Module 7 How Do We Study the Brain's Structure and Functions?

Question 1

Functional Near-infrared Spectroscopy (fNIRS)

Answer 1

-Noninvasive technique that gathers light transmitted through cortical tissue to image oxygen consumption; form of optical tomography
-Gathers light transmitted through cortical tissue to image oxygen consumption in the brain
-Allows investigators to measure oxygen consumption as a surrogate maker of neuronal activity relatively select cortical regions, even in newborn infants
~When newborns listened to a familiar language, their brain showed a general increase in oxygenated hemoglobin; when they heard un unfamiliar language, oxygenated hemoglobin decrease overall
*But when the babies heard the same sentences played backward, there was no difference in brain response to either language

Question 2

Brain-Behavior analyses combine the efforts

Answer 2

• Anatomists and genetics
• Psychologists and physiologists
• Chemists and physicists
• Endocrinologists and neurologists
• Pharmacologists and psychiatrists
• Computer scientists and programmers
• Engineers
• Biologists

Question 3

Ernset Auburtim

Answer 3

-During a 1861 Anthropological Society of Paris meeting, argued that language functions are located in the brain’s frontal lobes

Question 4

Paul Broca

Answer 4

• A fellow physician who attended the meeting noticed five days later observed a brain-injured patient who had lost his speech, but said “tan” and swear words.
• He examined the man’s brain and found the focus of the injury in the left frontal lobe
• By 1863, he colleceted eight other similar cases and concluded that speech production is located in the third frontal convolution of the left frontal lobe- a region now called ‘Broca’s area’
• His finding attracted others to study brain-behavior relationships in patients

Question 5

Neuropsychology

Answer 5

• Study of the relationships between brain function and behavior, especially in humans
• Measuring brain and behavior increasingly includes noninvasive imaging, complex neuroanatomical measurement, and sophisticated behavioral analysis

Question 6

Primary Tools of Neuroanatomy were Histological

Answer 6

• Brains were sectioned postmortem, and the tissue (histo- in Greek) was stained with various dyes
• There has been progression in microscopy toward greater resolution and specificity and a movement from visualizing dead tissue to living tissue
• Scientists can stain sections of brain tissue to identify cell bodies in the brain viewed with a light microscope, and they can selectively stain individual neurons to reveal their complete structure; an electron microscope makes it possible to view synapses in detail; multiphoton imaging can generate a three-dimensional image of living tissue

Question 7

Korbinian Brodmann

Answer 7

-Divided the cerebral cortex into many distinct zones based on the characteristics of neurons in those zones

Question 8

Early Twenty-first Century

Answer 8

-Dozen of techniques had developed for labeling neurons and their connections, as well as glial cells

Question 9

Super-resolution Microscopy

Answer 9

-Is also being used to identify the locations of different receptors on the membranes of cells

Question 10

Contemporary Techniques

Answer 10

• Allow researchers to identify molecular, neurochemical, and morphological (structural) differences among neuronal types and ultimately to relate these characteristics to behavior
• These techniques for visualizing neurons play a role in studying the connections between anatomy and behavior

Question 11

Learning can be corelated with variety of neuroanatomical change

Answer 11

-Such as modification in the synaptic organization of cells in specific cortical regions or in the number of newly generated cells that survive in the dentate gyrus, a subregion of the hippocampus

Question 12

Experimental Evidence

Answer 12

-Reveals that preventing the growth of new dentate gyrus neurons lead to certain kinds of memory deficits
~To test this idea that neurons of the dentate gyrus contribute to object memory formation within a context, researchers tested healthy rats and ADX rats-rats with adrenal glands removed, thus eliminating the hormone corticosterone
*Without corticosterone, neurons in the dentate gyrus die

Question 13

Experimental context with rats

Answer 13

-Each context contained a different type of object
-Rats were placed in either context A or context B but with two different objects-one from that context and the second from the other context
-On the test day, the rate were placed in either context A or context b but with two different objects-one from that context and a second from the other context
~When healthy rats encounter objects in the correct context, they spend little time investigating because the objects are familiar; however, if they encountered an object in the wrong context, they are curious and spend about three-quarters of their time investigating, essentially treating the mismatched object as new
-The ADX rats with fewer cells in the dentate gyrus treated the mismatched and in-context object the same, spending about half of their investigation time with each object
-Another of ADX rate given treatment known to increase neuron generation in the dentate gyrus-enriched housing and exercise in running wheels- was unimpaired at the object-context mismatch task
~Concludes that cellular changes in the dentate gyrus and behavioral changes are closely linked: neurons of the dentate gyrus are necessary of contextual learning

Question 14

Brainbow

Answer 14

• Not the discovery of stains that can highlight brain cell features, their complexity and connections would remain unknown
• Jean Livet and his colleagues at Harvard developed a transgenic technique that involves labeling different neurons by highlighting them with distinct colors; to mimic the wat an LCD or LED monitor produces the full range of colors that the human eye can see by mixing only red, green, and blue
• Scientists introduced genes that produced cyan (Blue), green, and red fluorescent proteins into mice cells
• Red genes is obtained from coral, and the blue and green genes are obtained from jellies
• The mice also received a bacterial gene called Cre, which activates the color genes inside the cells; due to change factors; however, the extent to which each gene is activator variable expression of the color-coding genes result in cells that fluoresce in at least 100 hues
• When viewed through a fluorescent microscope sensitive to these wavelengths, individual brain cells and their connections can be visualized because they have slightly different hues
• Individual cells can be visualized, Brainbow offers a way yo describe where each neuron sends its processes and how it interconnects with other neurons
• By visualizing living brain tissue in a dish, Brainbow provides a method for examining changes in neural circuits with the passage of time
• Will provide useful for examining populations of cells and this connects-such as which cells are implicated in specific brain diseases
• Could be turned on at specific times, as an individual ages or solves problems
• Even the simplest brain contains extraordinary numbers of neurons and fibers
• Modifications that restrict visualization to only a few cells and fibers at a time are necessary for their connections to be understood

Question 15

behavioral Neuroscience

Answer 15

• Study of the biological bases of behavior in humans and other animals
• Seek to understand the brain-behavior relationship in humans and other animals

Question 16

Major challenge for behavioral neuroscientists

Answer 16

• Is developing methods for studying both typical and atypical behavior
• Measuring behavior in humans and laboratory animals differs in large part because humans speak: investigators can ask them about their symptoms or give them paper-and-pencil and computer-based tests to identify specific symptoms
• Measuring behavior in laboratory animals are more complex; researches must learn the animals language, in short researchers must develop ways to enable the animals to reveal their symptoms

Question 17

Ethology

Answer 17

• The development of the fields of animal learning
• The objective study of animal behavior, especially under natural conditions, provided the basis from modern behavioral neuroscience

Question 18

Neuropsychological Testing of Humans

Answer 18

-The brain has exquisite control of functions ranging from movement control and sensory perception to memory, emotion, and language
-Any analysis of behavior must be tailored to the particular function(s) under investigation
~Consider the analysis of memory
-People with damage tot he temporal lobes often complain of memory disturbance
~Memory is not a single function; rather, multiple independent memory systems exist
*We have memory for events, colors, names, places, and motor skills, among other categories, and each must be measured separately
**It would be rare for someone to be impaired in all forms of memory

Question 19

Neuropsychological Tests

Answer 19

-Three distinct forms of memory
~The Corsi block-tapping requires participants to observe an experimenter tap a sequence of blocks- blocks 4,6,1,8,3 for instance; the task is to repeat the sequence correctly
*Participant does not see number on the blocks but rather must remember the location of the tapped blocks

Question 20

Block Span

Answer 20

-Provides a measure of short-term recall of spatial position
-the test can be made more difficult by determining the maximum block span of an individual participant and then adding one
-The participant will fail on the first presentation but, given the span + 1 repeatedly, will eventually learn it
-Span +1 identifies a different form of memory from block span
~Different types of neurological dysfunction interfere differentially with tasks that superficially appear quite similar
-Block span measures the short-term recall of information, where as the span +1 task reflects the learning and long-term memory storage of information

Question 21

Mirror-drawing Task

Answer 21

-Requires a person to trace a pathway, such as a start, by looking in a mirror
-Motor task proves difficult because out movements appear backward in a mirror
-With practice, participants learn how to accomplish the task accurately, and they show considerable recall of the skill when retested days later
~Patients with certain types of memory problems have no recollection of learning the task on the previous day but neverless preform it flawlessly

Question 22

Recent Memory Task

Answer 22

-Participants are shown a long series of cards, each bearing two stimulus items that are words or pictures
-On some trials, a question mark appears between items
~Their task is to indicate whether that have seen the items before and, if so, which item they saw most recently
*They might be able to recall that they have seen items before but may be unable to recall which was most recent
*Conversely, they might not be able to identify the items as being familiar, but when forced to choose the most recent one, they may be able to identify it correctly

Question 23

Behavioral Repertories

Answer 23

-The rats display a long list of capabilities, some of which are categorized, that can be independently examined to understand the functional underpinning of those behaviors

Question 24

Place Learning

Answer 24

• The rat must find the platform from a number of different starting locations in the pool.
• Only cues available are outside the pool, so the rat’s must learn the relationship between several cues in the room and the platform’s location

Question 25

Matching-to-place Learning

Answer 25

-The rat has already learned that a platform always lies somewhere in the pool, but the rat enters the pool from different starting location every day -The rat is released and searches for the platform ~Once the rat finds the platform, the rat is removed from the pool and, after a brief delay (10 seconds), is released again -The rat is to develop a strategy for finding the platform consistently: it is always in the same location on each trial each day, but each new day brings a new location for the rat.

Question 26

Landmark

Answer 26

- The platform's location is identified by a cue on the pool wall - The platform moves on every trial, but the relationship to the cue is consistent - The brain is learning that the distant cues outside the pool are irrelevant; only the local cues is relevant

Question 27

Major problem facing people with stroke

Answer 27

- A deficit in controlling hand and limb movements - Has prompted considerable interest in devising ways to analyze such motor behaviors for the purpose of testing new therapies for facilitating recovery

Question 28

Manipulating Brain-behavior Interactions

Answer 28

- The precise manner depending on the specific research question being asked - Research can manipulate the whole animal by exposing it to different diets, social interactions, exercise, sensory stimulation, and a host of other experiences - The principal direct techniques are to inactivate the brain via lesions or with drugs or to activate it with electrical stimulation, drugs, or light

Question 29

Brain Lesions

Answer 29

-Used for brain manipulation is to ablate (remove or destroy) tissue

Question 30

Ablation

Answer 30

- Karl Lashley fried to find the site of memory in the brain - Trained monkeys and rats on various mazes and motor tasks and then removed bits of cerebral cortex, with the goal of producing amnesia for specific memories - Memory loss was related to the amount of tissue he removed - Conclusion is that memory is distributed throughout the brain and not located in any single place - Research strongly indicates that specific brain functions and associated memories are indicated localized to specific brain regions

Question 31

Stereotaxic Apparatus

Answer 31

- Surgical instrument that permits a researcher or neurosurgeon to target a specific part of the brain - The head is held in a fixated position, and because the location of brain structures is fixed in relationship to the junction of the skull bones, it is possible to visualize a three-dimensional brain map - Rostral-caudal (front-to-back) measurements correspond to the y-axis - Dorsal-ventral (top-to-bottom) measurements correspond to the z-axis, are made relative to the surface of the brain - Medial-lateral measurements, x-axis, are made relative to the midline junction of the cranial boned

Question 32

Parkinsonian Tremor

Answer 32

-Which the hands can shake so severely that the afflicted person cannot hold a glass of water ~The most widely use surgical treatment today is drill a hole in the skull and, using stereotaxic coordinates obtained for that patient with MRI, target the globus pallidus -An electrode is then lowered into the globus pallidus, and currents is passed through it to destroy the structure and relieve the patient of the tremor

Question 33

High-intensity Focused Ultrasound (HIFU)

Answer 33

-Now achieve the same result without the invasive surgery -Uses many individual untrasonic beams that are all pointed at the same spot in the brain ~Each beam passes through tissue with little effect; at the convergent point where all the beams intersect, the energy heats the tissue *Lightly heating the tissue temporarily prevents that part of the brain from working properly, thereby informing the surgeons that their targeting is correct ~The tissue heating can then continue until the target is permanently destroyed and the tremor is noninvasively eliminated

Question 34

Compensation

Answer 34

- Following brain damage, the neuroplasticity ability to modify behavior from that used prior to the damage - To avoid compensation following premiant lesions, researchers have also developed temporary and reversible lesion techniques such as regional cooling

Question 35

Regional cooling

Answer 35

- Prevents synaptic transmission - A hollow metal coil is placed next to a neural structure; then chilled fluid is passed through the coil, cooling the brain structure to about 18C - When the chilled fluid is removed from the coil, the brain structure quickly warms, and synaptic transmission is restored

Question 36

GABA local administration

Answer 36

- Which increases local inhibition and in turn, prevents the brain structure from communicating with other structures - Degradation of GABA agonist reverses the local inhabitation and restores function

Question 37

Brain Stimulation

Answer 37

-The brain operates on both electrical and chemical energy, so its possible to selectively turn the brain regions on and off by using electrical or chemical stimulation -Mid-twentieth century, the first to use electrical stimulation directly on the human cerebral cortex during neurosurgery -Later researchers used stereotaxic instruments to place an electrode or a cannula in specific brain locations -The objective: enhancing or blocking neuronal activity and observing the behavioral effects -Can also be used as a therapy ~The intact cortex adjacent to cortex injured by a stroke is stimulated electrically, for example, it leads to improvement in motor behaviors

Question 38

Electrical self-stimulation

Answer 38

- The animal have the opportunity to press a bar that briefly turns on the current, they quickly learn to press the bar to obtain the current - It appears that the stimulation is affecting a neural circuit that involves both eating and pleasurers

Question 39

Deep-brain Stimulation (DBS)

Answer 39

-A neurological technique, electrodes implanted in the brain stimulate a targeted area with continuous pulse of low-voltage electrical current to facilitate behavior -Subcortical structures, for example, DBS to the globue pallidus in the basal ganglia of Parkinson patients make movements smoother, often allowing patients to dramatically reduce their intake of medications -Using several neural targets is an approved treatment for obsessives-compulsive disorder ~Experimental trials are under way to identify the brain regions optimal for DBS to be used as a treatment for intractable psychiatric disorders such as major depression, schizophrenia, and possibly for epilepsy ~May also be used as a treatment for stimulating recovery from traumatic brain injury (TBI)

Question 40

Transcranial Magnetic Stimulation (TMS)

Answer 40

-Procedure in which a magnetic coil is placed over the skull to stimulate the underlying brain; used either to induce behavior or to disrupt ongoing behavior -A high-voltage current pulsed through the coil produces a rapid increase and subsequent decrease in the magnetic field around the coil; the magnetic field easily passes through the skull and causes a population of neurons in the cerebral cortex to depolarize and fire -If the motor cortex is stimulated, movement is evoked; or if a movement is in progress, it is distrupted -Similarly, if the visual cortex is stimulated, the participant see dots of light (phosphenes) ~The effect of brief pulses of TMS do not outline the stimulation, but repetitive TMS (rTMS), or continuous stimulation for up to several minutes, produces more long-lasting effects, including changing function or temporarily inactivating tissue -TMS and rTMS can be used to study brain-behavior relationships in healthy participants, and rTMS has been tested as a potential treatment for a variety of behavioral disorders.

Question 41

Drug Manipulation

Answer 41

-Brain activity can also be stimulated by administration of drugs that pass either into the bloodstream and eventually enter the brain or through an indwelling cannula that allows direct application of the drugs to specific brain structures -Drugs can influence the activity of specific neurons in specific brain regions ~Example *Haloperidol, used to treat schizophrenia, reduces DA neuron function that makes healthy rats dopey and inactive (hypokinetics) -In contrast, drugs that increase dopaminergic activity, such ass amthamines, produce hyperkinetic rats (hyperactive rats) ~The advantage of administering drugs is that their effects wear off in time as the drugs are metabolized *Making it possible to study drugs effects on learned behaviors, such as skilled reaching and then to re-examine the behavior after the drug effect wears of

Question 42

Claudia Gonzalez

Answer 42

-Administered nicotine to rats as they learned a skilled reaching task, then studied their later acquisition of a new skilled reaching task ~The researchers found that the earlier nicotine-enhanced motor learning impaired the later motor learning -The findings surprised the investigators, but now appears that repeated exposure to psychomotors stimulants such as amphetamine, cocaine, and nicotine can produce long-term effects on the brain's later plasticity (its ability to change in response to experience), including learning specific tasks

Question 43

Synthetic Biology

Answer 43

-Design and construction of biological devices, systems, and machines not found in nature -Has transformed how neuroscientist manipulate brain cells -Techniques include inserting or deleting a genetic sequence into the genome of a living organism ~New technique called CRISPR-Cas9

Question 44

CRISPR-Cas9

Answer 44

-Clustered Regularly interspaced Short Palindromic Repeats, one of many CRISPR techniques, was discovered in bacteria for fighting viruses; it serves as an all-purpose tool for cutting the DNA of any cell -Simply provide the bacteria's Cas9 protein with the RNA sequence corresponding to the length of DNA they would like to remove from the subject -The CRISPR system can be used to silence one or many genes by cutting out those regions in the DNA ~Then the DNA's repair machinery can be harnessed to insert a new sequence that replaces the one that was removed -As a therapeutic intervention, it could eventually lead to the elimination of many forms of inherited disease ~Could also counter antibiotic-resistant microbes, disable parasites, and improve food security

Question 45

Optogenetics

Answer 45

-Transgenic technique that combines genetics and light to control targeted cells in living tissue -A sequence that codes for a light-sensitive protein associated with an ion channel enables investigators to use light to change the shape (conformation) of the channel -Based on the discovery that light can activate certain proteins that occur naturally and have been inserted into cells of model organisms ~Example *Opsins *Halorhodopsin -Investigators can insert light-sensitive proteins into specific neuron types, such as pyramidal cells of the CA1 region of the hippocampus, and use light to selectively activate just that cell type -Researchers hail optogenetic for its high spatial and temporal (time) resolution; ion channels can be placed into specific cell lines and turned on and off on millisecond time scales -Find application in behavioral studies ~Example *The amygdala is a key structure in generating fear in animals; if the target with opsins and then exposed to an inhibitory light, rats immediately show no fear and wander about in a novel open space; as soon as the light is turned off, they scamper back to safe hiding place

Question 46

Opsins

Answer 46

-Proteins derived from microorganisms, combine a light sensitive domain whit ion channel -Used for the optogenetic technique was channelrhodopsin-s (ChR2) ~When ChR2 is expressed in neurons and exposed to blue light, the ion channel opens and immediately depolarizes the neuron, causing excitation

Question 47

Halorhodopsin (NpHR)

Answer 47

-Stimulation with a green-yellow light activates a chloride pump, hyperpolarizing the neuron and causing inhabitation

Question 48

Chemogenetics

Answer 48

-Transgenic technique that combines genetic and synthetic drugs to activate targeted cells in living tissue -The inserted synthetic genetic sequence codes for a G protein-coupled receptor engineered to respond exclusively to a synthetic small-molecule "designer drug" -Better known by the acronym DREADD (Designer receptor exclusively activated by designer drugs) ~Principal advantage is that the drug activates only the genetically modified receptors, and the receptors are activated only by designer drugs, not by endogenous molecules *Specificity is high, but temporal resolution is much lower that with optogenetic because receptors are activated by drugs rather than by light

Question 49

Four Major Techniques for tracking the Brain's Electrical Activity

Answer 49

-Single-cell recorder -Electroencephalography (EEG) -Event-related Potentials (ERPs) -Magnetoencephalography (MEG) ~Used to record electrical activity from different parts of neurons; the electrical behavior of cell bodies and dendrites, which give rise to graded potential, tends to be much more varied and slower than the behavior of axons, which conduct action potential

Question 50

Recording Action Potentials

Answer 50

-Early 1950s, became possible to record the activity of individual cells by measuring a single neuron's action potentials with fine electrodes inserted into the brain -These microelectrodes can be placed next to a cell (extracellular recording) or inside cells (intracellular recording) ~Extracellular recording techniques make it possible to distinguish the activity of as many as 40 neurons at once ~~Intracellular recording allows direct study and recording of a single neuron's electrical activity -The two disadvantages of inserting an electrode into a cell are that ~It can kill the cell ~It cannot be done in awake, free moving animals -Single-cell recording is therefore confined to neurons grown in a dish or, for short periods (hours), to neurons in living brain slices -From extracellular recordings that cells in the brain's various sensory regions are highly sensitive to specific stimuli; some cells in the visual system fire vigorously to specific wavelengths of light (color) or to specific orientations of bars of light (vertical) -Other cell in this region respond to more complex patterns, such as faces or hands -Cells in the auditory system respond to specific sound frequencies (low or high pitch) or to more complex sound combinations, such a speech

Question 51

Place Cells

Answer 51

- Neurons maximally responsive to specific locations in the world - Code the spatial location of the animal and contribute to a spatial map of the world in the brain

Question 52

John O'Keefe

Answer 52

-Discoveries of cells that constitute a positioning system in the brain -Also demonstrated that, in mice with a genetically engineered mutation that produces deflicts in spatial memory, place cells lack specificity: the cell fire to a very broad region of their world; as a result, these mice have difficulty finding their way around, much as human patients with dementia tend to get lost. ~One reason may be that a change similar to engineered mutation in mice takes place in human brain cells

Question 53

EEG

Answer 53

-Measures the summed graded potentials from many thousands of neurons

Question 54

Electrocortcography (ECoG)

Answer 54

- Graded potentials recorded with electrodes places directly in the surface of the brain - A method used during neurosurgery , electrodes are placed directly on the cerebral cortex

Question 55

EEG Recordings

Answer 55

- EEG changes as behavior changes - An EEG recorded from the cortex displays an array of patterns, some rhythmical - The living brain's electrical activity is never silent, even when a person is asleep or comatose

Question 56

EEG Patterns

Answer 56

-When a person is arroused, excited, or even just alert has a low amplitude and a fast frequency -This pattern is typical od an EEG taken from anywhere on the skull of an alert subject-not only humans but other animals too -When a patient is calm and quietly relaxed, especially with eyes closed, the rhythmical brain waves often emerge -Changes as a person moves from drowsiness to sleep and finally into deep state ~Rhythms become progressively slower and larger in amplitude; still slower waves appear during anesthesia, after brain trauma, or when a person is in a coma -Only in brain death does the EEG permanently become a flat line -A reliable tool for monitoring sleep stages, estimating the depth of anesthesia, evaluating the severity of head injury, and searching for brain abnormalities -In epilepsy, brief periods of impaired awareness or unresponsiveness and involuntary movement associated with spiking patterns in the EEG characterize electrographic seizures -Is an essential tool in diagnosis of epilepsy and in determining the kind of epilepsy and seizures the person had

Question 57

Alpha Rhythms

Answer 57

- Regular wave pattern in an electroencephalogram; found in most people when they are relaxed with eyes closed - Are extremely regular, with a frequency of approximately 11 cycles per second and amplitudes that wax and wane as the pattern is recorded - In humans are generated in the region of the visual cortex at the back of the brain; if a relaxed person is disturbed, performs mental arithmetic, or opens their eyes, the alpha rhythms abruptly stops

Question 58

Event-related potential (ERPs)

Answer 58

-Complex electroencephalographic waveform related in time to a specific sensory event -Are largely the graded potentials of dendrites that a sensory stimulus triggers -Are mixed in with so many other electrical signals in the brain that they are difficult to spot just by visully inspecting an EEG recording -One way to detect is to produce the stimulus repeatedly and average the recording responsive ~Averaging tends to cancel out any irregular and unrelated electrical activity, leaving in the EEG record only the potentials the stimulus generated -Caused by a sensory stimulus in hard to discern from all the other electrical activity around it -Pattern consist of a number of negative (N) and positive (P) waves that occur within a few hundred milliseconds after the stimulus -To spoke words even contain distinctive peaks and patterns that differences peaks and patterns that differentiate such similar-sounding words as cat and rat -EEG technique is noninvasive, electrodes are placed on the scalp, not in the brain -EEG and ERPs are inexpensive and can be recorded from many brain areas simultaneously by pasting an array of electrodes (sometimes more than 200) onto different parts of the scalp ~Can help with map brain functions -Can not only detect which brain areas are processing particular stimuli but can also be used to study the order in which different regions participate -These seconds are important because we want to know the route that information takes as it travels through the brain -Can also be used to study how children learn and process information differently as they mature, as well as how a person with a brain injury compensates for the impairment by using undamaged brain regions -Can even help reveal which brain areas are most sensitive to aging and are therefore more closely related to declining behavioral functions among the elderly

Question 59

Mild Head Injury and Depression

Answer 59

- Spinal symptoms gradually cleared, but irritability, anxiety, and depression persisted even 2 years later - He did display significant attentional and short-term memory defects - All patients with head injuries displayed a delayed P3 wave, but only those who were depressed as well also had a delayed N2 wave - ERP can identify cerebral processing abnormalities in people with depression after mild head injury, even when MRI scans are negative

Question 60

Magnetoencephalogram (MEG)

Answer 60

- Magneto cephalogram potentials recorded from detectors placed outside the skull - Measurements not only describe the electrical activity of neuronal groups but also localize the cell groups generating the measured field in three dimensions - Magnetic waves conducted through living tissue undergo less distortion than electrical signals do - Can yield a higher resolution than an ERP - More precisely identify the source of the activity being recorded - Had proved useful in locating the source of epileptic discharge; the disadvantage of MEG is its high cost in comparison with the apparatus used to produce EEGs and ERPs

Question 61

Computed Tomography (CT)

Answer 61

-X-ray technique that produces a static three-dimensional image of the brain in cross section -Cormack abd Hounsfield both recognized that a narrow X-ray beam could be passed through the same object as many angles, creating many images; the images could then be combined with the use of computing and mathematical techniques to produce a three-dimensional image of the brain -Resembles the way in which our two eyes (and our brain) work in concert to perceive depth and distance to locate an object in space -Coordinates many more than two images-roughly analogous varies with tissue density ~High-density tissue, such as bone, absorbs a lot of radiation ~Low-density material, such as ventricular fluid or blood absorbs little *Neural tissue absorption lies between these extremes -The scanning software translates these differences in absorption into the brain image in which dark colors indicate low-density regions and light color indicate high-density regions

Question 62

Broca Aphasia

Answer 62

-The inability to speak fluently despite having average comprehension and intact vocal mechanisms

Question 63

Magnetic Resonance Imaging (MRI)

Answer 63

-Technique that produces a static three-dimensional brain image by passing a strong magnetic field through the brain, followed by a radio wave, then measuring a radiofrequency signal emitted from hydrogen atoms -Is based on the principle that hydrogen atoms behave like spinning bar magnets in the presence of a magnetic field -Normally hydrogen atoms point randomly in different directions, but when placed in a large, static magnetic field, they line up in parallel as they orient themselves with respect to the static field's line of force -Radio pulses are applied to a brain whose atoms have been aligned in this manner, and each radio pulse forms a second magnetic field ~The second field causes the spinning atoms to deviate from the parallel orientation caused by the static magnetic field to a new orientation -As each radio pulse ends and the hydrogen atoms realign with the static field, they emit a tiny amount of energy, and the coil detects this realignment ~Based on the signals from the coil, a computer re-creates the position of the hydrogen nuclei, producing a magnetic resonance image

Question 64

Diffusion tensor Imaging (DTI)

Answer 64

-Magnetic resonance imaging method that can image fiber pathways in the brain by detecting the directional movements of water molecules -Is an MRI method that detects the directional movements of water molecules to image nerve fiber pathways in the brain ~Water can move relatively freely along the axon but less freely across cell membranes -The direction of this water movement is detected by a coil and interpreted by a computer -Can delineate abnormalities in neural pathways; they are also used to identify changes in fiber myelination, such as the damage that leads to myelin loss in multiple sclerosis -Easily detects abnormalities such as those that occur in multiple sclerosis, stroke, or concussion, in the imaged fiber pathways and in their myelin sheaths

Question 65

Magnetic Resonance Spectroscopy (MRS)

Answer 65

- Magnetic resonance imaging method that uses the hydrogen proton signal to determine the concentration of brain metabolites - Is an MRI method that uses the hydrogen proton signal to determine the concentration of brain metabolites such as N-acetylaspartate (NAA) in brain tissue - This measurement is especially useful for detecting persisting abnormalities in brain metabolism in disorders such as concussions

Question 66

Functional Magnetic Resonance Imaging (fMRI)

Answer 66

-Magnetic resonance imaging technique that measures brain activity indirectly by detecting changes associated with blood flow; often used to measure cerebral blood flow during cognitive testing or resting -Oxygen is carried on the hemoglobin molecule in red blood cells; changes in the ratio of oxygen-rich hemoglobin to oxygen-poor hemoglobin alters the blood's magnetic properties because oxygen-rich hemoglobin is less magnetic than oxygen-poor hemoglobin ~Ogawa showed that MRI could accurately match these changes in magnetic properties to specific locations -Signals which areas are displayed changes in activity -The dense blood vessel supply to the cerebral cortex allows for a spatial resolution of fMRI on the order of 1 millimeters, affording good spatial resolution of the brain's activity source ~Because fMRI is not as precise as that obtained with EEG recordings and ERPs ~Is that subjects must lie motionless in a long, noisy tube, an experience that can prove claustrophobic *The confined space and lack of mobility also restrict the types of behavioral experiment that can be preformed -Is a major tool on cognitive neuroscience

Question 67

Resting-state fMRI (rs-fMRI)

Answer 67

-Magnetic resonance imaging method that measures changes in oxygen when the individual is resting (not engaged in a specific task) -Is collected when participants have their eyes closed or asked to look at a fixation cross and to keep their eyes open -The scanner collects brain activity, typically for at least 4-minute blocks ~Researchers are attempting to shorten this period by increasing the strength of the static magnetic field and developing more sensitive coils -Statistical analysis of the data entails correlating activity in different brain regions over time -Although rs-fMRI is still in its growth phase, investigators already have identified many consistent networks of brain activity and abnormalities in disease states such as dementia and schizophrenia where patients have trouble with preforming cognitive tasks

Question 68

Optical Tomography

Answer 68

- A functional imaging technique that operates on the principle that an object can be reconstructed by gathering light transmission through it - One requirement is that the object at least partially transmit light - Can image soft tissue, such as that in the breast or the brain

Question 69

Positron Emission Tomography (PET)

Answer 69

-Imaging technique that detects changes in blood flow by measuring changes in the uptake of compounds such as oxygen or glucose; used to analyze the metabolic activity of neurons -Detects changes in the brain's blood flow by measuring changes in the uptake of compounds such as oxygen and glucose -Is a doughnut-shaped array of radiation detectors that encircles a person's head ~A small amount of water labeled with radioactive molecules is injected into the bloodstream -The person injected with these molecules is in no danger because the molecules used, including the radioactive isotope oxygen-15 (15O) are very unstable ~They break down in just a few minutes and are quickly eliminated from the body

Question 70

Radioactive 15O

Answer 70

-Molecules release tiny positivity charged subatomic particles known as positrons

Question 71

Positrons

Answer 71

- Are emitted from an unstable atom because the atom is deficient in neutrons - Are attracted to the negatively charged electrons in the brain, and the collision of the two particles leads to annihilation of both, which produces energy

Question 72

Two protons

Answer 72

- A unit of light energy, leaves the head at the speed of light and is detected by PET camera - The photons leave the head in exactly opposite directions from the site of positron-electron annihilation, so annihilation photons detectors can detect their source - A computer identifies the coincident photons and locates the annihilation source to generate the PET image

Question 73

PET System

Answer 73

-Enables blood-flow measurement in the brain because the unstable radioactive molecules accumulate there in direct proportion to the rate of local blood flow ~Local blood flow in turn is related to neural activity because potassium ions released from stimulated neurons dilate adjacent blood vessels; the more the blood flow, the higher the radiation count recorded by the PET camera -Does not measure local neural activity directly; rather, it infers activity on the assumption that blood flow increases where neuron activity increases

Question 74

Subtraction Procedure

Answer 74

- Subtract the blood-flow pattern when the brain is in a carefully selected control state from the pattern of blood flow imaged when the subject is engaged in the task under study - Subtraction process images the change in blood flow between the two states; the change can be averaged across subjects to yield a representatives average image difference that reveals which brain areas are selectively active during the task

Question 75

PET Radiochemical

Answer 75

-So-called radiopharmaceuticals used in diagnosing human patients, must be prepared in a cyclotron quite close to the scanner because their half-lives are so short that transportation time is a severely limiting factor ~Generating these materials is very expensive -Has important advantages over other imaging methods ~Can detect the decay of literally hundreds of radiochemical, which allows the mapping of a wide range of brain changes and conditions, including in pH, glucose, oxygen, amino acids, neurotransmitters, and proteins ~Can detect relative amounts of a given neurotransmitter, the density of neurotransmitter receptors, and metabolic activities associated with learning, brain poisoning, and degenerative processes that might be related to aging ~Is widely used to study cognitive function with great success *Example **PET confirms that various brain regions preform different functions

Question 76

Hybrid Scanners

Answer 76

-PET with CT -PET with MRI -PET with MRI and EEG ~The advantage of these hybrid scanners is that they can acquire high-quality anatomical images and then overlay the functional/metabolic image information, allowing for precise localization that was not available before-all within a single examination

Question 77

Neuron

Answer 77

-Are regulated by genes, DNA segments that encode the synthesis of particular proteins with cells

Question 78

Gene control

Answer 78

- The production of chemicals in a cell, so it is possible to relate behavior to genes and to chemicals inside and outside the cells - Chemical and genetic approaches require sophisticated technologies that have seen major advances in the past two decades

Question 79

Microdialysis

Answer 79

-Technique used to determine the chemical constituents of extracellular fluid in freely moving animals -Had found clinical application over the past 15 years ~A catheter with a semipermeable membrane at its tip is placed in the brain *A fluid flows through the cannula and passes along cell membrane; simple diffusion drives extracellular molecules across the membrane along their concentration gradient -Is used in some medical centers to monitor chemistry in the injured brain ~The effects of TBI or stroke can be worsened by secondary events such as a drastic increase in the neurotransmitter glutamate -Biochemical changes can lead to irreversible cell damage and death; physicians monitor such changes, which can then be treated

Question 80

Striatum

Answer 80

- Caudate nucleus and putamen of the basal ganglia | - Microdialysis will record an increase of DA within the basal ganglia regions of the caudate nucleus and putamen

Question 81

Cerebral Voltammetry

Answer 81

-Technique used to identify the concentration of specific chemicals in the brain as animals behave freely -A small carbon fiber electrode and a metal electrode are implanted in the brain, and a weak current is passed through the metal electrode. ~The current causes electrons to be added to or removed from the surrounding chemicals *Changes in extracellular levels of specific neurotransmitters can be measured as they occur -Different currents lead to changes in different compounds, it is possible to identify levels of different transmitters, such as 5-HT or DA, and related chemicals

Question 82

Voltammetry

Answer 82

- Has the advantage of not requiring the chemical analysis of fluid removed from the brain, as microdialysis dose, but it has the disadvantage of being destructive - The chemical measurements require the degradation of one chemical into another, making the technology suitable only for scientific studies in animals

Question 83

Brain-deriver Neurotrophic Factor (BDNF)

Answer 83

-Plays an important role in stimulating neural plasticity, and low levels of BDNF have been found with mood disorders such as depression

Question 84

Gene Expression

Answer 84

- The way genes become active or not - While epigenetic factors do not change the DNA sequence, the genes that are expressed can change dramatically in response to environment and experience - Can result from widely ranging experiences, including chronic stress, traumatic events, drugs, culture, and diseases

Question 85

Epigenetic Differences

Answer 85

-In the hippocampal tissue obtained from two groups of humans ~Suicides with histories of childhood abuse ~Either suicides with no childhood abuse or control who died of other causes -Changes found in the abused suicides victims parallels those found in the rats with inattentive mothers, again suggesting that early experiences can alter hippocampal organization and function via changes in gene expression

Question 86

Attention-Deficit/Hyperactivity Disorder (ADHD)

Answer 86

-Are probably the most common disorder of brain and behavior in children, with an increase of 4 percent to 10 percent of school aged children -often goes unrecognized, an estimated 50% of children with ADHD still show symptoms in adulthood, where its behaviors are associated with family breakups, substance abuse, and driving accidents -Generally believed to be a dysfunction in the noradrenergic or dopaminergic activating system, especially in the frontal basal ganglia circuitry -Psychomotor stimulants such as Ritalin and Adderall act to increase brain levels of noradrenaline and dopamine and are widely used for treating ADHD -Most likely affected areas are the frontal lobe and subcortical basal ganglia ~Evidence of reduced brain volumes in these regions in ADHD patients is growing, as is evidence of an increase in the dopamine transporter protein ~The DA transporter increase would mean that DA reuptake into the presynaptic neuron occurs faster than is does in the brains of people without ADHD; the result is a relative decrease in DA *Ritalin works by blocking DA reuptake

Question 87

Morphology (Structure)

Answer 87

-This approach allows details analysis of both macro and micro structure, depending on the method chosen

Question 88

Neurons Generate Electrical Activity in Relationship

Answer 88

- To behavior or on functional changes in brain activity during specific types of cognitive processing

Question 89

Both approaches are legitimate

Answer 89

-The goal is gaining an understanding of brain-behavior relationships

Question 90

Temporal Resolution

Answer 90

-How quickly the measurement or image is obtained

Question 91

Spatial Resolution

Answer 91

-The accuracy of localization in the brain

Question 92

Studies of brain-injured patients

Answer 92

-Must take into account factors such as the subject's ability to maintain attention for long periods- during neuropsychological testing, or imaging studies

Question 93

ADHD has proved difficult to treat in children

Answer 93

- Interest in developing an animal model is high - One way to proceed is to take advantage of the normal variance in the performance of rats on a variety of tests of working memory and cognitive functioning-tests that require attentional processes - Many studies show that treating rats with the dopaminergic agonist methylphenidate (Ritalin), a common treatment for children diagnosed with ADHD, actually improves the performance of rats that do poorly on tests requiring attentional processes

Question 94

Dopaminergic Abnormalities

Answer 94

-Are believed to be one underlying symptom of ADHD in children ~Methylphenidate can reverse behavioral abnormalities, both in children and ADHD and in the SHR rats

Question 95

Four Principles used as guidlines in Canada for reviewing experimental and teaching protocols that will use animals

Answer 95

- The use of animals in research, teaching, and testing is acceptable only if it promises to contribute to the understanding of environmental principles or issues, fundamental biological principles, or development of knowledge that can reasonably be expected to benefit humans, animals, or the environment - Optimal standards for animal health and care result in enhanced credibility and reproducibility of experimental results - Acceptance of animal use in science critically depends on maintaining public confidence in the mechanisms and processes used to ensure necessary, humane, and justified animal use - Animals are used only if the researcher's best effort to find an alternative have failed. Researchers who use animals employ the most humane methods on the smallest number of appropriate animals required to obtain valid information

Question 96

How Do we study the Brain's structure and functions

Answer 96

-Measuring Brain and Behavior -Measuring the brain's electrical activity -Static imaging techniques ~CT MRI -Dynamic Brain imaging -Chemical and Genetic measures of brain and behavior -Comparing neuroscience research methods -Using animals in brain-behavior research

Question 97

Measuring Brain and Behavior | -neurospsychology

Answer 97

-Study of the relations between brain function and behavior -Origins ~Paul Broca discovered the link between specific damage located in the left frontal lobe region and language difficulties

Question 98

Linking Neuroanatomy and behavior

Answer 98

-Histological ~Brains sectioned postmortem and tissue stained with different dyes -Dozen of techniques and now available that allow researchers to identify molecular neurochemical, and structural differences among neuronal types

Question 99

Neuronal/Behavioral Relations

Answer 99

- Parkinson's Disease - Analysis of postmortem brain tissue showed that cells in the substantia nigra, had died - Studies showed that if the substantia nigra was destroyed, animals showed symptoms remarkably similar to those in human Parkinson's patients

Question 100

Methods of behavioral Neuroscience | -Behavioral neuroscience

Answer 100

-Study of the biological basis of behavior -Includes the study of both humans and laboratory animals -Major challenge is to develop methods for studying both normal and abnormal behavior -Ethology ~The study of animal behavior

Question 101

Methods of Behavioral Neuroscience | -Neuropsychological Testing of Humans

Answer 101

- People with damage to the temporal lobes often complain of memory disturbance - But memory is not a single function (memory for events, color, names, places and motor skills) - Rare for someone to be impaired in all forms of memory so each must be measured separately

Question 102

neuropsychological Testing of Humans | -Test of human memory

Answer 102

``` -Coris block tapping test ~Short-term recall of spatial position -Mirror drawing task ~Procedural memory -Recency memory task ~Challenges assumptions about memory ```

Question 103

methods of behavioral neuroscience | -Behavioral Analysis of rats

Answer 103

-Morris swimming task ~Place learning *Rats must find platform using external cues *Matching-to-place learning **Platform is in the same location each trial, but a different location each day *Landmark version **Platform is identified by a cue on the wall -Skilled reaching taks ~Rats are trained to reach through slot to brain food ~Movements can be broken down into segments, which are differently affected by different types of neurological perturbation

Question 104

Manipulating and measuring brain-behavior Interactions

Answer 104

-We can modify the brain and see how behavior is altered ~Two reasons for doing so *Develop hypotheses about the brain affects behavior *Test the hypotheses

Question 105

Manipulating and measuring brain-behavior Interactions | -Brain lesions

Answer 105

-Used by Karl Lashley to find location of memory in the brain -Ablation ~Removal or destruction of tissue

Question 106

Manipulating and measuring brain-behavior Interactions | -Stereotaxic Apparatus

Answer 106

-A surgical device that permits a researcher or a neurosurgeon to target a specific part of the brain for ablation

Question 107

Brain Lesions (Ablations)

Answer 107

- Lashley removed bits of cerebral cortex to study memory - Scoville removed the hippocampus from H.M. to treat epilepsy (produced amnesia) - Substantia Nigra ablated to study Parkinson's disease

Question 108

Two Types of lesions | -Electrolytic Lesion

Answer 108

- Electrode lowered into the brain at specific stereotactic coordinates - Current is passed through electrode and tissue (neurons and fibers) in the region id destroyed

Question 109

Two types of lesions | -Neurotoxic lesion

Answer 109

-A neuron-killing chemical is injected into the brain to kill only neurons- sometimes only certain types of neurons

Question 110

Manipulating and measuring brain-behavior Interactions | -Brain stimulation

Answer 110

- First used by Wilder Penfield to stimulate the cerebral cortex of humans during neurosurgery - Rats with electrodes in the lateral hypothalamus will eat whenever the stimulation is turned on

Question 111

Manipulating and measuring brain-behavior Interactions -brain stimulation ~Self-stimulation

Answer 111

-Given the opportunity, rats will press a lever to obtain the current ~Stimulation affects a neural circuit involving both eating and pleasure

Question 112

Brain Stimulation as Therapy | -Deep-brain stimulation

Answer 112

- Electrodes implanted in the brain stimulate a targeted area with a low-voltage electrical current to facilitate behavior - Used for Parkinson's, depression, OCD

Question 113

Brain stimulation as therapy | -Transcranial Magnetic Stimulation (TMS)

Answer 113

- Procedure in which a magnetic coil is placed over the skull to stimulate the underlying brain - Used either to induce behavior or ti disrupt ongoing behavior

Question 114

Optogenetics

Answer 114

- Transgenic technique that combines genetics and light to control targeted cells in living tissue - Based on the discovery that light can activate proteins - Proteins can occur naturally or can be inserted into cells - Fiber-optic light can be delivered to selective brain regions such that all neurons exposed to the light respond immediately

Question 115

Optogenetics | -ChR2

Answer 115

-When exposed to bliue light, ion channels opens and depolarize causing excitation

Question 116

Optogenetics | -NpHR

Answer 116

-A green-yellow light activates a chloride pump, hyperpolarizing the neuron can causing inhibitation

Question 117

Measuring the Brain's electrical activity

Answer 117

-Brain is always electrically active -Electrical measures of brain activity are important for studying brain functions -Four major techniques are ~Electroencephalography (EEG) ~Event-related potentials (ERP) ~Magnetonencephalography (MEG) ~Sing-cell recording

Question 118

EEG Recordings of graded potentials

Answer 118

-Measures the summed graded potentials from many thousands of neurons -Reveals features of the brain's electrical activity ~The EEG changes as behavior changes ~An EEG recorded from the cortex displays an array of patterns, some of which are rhythmical ~The living brain's electrical activity is never silent, even when the person is asleep or comatose

Question 119

Mapping brain function with event-related potentials

Answer 119

-Complex electroencephalographic waveforms related in time to a specific sensory event -To counter noise effects, the stimulus is presented repeatedly, and the recorded responses are averaged -Advantages ~Noninvasive ~Low cost -EPR record the results when a person hears a tone -ERPs can be used not only to detect which areas of the brain are processing particular stimuli but also to study the order in which different regions play a role

Question 120

Magnetoencephalography

Answer 120

-Neural activity, by generating an electrical field, also produces a magnetic fiel -Magnetic potentials recoded from detectos placed outside the skull -Permit a 3-D localization of the cell groups generating the measured field -Higher resolution the EPR -Disadvantage ~High cost

Question 121

Recoding action potentials from single cells | -Measuring single-neuron action potentials with fine electrodes

Answer 121

-Electrodes placed next to cells (extracellular recordings) in inside them (intracellular recordings)

Question 122

Recording action potentials from single cells | -Place cells

Answer 122

- Neurons maximally responsive to specific location | - Discovered in the hippocampus of rats

Question 123

Statin imaging techniques | -Computerized tomography (CT scan)

Answer 123

- X-ray beam passed through the brain at many different angles creating many different images - Images are combined with the use of computing and mathematical techniques to create a three-dimensional image of the brain

Question 124

Statin imaging techniques | -Magnetic Resonance Imaging (MRI)

Answer 124

-Technique that produces a static, three-dimensional brain image by passing a strong magnetic field through the brain, followed by a radio wave, then measuring the radiation emitted from hydrogen atoms

Question 125

Statin imaging techniques | -Diffusion tensor imaging (DTI)

Answer 125

- Detects the directional movements of water molecules to image nerve fiber pathways in the brain - Used to delineate abnormalities in neural pathways

Question 126

Statin imaging techniques | -Magnetic resonance spectroscopy (MRS)

Answer 126

- MRI method that used the hydrogen proton signal to determine the concentration of brain metabolites - Useful in detecting persisting abnormalities in brain metabolism in disorders such as concussions

Question 127

Dynamic brain imaging | -Functional magnetic resonance imaging (fMRI)

Answer 127

- When human brain activity increases, the increase in oxygen produced by increased blood flow actually exceeds the tissue's need for oxygen - Amount of oxygen in an activated brain area increases - Changes in the oxygen content of the blood alter the magnetic properties of the water in the blood

Question 128

Dynamic brain imaging | -Resting-state MRI (rs-MRI)

Answer 128

- The living brain is always active - Used to infer brain function and connectivity by studying fMRI signals when participants are "resting: (not engaged in any specific task)

Question 129

Dynamic brain imaging | -Positron Emission tomography (PET)

Answer 129

- Imaging technique that detects changes in blood flow by measuring changes in the uptake of compounds such as oxygen or glucose - Used to analyze the metabolic activity of neurons - Radioactive molecules are injected into the bloodstream - Varey expensive

Question 130

Positron Emission tomography | -Advantage

Answer 130

- Can detect the decay of hundreds of radiochemical, allows the mapping of a wide range of brain changes and conditions - Can detect relative amounts of a given neurotransmitter, the density of receptors, and metabolic activities associated with learning, brain poisoning, and degenerative processes - Widely used to stud cognitive function - Control condition (looking at a static fixation point (control)), subtracted from experimental condition (looking at a flickering checkerboard (stimulation)) - All individuals show increased blood flow in the occipital region - The difference scans are averaged the produce the representative image

Question 131

Dynamic brain imaging -Optical tomography ~Near-infrared spectroscopy (NIRS)

Answer 131

-Noninvasive technique that gathers light transmitted through cortical tissue to image blood-oxygen consumption -Advantage ~Easy to hook subjects up -Disadvantage ~Measurement restricted to cortical activity (light does not penetrate the brain very far)

Question 132

Chemical and genetic measures of brain and behavior

Answer 132

- Neurons are regulated by genes that encode the synthesis of particular proteins within cells - Genes control the cell's production of chemicals, so it is possible to relate behavior to genes and to chemicals inside and outside the cell

Question 133

Measuring the brain's chemistry | -Microdialysis

Answer 133

- Technique used to determine the chemical constituents of extracellular fluid - Semipermeable membrane is placed in the brain - Fluid flows in where it passes along the membrane - Diffusion drives the passage of extracellular molecules across the membrane - Fluid containing the molecules from the brain exits through tubing to be collected fro analysis

Question 134

Measuring the brain's chemistry | -Cerebral voltammetry

Answer 134

- A small carbon fiber electrode and a metal electrode are implanted in the brain - Small current is passed through the metal electrode - Current causes electrons to be added to or removed from the surrounding chemicals - Changes can be translated into a measure of extracellular levels of specific neurotransmitters that are measured as they occur

Question 135

Measuring genes in brain and behavior

Answer 135

- Variations in gene sequences contribute to brain organization - Studying twins and adopted children allows us to tease apart environmental and genetic contributions to behavior - We can also relate the alleles of specific genes to behaviors

Question 136

Measuring genes in brain and behavior | -Brain-derived neurotrophic factor (BDNF)

Answer 136

-Plays important role in stimulating neural plasticity -Gene related to BDNF has two alleles ~Val 66 MET ~Val 66Val

Question 137

Measuring genes in brain and behavior | -Bueller and colleagues

Answer 137

-The MET allele is associated with an 11% reduction in hippocampal volume, and poorer memory for specific events (episodic memory)

Question 138

Epigenetics

Answer 138

-Genes that are expressed can change dramatically in response to environment and experience -Persis throughout a lifetime and even across multiple generations -Wide range of experiential factor ~Chronic stress, traumatic events, drugs, culture, disease ~Cumulative experiences affect how genes work

Question 139

Epigenetics | ~Fraga and colleagues

Answer 139

-Twins have nearly identical patterns of gene expression early in life, but remarkably different by age 50

Question 140

Epigenetics | -Szyf, Meaney, and colleagues

Answer 140

-Amount of maternal attention given to newborn rat pups alter gene expression in their adult hippocampus

Question 141

Using animals in brain-behavior research | -Two important issues

Answer 141

- Do animals actually contract the same neurological diseases that humans do? - How ethical is it to use animals in research?

Question 142

Benefits of creating animal models of disease

Answer 142

-Some disorders are easy to model (stroke) -Behavioral disorders are more difficult ~Attention-deficit/hyperactivity disorder (ADHD) *Developmental disorder characterized by core behavioral symptoms if impulsivity hyperactivity, and/or inattention

Question 143

Benefits of creating animal models of disease | -Kyoto SHR rats

Answer 143

- Proposed as a good model for ADHD - Known abnormalities in prefrontal dopaminergic innervation that correlate with behavioral abnormalities such as hyperactivity - Dopamine agonists such as methylphenidate (Ritalin) can reverse behavioral abnormalities, but in children with ADHD and in SHR rats

Question 144

Animal Welfare and scientific experimantation

Answer 144

- Most governments regulate the use of animals in research - Universities and other research organizations have additional rules governing animal use - Legislation concerning the care and use of laboratory animals in the US is set forth in the Animal Welfare Act - In addition, the NHI administers the Heath Research Extension Act - All accredited North American universities that receive government grant support are required to provide adequate treatment for all vertebrate animals - Considerable controverts remain over using animals in scientific research - The debate centers on issues of law, morals, customs, and biology - Because you, as a student, encounter many experiments on animals in this course, these issues are important to you as well

Question 145

Guidelines of the Canadian Council on Animal Care

Answer 145

- The use of animals in research, teaching, and testing is acceptable only if it contributes to the understanding of environmental principles, or development of knowledge that can reasonably be expected to benefit humans, animals, or the environment - Optimal standards for animal heath can care can result in enhanced credibility and reproducibility of experimental results - Acceptance of animal use in science critically depends on maintaining public confidence in the mechanisms and processes used to ensure necessary, human, and justified animal use - Animals are used only if the researcher's best efforts to find an alternative have failed. Researchers who use animals employ the most humane methods on the smallest number of appropriate animals required to obtain valid information