportion of blood that has oxygen and blood that doesn’t. This difference can be measured and used by computer to plot where the increased neural activity is happening. Thus, brain function (functional MRI, fMRI) can be imaged and superimposed on brain anatomy (MRI).
- Blood flow increases

Question 58

stereotaxic surgery

Answer 58

There are brain maps of many species of animal, including humans, in which brain areas are located by a three-dimensional Cartesian coordinate system. For the surgery, a landmark on the skull is identified and its coordinates determined using the stereotactic instrument. Then, the difference between the landmark on the skull and the targeted brain area is computed in all 3 directions to determine where to drill a hole in the skull to access the target site.

Question 59

deep brain stimulation

Answer 59

Apply to areas that are under excited in order to balance brain activity

Question 60

manipulating the brain: ablation and lesions

Answer 60

Cortical Aspiration
Electrolytic Lesions
Radiofrequency Lesions
Excitotoxic Lesions
Antisense
- For cortical ablation, a small pipette with a tube attached to provide suction can be used to remove small areas of the brain, usually on the surface of the brain, such as cortex.
- Suction off a portion of the cortex

Question 61

electrolytic lesions are caused by

Answer 61

passing substantial electrolytic current through the tip of an electrode to destroy surrounding tissue.
-These are examples of lesions to the subfornical organ, a circumventricular organ (Fig A, B) and to control tissue (Fig C, D), i.e., not the SFO. This type of lesion will include cell bodies, of course, but also any “fibers of passage” that may traverse the area. The control lesions help determine specificity of effects that may be observed to destruction of the target, i.e., SFO, tissue.
- Blood brain barrier deficient areas

Question 62

excitotoxic lesions are made by

Answer 62

injecting small volumes of excitatory substances into an area that causes the cells to become overactive and die. This destroys cell bodies but leaves fibers of passage intact. Note that the dark cells in figure A (control) are not present in figure B (excitotoxic lesion).
- Apply chemicals that excite neurons

Question 63

effect of antisense on protein synthesis

Answer 63

Antisense RNA can prevent the translation of RNA into product proteins. Antisense RNA, also referred to antisense oligonucleotide, is a single stranded RNA that is complementary to a protein coding messenger RNA with which it hybridizes, and thereby blocks its translation into protein

Question 64

brain stimulation

Answer 64

electrical stimulation of discrete brain areas or chemical stimulation of discrete brain areas. The top right figure depicts an electrode placed deep within rat brain tissue that can be used to emit small amounts of electricity continuously or in small bursts to stimulate surrounding tissue. The figure in lower left depicts one way to infuse solutions with drug. The bottom right shows how the electrodes or cannula are secured to the skull using tiny screws and dentil cement.
If you think a structure is involved, remove it and see what happens as a result
Counter experiment = excite
the portion of the brain that you want to know more about
Depend on stereotaxis surgery in order to get to specific areas of the brain
Administer cytotoxins (will discuss more in a later unit)
Chemicals that would mimic the action of neurotransmitters or other neurotransmitters
Screws put into the skull
In chemical stimulation, insert a hypodermic needle
Dialysis probe – having a membrane that allows certain substances out into circulation and the membranes are chosen for specific size and molecular weight

Question 65

electrophysiological monitoring

Answer 65

method to record electrical activity of the brain. It is typically noninvasive, with the electrodes placed along the scalp, although invasive electrodes implanted deep within tissue are sometimes used. The EEG measures the net sum of the electrical activity of billions of cortical neurons at any moment. These electrical measures are voltage fluctuations resulting from ionic current within the neurons of the brain.
- Electrodes embedded in the hat and line up along the scalp

In order to examine what is happening deep inside the brain, animals are typically used. The cartoon depicts a recording electrode placed deep into the animal’s brain (e.g., perhaps hypothalamus). The lower graph is the actual recording of neural activity from the cells surrounding the tip of an electrode in an animal study.

Question 66

sampling brain chemicals

Answer 66

• The amounts of chemicals in the entire brain, or in discrete brain areas, can be measured. In the technique shown here, small amounts of brain tissue are “punched” out of the brain and assayed for neurotransmitter content (or whatever else is desired to look at).
• microdialysis is used for continuous measurement of the concentration of chemicals, e.g., neurotransmitters, in the extracellular fluid of brain tissue. A small amount of fluid is pushed into the microdialysis tube while simultaneously a small amount of fluid is pulled out. The fluid that is pulled out will have fluid from the extracellular space (containing neurotransmitter) mixed in it.

Question 67

bioassay

Answer 67

involves the response of biological tissue to determine the amount of a substance

Question 68

chemical assay

Answer 68

involves a physical detection method to the amount of substance

Question 69

radioimmunoassay

Answer 69

involves the use of a radiolabeled ligand to determine the amount of a substance

Question 70

measuring chemicals in the brain

Answer 70

After getting the sample from the tissue or from the micro-dialysis
Dependent on the nature of the tissue and how much activity
Bioassay – otto loewi’s determine whether it was a chemical or electro transmission involved in the beating of the heart

Question 71

assays and the standard curve

Answer 71

Bioassay = Involves the response of biological tissue to determine the amount of a substance. In the figure, the rate of plant growth is used to determine the amount of a chemical in the soil.

Chemical Assay = Involves a physical detection method to the amount of a substance. In the example here, the change in color is used to determine the effectiveness of a drug/chemical.

A standard curve is a type of graph used as a quantitative research technique. Multiple samples with known properties are measured and graphed, which then allows the same properties to be determined for unknown samples by interpolation on the graph. The samples with known properties are the standards, and the graph is the standard curve. Making a scale based off of different doses and their response, dependent on the level of the chemical present.