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Chapter 5: Methods and Strategies of Research 5.1 Multiple Choice 1) The standard drug treatment for angina pectoris involves ________ administration of ________. A) topical; amphetamine B) rectal; a benzodiazepine C) intravenous; nitroglycerine D) sublingual; nitroglycerine E) topical; L-DOPA Answer: D Rationale: The standard drug treatment for angina pectoris involves angina administration of nitroglycerine. 2) The key problem noted in Balint's syndrome is A) difficulty in visual perception. B) making errors in naming objects and colors. C) difficulty in understanding the emotional content of speech. D) a slow, clumsy gait. E) difficulty breathing and chest pain. Answer: A 3) Which of the following is true of the experimental ablation technique? A) Ablation is a new molecular method used in neuroscience. B) Early ablation studies used focused magnetic waves to destroy brain tissue. C) The technique involves destroying brain tissue and then observing subsequent behavior. D) Ablated tissue is suctioned from the brain. E) Ablation generates results that are easily interpreted. Answer: C Rationale: The technique involves destroying brain tissue and then observing subsequent behavior. 4) One of the oldest methods used in neuroscience to study brain function is A) immunocytochemistry. B) stereotaxic surgery. C) autoradiography. D) experimental ablation. E) the study of twins. Answer: D 5) The key rationale for lesion studies is that A) the change in behavior that follows a brain lesion can give important clues about a function of an ablated brain area. B) lesions are simple to create within the brain. C) brain lesions are specific for fibers of passage. D) brain lesions reliably produce marked and observable changes in behaviors. E) most lesions are temporary. Answer: A Rationale: The key rationale for lesion studies is that the change in behavior that follows a brain lesion can give important clues about a function of an ablated brain area. 6) The key difference between function and behavior is that circuits within the brain perform A) independent behaviors. B) a single behavior that is functional for the organism. C) reflexes that are inhibitory. D) a function that contributes to a behavior. E) All of the above are correct. Answer: D Rationale: The key difference between function and behavior is that circuits within the brain perform. 7) Which of the following represents a problem for interpreting the effects of a brain lesion on behavior? A) It is difficult to reliably monitor animal behavior. B) No one circuit is solely responsible for a behavior. C) Brain lesions are difficult to produce in animals. D) Brain structures are functionally isolated from each other. E) Human observations are too unreliable. Answer: B Rationale: Because no one circuit is solely responsible for a behavior, it can be difficult to interpret the effects of a brain lesion on behavior. 8) A lesion technique that is selective for cell bodies in brain tissue involves A) aspiration of tissue using a pipette. B) overstimulation of glutamate receptors by kainic acid. C) the flow of alternating current at the tip of an electrode. D) the flow of electrical current through an electrode. E) infusion of hypertonic saline through a cannula. Answer: B Rationale: A lesion technique that is selective for cell bodies in brain tissue involves overstimulation of glutamate receptors by kainic acid. 9) Imagine that feeding behavior was eliminated when a radio-frequency lesion was used to damage the lateral hypothalamus of a rat, which suggested that cells within this region initiate feeding. If a subsequent study failed to observe a change in feeding after injection of kainic acid into the lateral hypothalamus, what conclusion would be appropriate? A) The lateral hypothalamus functions to inhibit eating. B) The changes in eating noted in the first study may be due to damage to axon fibers that are passing through the lateral hypothalamus. C) The changes in eating are due to damage to cell bodies within the lateral hypothalamus, and these act to initiate eating. D) Glial cells within the lateral hypothalamus are key for the control of eating. E) Cannot draw a conclusion based on this study. Answer: B Rationale: If a radiofrequency lesion of a brain area alters feeding but kainic acid injected into the same brain region did not, the changes in eating noted in the first study may be due to damage to axon fibers that are passing through the lateral hypothalamus. 10) Which of the following techniques creates a brain lesion by overstimulating neurons to death? A) aspiration of a region of the cortex B) extreme physical exercise C) infusions of an excitatory amino acid into a brain region D) 6-hydroxydopamine infusions into a brain region E) radio-frequency current passed through a brain region Answer: C 11) Infusion of ________ into brain tissue overstimulates _______, thereby ablating cell bodies. A) PCP; NMDA receptors B) kainic acid; glutamate receptors C) 6-hydroxydopamine; NMDA receptors D) PCP; D2 receptors E) THC; CB2 receptors Answer: B Rationale: Infusion of kainic acid into brain tissue overstimulates glutamate receptors, thereby ablating cell bodies. 12) A key advantage of ________ lesions is that they affect only neural cell bodies and do not damage axons passing through the region. A) aspiration B) sub-cortical C) radio-frequency D) 6-hydroxydopamine E) excitotoxic Answer: E Rationale: A key advantage of excitotoxic lesions is that they affect only neural cell bodies and do not damage axons passing through the region. 13) An experimenter wishes to determine the effect of a radio frequency lesion placed in the lateral hypothalamus on emotional behavior in the rat. In order to be able to attribute any changes in emotional behavior to the lesion, this experiment will require a(n) A) sham lesion control group. B) current source. C) aspiration device. D) cooling electrode. E) stereotaxic instrument. Answer: A Rationale: A sham lesion control group is required to interpret the results of a brain lesion study. 14) A temporary disruption of neural activity in a local brain region can be produced A) using an injection of kainic acid into the region. B) using an injection of muscimol into the region. C) by local heating of the region using a cryoloop. D) by injection of a GABA antagonist into the region. E) by infusion of a low dose of ethanol into the region. Answer: B Rationale: A temporary disruption of neural activity in a local brain region can be produced using an injection of muscimol into the region. 15) A key advantage of a reversible brain lesion is that A) axons of passage are not affected by reversible procedures. B) each animal can serve as its own control. C) cell bodies are not affected by reversible procedures. D) such lesions affect brain tissue near the tip of the lesion device. E) the method does not damage adjacent glial cells. Answer: B Rationale: A key advantage of a reversible brain lesion is that each animal can serve as its own control. 16) The ________ is a device that holds an animal’s head fixed in space and that can be used to implant an electrode or cannula into brain. A) cryoloop B) electroencephalogram C) stereotaxic apparatus D) macroelectrode assembly E) ocular apparatus Answer: C 17) ________ is a skull landmark which also serves as a reference point for stereotaxic surgery. A) Lambda B) The optic chiasm C) Bregma D) The junction of the parasagittal sutures E) The zero point Answer: C 18) The three numbers listed on a page of a stereotaxic atlas describe A) the location of a brain structure in three planes relative to bregma. B) the current settings required to produce an electrolytic lesion. C) the settings on a stereotaxic apparatus for mice versus rats versus hamsters. D) the strain, age, and weight of an animal. E) the amounts of repeated drug doses required to produce a functional lesion Answer: A Rationale: The three numbers listed on a page of a stereotaxic atlas describe the location of a brain structure in three planes relative to bregma. 19) In surgery that uses the stereotaxic instrument, A) the head holder is designed to fix the skull in a rigid position. B) the carrier arm can be manipulated in two dimensions. C) stereotaxic surgery does not require coordinates from a brain atlas. D) the procedure is limited to the creation of brain lesions. E) Stereotaxic surgery is limited to animals. Answer: A 20) Stereotaxically guided lesions in humans have been used to treat A) Alzheimer's disease. B) Parkinson's disease. C) Balint's syndrome. D) angina pectoris. E) schizophrenia. Answer: B Rationale: Stereotaxically guided lesions in humans have been used to treat Parkinson's disease. 21) After death, ________ enzymes have the effect of ________ brain tissue. A) microbial; fixing B) microbial; hardening C) autolytic; dissolving D) mold; preserving E) autolytic; preserving Answer: C Rationale: After death, autolytic enzymes have the effect of dissolving brain tissue. 22) ________ is the histological procedure in which a brain is placed in a formalin solution to halt autolysis and decomposition. A) Autoradiography B) Perfusion C) Fixation D) Staining E) Exsanguination Answer: C 23) Formalin is useful in histology because it A) softens the brain tissue for slicing. B) halts the enzyme process that breaks down brain tissue after death. C) quickly removes blood from the gut. D).stains for neuron nuclei. E) bleaches the brain tissue. Answer: B 24) Which of the following does not belong with the other four? A) producing a lesion within the brain B) visual examination of a stained section C) cutting the brain D) staining the brain E) fixation of the brain Answer: A Rationale: Producing a brain lesion is distinct from the other terms which involve histology. 25) A ________ is an instrument used to slice the brain into thin pieces that can be preserved on a glass slide. A) microtome B) stereotaxic C) cry knife D) histotome E) microscope Answer: A 26) A thin slice of brain tissue created by a microtome is often referred to as a brain A) fragment. B) cut. C) section. D) view. E) segment. Answer: C 27) The fine details of neuron structure in a brain section can be revealed by A) bathing the section in mounting medium. B) immersing the tissue in a stain that dyes neuron components. C) immersion in xylene. D) fixation in albumin. E) visual examination of the raw brain section under a microscope. Answer: B Rationale: The fine details of neuron structure in a brain section can be revealed by immersing the tissue in a stain that dyes neuron components. 28) The RNA, DNA, and associated proteins in cell bodies that are dyed by certain stains are collectively referred to as A) cytoplasm. B) amino acids. C) Nissl substance. D) gangliosides. E) nucleotides. Answer: C 29) Dyes such as cresyl violet are useful for staining A) dying neurons. B) axons of passage. C) glial cells. D) newly formed neurons. E) cell bodies. Answer: E Rationale: Dyes such as cresyl violet are useful for staining cell bodies. 30) The most commonly used stain for identifying nuclear masses in brain sections is A) 6-hydroxydopamine. B) cresyl violet. C) methylene blue. D) PHA-L. E) formaldehyde. Answer: B 31) Which of the following is a problem for the use of a microscope in the examination of brain tissue? A) A light microscope cannot resolve fine synaptic details such as synaptic vesicles. B) A light microscope can magnify an image up to X1500, which is sufficient to view some details such as synaptic vesicles. C) Beams of electrons passed through a thin brain section cast a dark shadow on photographic film. D) A light microscope shows better resolution than does an electron microscope. E) A light microscope shows three-dimensional details, which makes for a more difficult histological analysis. Answer: A Rationale: A light microscope cannot resolve fine synaptic details such as synaptic vesicles. 32) Which of the following is true of the use of microscopes in histology? A) Scanning electron microscopes are used to generate PET scan images. B) A light microscope can magnify an image up to X1500, which is sufficient to view some neuron details such as synaptic vesicles. C) A light microscope can resolve fine synaptic details such as synaptic vesicles. D) A scanning electron microscope shows better resolution than does an electron microscope. E) A scanning electron microscope shows three-dimensional details in nerve tissue. Answer: E Rationale: A scanning electron microscope shows three-dimensional details in nerve tissue. 33) Which of the following techniques would be used to trace efferent axons from a brain region to other brain regions? A) a retrograde labeling method B) staining produced by cresyl violet C) fluorogold D) an anterograde labeling method E) computerized tomography Answer: D Rationale: The anterograde labeling techniques would be used to trace efferent axons from a brain region to other brain regions. 34) The most commonly used method for tracing efferent axons connections involves the infusion of ________ into a brain region. A) fluorogold B) cresyl violet C) methylene blue D) PHA-L E) formalin Answer: D 35) A common use of PHA-L, a lectin found within kidney beans, is to A) preserve brain tissue. B) stain cell bodies. C) degrade acetylcholine molecules. D) localize the target of neural efferents. E) localize the source of neural afferents. Answer: D Rationale: A common use of PHA-L, a lectin found within kidney beans, is to localize the target of neural efferents. 36) Which of the following is true of the anterograde labeling procedure? A) A target molecule is injected into the blood stream. B) The target molecule is transported from the axon terminals back to the soma and dendrites. C) The target molecule is taken up by the glial of cells in the injection zone. D) Eventually most regions of the cell are filled with the target molecule. E) A light microscope is used to visualize the cells in a section that contain the target molecules. Answer: B Rationale: In the anterograde labeling method, the target molecule is transported from the axon terminals back to the soma and dendrites. 37) Immunocytochemistry techniques take advantage of the specific affinity of antibodies for A) a neurotransmitter receptor. B) nerve cell nuclei. C) cytogens. D) a peptide or protein molecule. E) white blood cells. Answer: D Rationale: Immunocytochemistry techniques take advantage of the specific affinity of antibodies for a peptide or protein molecule. 38) Which labeling method uses chemicals that are taken up by dendrites or cell bodies and subsequently transported through axons toward terminal buttons? A) heterograde B) axoplasmic C) anterograde D) retrograde E) homeostatic Answer: C 39) ________ are produced by white blood cells to destroy invading microorganisms in the body. A) Antibodies B) Autogens C) Antigens D) Receptors E) Autophagins Answer: A 40) Which labeling method identifies the inputs to a brain region? A) a retrograde labeling method B) an electrolytic lesion study C) an anterograde labeling method D) microdialysis E) computed tomography Answer: A Rationale: The retrograde labeling method identifies the inputs to a brain region. 41) Which chemical is used to trace afferent axons? A) formalin B) cresyl violet C) methylene blue D) fluorogold E) PHA-L Answer: D 42) Efferent is to afferent as A) formalin is to cresyl violet. B) PHA-L is to fluorogold. C) staining is to formalin. D) fluorogold is to PHA-L. E) a light microscope is to immunocytochemistry. Answer: B Rationale: Efferent is to afferent as PHA-L is to fluorogold. 43) The pseudorabies virus is useful A) for the tracing of efferent fibers. B) for the tracing of afferent fibers. C) because it labels cells that have died from overstimulation. D) for the tracing of serial synaptic connections. E) in that this virus only affects nerve cells outside the brain and spinal cord. Answer: D 44) Study of the function of the living human brain is difficult because A) it is difficult to induce brain damage in humans.. B) brain damage is uniform from case to case. C) the human brain is too large to provide a fine detail image. D) researchers have to wait for the natural death of a brain-damaged human to verify the location of the brain damage. E).light microscopes cannot resolve fine detail in human brains. Answer: D Rationale: Study of the function of the living human brain is difficult because researchers have to wait for the natural death of a brain-damaged human to verify the location of the brain damage. 45) The first technique used to visualize a living human brain was that of A) computerized tomography. B) microdialysis. C) magnetic resonance imaging. D) single-unit recording. E) PET scans. Answer: A 46) The ________ technique uses X-rays to generate an image of the living human brain. A) EEG B) microdialysis C) magnetic resonance imaging D) computerized tomography scanning E) PET scanning Answer: D 47) Light microscope images are to electron microscope images as A) PET scans are to CT scans. B) immunocytochemistry procedures are to FOS procedures. C) CT scans are to MRI scans. D) MRI scans are to light microscope slides. E) MRI scans are to CT scans. Answer: C Rationale: Light microscope images are to electron microscope images as CT scans are to MRI scans. 48) Which of the following is true of MRI scans? A) MRI was the first method used to visualize the living human brain. B) MRI scans can only view the horizontal plane. C) MRI scans show greater spatial resolution than do CT scans. D) MRI scans involve the integration of X-ray beams passed through the head. E) MRI scans show less detail than do CT scans. Answer: C 49) Which technique uses a radiofrequency wave to excite hydrogen atoms in the brain to generate an image of the living human brain? A) computerized tomography B) microdialysis C) magnetic resonance imaging D) single-unit recording E) PET scans Answer: C 50) The ______ procedure allows for the labeling of ______ in the living human brain. A) diffusion tensor imaging; collections of cell bodies B) CAT scan; axons C) diffusion tensor imaging; bundles of axons D) CAT scan; dendrites E) light microscope scan; vesicles Answer: C 51) Which of the following is true of acute recording studies of rat brain electrical activity? A) Such studies are done under anesthesia. B) The rat must recover from the anesthesia before the start of recordings. C) Acute studies focus on motor function. D) Acute studies focus on memory function. E) These recordings are subject to movement artifacts.. Answer: A 52) Single-unit recordings A) are made using macroelectrodes placed on the skull surface. B) represent summated neural activity of many neurons. C) indicate that serotonergic neuron activity is silent during REM sleep. D) do not require elaborate amplifiers and equipment. E) suggest that serotonin-containing neurons excite REM sleep. Answer: C Rationale: Single-unit recordings indicate that serotonergic neuron activity is silent during REM sleep. 53) A(n) ______ might be used to record the electrical activity of a single nerve cell in an animal brain. A) microdialysis probe B) macroelectrode C) scanning electron microscope D) microelectrode E) micromyograph Answer: D 54) The source of the electrical potentials recorded from the scalp of a subject is A) the natural flow of electrical current along the outer cell layers of skin. B) the signals generated by the contraction of muscle fibers that lie under the scalp. C) the summated activity of nerve cell action potentials and postsynaptic potentials. D) the signals generated by the activity of the sweat glands in response to stressors. E) movement of ions generated by magnetic currents. Answer: C 55) Macroelectrodes implanted into human brain are most commonly used A) to destroy brain tissue. B) to locate spiking brain tissue in epileptic patients. C) to control thought patterns. D) for the diagnosis of Parkinson's disease. E) to treat Balint's syndrome. Answer: B Rationale: Macroelectrodes implanted into human brain are most commonly used to locate spiking brain tissue in epileptic patients. 56) The firing rates of ________ neurons and of ________ neurons fall to zero during REM sleep. A) noradrenergic; serotonergic B) cholinergic; dopaminergic C) GABA; adenosine D) cholinergic; adenosine E) opioid; dopaminergic Answer: A 57) A(n) ________ involves a motor that drives long paper sheets under a set of ink pens.. A) tricorder B) autoradiograph C) polygraph D) CT scanner E) XY recorder Answer: C 58) The ________ is a device that takes advantage of the changing magnetic fields produced by the electrical activity of the brain to produce a record of neural activity in the awake brain. A) neuromagnetometer B) magnetic resonance imaging scanner C) electroencephalograph D) transcranial magnetic stimulator E) micromyograph Answer: A 59) EEG recordings are useful for A) monitoring muscle function during brain surgery. B) the diagnosis of epilepsy. C) the study of sexual motivation. D) the study of memory and learning. E) Recording eye movements during sleep. Answer: B 60) Which technique takes advantage of the requirement of glucose for more fuel? A) neuromagnetometer B) microdialysis C) electroencephalograph D) c-FOS E) 2-DG autoradiography Answer: E 61) The metabolic activity of a specific region of the living rat brain can be revealed by A) MRI scans. B) CT scans. C) autoradiography of ghrelin concentration. D) measurement of Fos protein concentration. E) EEG recordings. Answer: D Rationale: The metabolic activity of a specific region of the living rat brain can be revealed by measurement of Fos protein concentration. 62) Which technique uses photographic emulsions to record the activity of discrete cells in the brain? A) neuromagnetometer B) microdialysis C) electroencephalograph D) c-FOS E) 2-DG autoradiography Answer: E 63) Measurements of the relative activity of immediate early genes is useful in that A) these genes rarely change their activity level. B) immediate early genes fluoresce when active. C) immediate early genes control glucose utilization. D) the presence of an early gene product in the cell nucleus is a marker of neuron activation. E) one can trace circuits of serial activation. Answer: D Rationale: Measurements of the relative activity of immediate early genes is useful in that the presence of an early gene product in the cell nucleus is a marker of neuron activation. 64) ______ is an immediate early gene product that is increased during neural ______. A) PHL; inactivation B) Fos; activation C) PHL; activation D) Fos; inactivation E) 2-DG; inactivation Answer: B 65) Which of the following is true of the fMRI technique? A) The fMRI technique has a lower spatial resolution than does the CT scan. B) The PET scan has a better spatial resolution than does the CT scan. C) The fMRI technique is based on the rapid acquisition of multiple PET scans. D) fMRI scans have a better spatial resolution than do PET scans. E) fMRI scans require days to complete. Answer: D 66) The primary disadvantage of the PET scan technique relates to A) the operating cost of the scanner. B) the long half-life of the radioactive 2-DG molecule. C) the inherent danger posed by the technique. D) an inability of the technique to assess changes in metabolic activity. E) the fact that the technique can measure neuron volume, but not activity. Answer: A Rationale: The primary disadvantage of the PET scan technique relates to the operating cost of the scanner. 67) A key advantage of the fMRI technique is that the method can A) record the electrical activity of brain. B) induce the secretion of neurotransmitters from neurons. C) record the neural activity of particular brain regions. D) localize receptors in brain. E) electrically stimulate neurons. Answer: C 68) The _______ is an example of a functional imaging technique. A) fMRI scan B) magnetocephalogram C) EEG recording D) CAT scan E) MRI scan Answer: A 69) A major advantage of the PET scan method is that A) PET scans are inexpensive to conduct. B) PET scans have a higher spatial resolution than do fMRI scans. C) PET scans can localize any radioactive substance. D) PET scans can be recorded either acutely or over weeks. E) PET scanners are portable and can be taken to remote research sites. Answer: C Rationale: A major advantage of the PET scan method is that PET scans can localize any radioactive substance. 70) Which of the following procedures can be used to activate neurons? A) transcranial magnetic stimulation B) radio frequency stimulation C) fMRI scans D) chemical stimulation using glutamate E) detection of glycine using a cannula.. Answer: D 71) A major advantage of chemical stimulation using glutamate infusion is that A) it activates cell bodies but not axons. B) it is a less complicated procedure than is electrical stimulation. C) it only activates neurons in cortex. D) it activates axons, but not cell bodies. E) dendrites are inactivated by the technique. Answer: A Rationale: A major advantage of chemical stimulation using glutamate infusion is that it activates cell bodies but not axons. 72) Kainic acid is a neurotoxin as well as an activator of neurons because A) at low doses it destroys neurons. B) at low doses it dissolves the neuron membrane. C) at high doses it overexcites and then kills neurons. D) kainic acid is toxic to glial cells that nourish neurons. E) it blocks membrane sodium channels. Answer: C 73) Which of the following is true of the interaction of magnetic fields and brain function? A) Neuronal activity results in magnetic field changes. B) Sensors can detect magnetic fields in the brain. C) Magnetic fields can be used to inactivate neuronal activity. D) The effects of transcranial magnetic stimulation are similar to those of direct electrical stimulation of exposed brain tissue. E) All of the above are correct. Answer: E 74) The ______ technique takes advantage of the fact that a particular _____ can open voltage-gated ion channels. A) optogenetic; light B) photoxicity; light C) TMS; light D) optogenetic; form of glutamate E) photostimulation; magnetic wave Answer: A 75) A transmitter such as acetylcholine can be localized in brain by A) immunocytochemistry. B) detecting the enzyme that produces acetylcholine. C) low-performance liquid chromatography. D) CT scans. E) transcranial magnetic stimulation. Answer: B 76) A drug that inhibits ______ would be expected to ______. A) acetylcholine; produce hallucinations B) choline acetyltransferase; produce hallucinations C) acetylcholinesterase; produce hallucinations D) acetylcholine; improve memory E) acetylcholinesterase; prevent hallucinations Answer: C Rationale: A drug that inhibits acetylcholinesterase would be expected to produce hallucinations. 77) Peptides or proteins can be localized in brain using A) immunocytochemistry. B) microiontophoresis. C) in situ hybridization. D) high-performance liquid chromatography. E) microdialysis. Answer: A 78) Which of the following methods can be used to detect a certain class of receptors in the brain? A) in situ hybridization B) microdialysis C) immunocytochemistry D) microiontophoresis E) optogenetic Answer: C Rationale: The immunocytochemistry method can be used to detect a certain class of receptors in brain. 79) A key advantage of the microdialysis technique is that A) it can easily be used in humans. B) it offers the ability to sample transmitter substances in a living, conscious organism. C) it uses radioactive molecules that break down quickly. D) it can assess brain function on a moment-by-moment basis. E) the technique requires the use of powerful computers to monitor human brain function. Answer: B Rationale: A key advantage of the microdialysis technique is that it offers the ability to sample transmitter substances in a living, conscious organism. 80) Damage to dopamine neurons in the human brain can be detected using A) autoradiography of 2-DG concentrations in the nucleus accumbens. B) microdialysis of dopamine concentrations in the caudate nucleus. C) PET scans of radioactive L-DOPA concentrations in the basal ganglia. D) CT scans of the frontal cortex. E) fMRI studies of the mesolimbic dopamine system. Answer: C Rationale: Damage to dopamine neurons in the human brain can be detected using PET scans of radioactive L-DOPA concentrations in the basal ganglia. 81) Twins that share a particular trait are said to be ________ for the trait. A) concordant B) discordant C) dissimilar D) similar E) heterozygous Answer: A 82) Which of the following have identical genotypes? A) monozygotic twins B) dizygotic twins C) fraternal twins D) first cousins E) adopted siblings Answer: A 83) Which of the following is strong evidence for a genetic contribution to a behavior? A) Dizygotic twins have a higher concordance rate than do monozygotic twins. B) Monozygotic twins have a higher concordance rate than do dizygotic twins. C) Heterozygotic twins have a lower concordance rate than do monozygotic twins. D) Adopted children resemble their adopted families with regard to a trait. E) None of the above are correct. Answer: B Rationale: The observation that monozygotic twins have a higher concordance rate than do dizygotic twins is strong evidence for a genetic contribution to a behavior. 84) Which of the following is strong evidence for an environmental contribution to a behavior? A) Adopted children resemble their biological families with regard to a trait. B) Monozygotic twins have a higher concordance rate than do dizygotic twins. C) Dizygotic twins have a lower concordance rate than do monozygotic twins. D) Adopted children resemble their adopted families with regard to a trait. E) None of the above are correct. Answer: D Rationale: The observation that adopted children resemble their adopted families with regard to a trait is strong evidence for an environmental contribution to a behavior. 85) Targeted mutations involve A) injecting chemicals that block the production of transmitters in the brain. B) inserting genes to overproduce a functional protein. C) manipulating genes to impair the production of a protein. D) the induction of random genetic mutations. E) random mutation of a gene allele.. Answer: C 86) A(n)_____ refers to one of several forms of a gene. A) mutation B) isoform C) point-mutation D) association E) allele Answer: E Rationale: An allele refers to one of several forms of a gene. 5.2 True-False 1) Ablation is the oldest neuroscience procedure. Answer: True 2) Circuits within the brain perform behaviors, not functions. Answer: False 3) Interpretation of lesion studies is complicated because brain regions are often interconnected. Answer: True 4) Lesions produced by kainic acid spare fibers of passage. Answer: True 5) Fixatives such as formalin are used to stop autolysis in brain tissue. Answer: True 6) Cresyl violet is a stain used to identify axon terminals in the brain. Answer: False 7) A scanning electron microscope shows better resolution than does an electron microscope. Answer: False 8) PHA-L (phaseolus vulgaris leukoagglutinin) is a fluorescent dye. Answer: False 9) Antigens are proteins produced by white blood cells that destroy invading microorganisms. Answer: False 10) Fluorogold is used in the retrograde tracing procedure. Answer: True 11) MRI scans provide more detailed pictures than those obtained by a CT scanner. Answer: True 12) Autoradiography and 2-DG injections are used to measure the relative metabolic activity of different brain regions. Answer: True 13) An increased number of neurons that stain for Fos would be taken to mean that the brain region containing these cells has undergone neuron activation. Answer: True 14) Large doses of excitotoxic chemicals kill neurons by stimulating them to death, whereas lower doses stimulate neurons without killing them. Answer: False 15) Activation is to inhibition as glutamate is to transcranial magnetic stimulation. Answer: True 16) Acetylcholine can be localized in brain using an immunocytochemical method. Answer: False 17) Microdialysis is used to measure the brain's secretions. Answer: True 18) Fraternal twins have identical genotypes. Answer: False 19) Identical twins share 100 percent of their genes whereas fraternal twins share, on average, about 50 percent of their genes. Answer: True 5.3 Short-Answer Essay 1) Explain the rationale for experimental ablation studies. Answer: The changes in behavior noted after removal of brain tissue can be related to the function of that brain region. 2) Explain the distinction between "function" and "behavior." Answer: Circuits within the brain control functions rather than discrete behaviors. Any one behavior may involve the activity of multiple brain areas. 3) Explain what is meant by the term “excitotoxin.” Answer: An excitotoxin, such as kainic acid, kills neurons through overstimulation. 4) Describe a procedure that could be used to produce a reversible lesion. Answer: Reversible lesions can be produced by injection into a discrete brain region of a local anesthetic, or of muscimol (which stimulates GABA, an inhibitory transmitter). 5) Explain how and why the brain is preserved during the histology process. Answer: The brain is perfused to remove blood from the tissue and is fixed in formalin to harden the tissue and to halt autolysis. 6) Explain how neuroscientists trace the efferent connections of a brain region. Answer: A solution of PHA-L is injected into a brain region, where it is taken up by dendrites and transported to the axon terminals. After a few days, the brain of the animal is processed, using an immunocytochemical method to localize PHA-L molecules in the axon terminals. Because the axon terminals are the end point of an efferent connection, distant regions that contain nerve cells that contain PHA-L are connected with the site of injection. 7) Explain how retrograde labeling is used to trace the afferent connections for a brain region. Answer: Fluorogold is infused into the region, taken up by axon terminal buttons, and transported toward the cell body. Under the appropriate light source, a section of brain tissue containing fluorogold will fluoresce. 8) Explain how autoradiography can be used to measure the activity of brain cells. Answer: Brain cells require glucose as fuel for activity. 2-DG , like glucose, is taken up into neurons, but cannot be used for energy. If a radioactive version of 2-DG is injected into an animal, radioactive 2-DG molecules will accumulate in brain as a function of the relative activity of those cells. Autoradiography will reveal the presence of radioactive molecules in the brain, with a more intense signal in regions that were more active, and a less intense signal in less active regions. 9) Explain why chemical stimulation is sometimes preferred over electrical stimulation. Answer: Chemical stimulation can be used to excite cell bodies rather than both cell bodies and axons of passage. 5.4 Essay 1) Give an overview of stereotaxic surgery for the purpose of implanting a cannula into the brain. Answer: The target of the cannula is decided upon and located in a stereotaxic atlas. The coordinates for placement involve distances in mm from bregma (skull landmark), the midline, and beneath the surface of the skull. A stereotaxic instrument is used to hold the head of an anesthetized rat solidly in place. After incising and retracting the scalp, a hole is drilled through the skull and the cannula inserted into the brain, just above the target site. Dental acrylic and small metal screws are used to hold the cannula in place. 2) Explain how a sample brain is processed during the histology process. Answer: The brain is perfused to remove blood from the tissue and is fixed in formalin to harden the tissue and to halt autolysis. Stains are applied to the section to reveal the internal details of the brain section. 3) Provide an overview of how immunocytochemistry techniques are used for the localization of neurotransmitter receptors in brain. Answer: Antibodies are proteins produced by white blood cells that are specific to another protein or peptide (antigen). Receptors are comprised of proteins (antigens), for which an antibody can be developed and tagged using a marker such as a fluorescent marker (or dye). A slice of brain tissue is incubated with the antibody/marker so that the antibody will attach to the antigen (receptor) with each location indicated by the presence of a fluorescent signal. 4) Compare the twin method with the adoption method for the purpose of assessing the contribution of genes versus environment. Answer: The twin method identifies identical and fraternal twins and assesses the degree of similarity (concordance) between the pairs. Identical twins share 100 percent of their genes, whereas fraternal twins share 50 percent of their genes. A genetic contribution would be indicated were identical twins to show a greater concordance rate for a trait than do fraternal twins. In the adoption method, a specific trait is considered in children who were adopted early in life, with the frequency of that trait in their biological parents (genetic contribution) compared with the frequency in their adopted parents (environmental contribution). Test Bank for Foundations of Behavioral Neuroscience Neil R. Carlson 9780205968091, 9780134639796, 9780205947997

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