5.2

Central nervous system axons regenerate much better in fish than in mammals because fish: a. nerves do not have to travel so far to reach their target. b. myelin does not secrete proteins that inhibit axon growth. c. nerves have so much more myelin than do mammal nerves. d. myelin secretes a protein that accelerates regeneration.

ANS: B

Diaschisis refers to the: a. increase in activity of neurons surrounding a damaged area. b. decreased activity of surviving neurons after other neurons are damaged. c. increased activity in the cerebral cortex after damage to any part of the brain. d. increased activity in the hypothalamus after damage to any part of the brain.

ANS: B

If a person suffered injury to the right motor cortex that resulted in paralysis of the left arm and later showed some evidence of recovery of function, which of the following would be a likely explanation? a. Using the right arm more strengthened the left arm. b. The left motor cortex strengthened its control over the left arm. c. New neurons grew in place of the damaged ones. d. The left arm was deafferented.

ANS: B

In dealing with brain-damaged patients, the usual goal is to: a. get the patients to rely on other people for the skills that they have lost. b. get the patients to make as much use as possible of the impaired systems. c. promote physical changes in the brain, such as collateral sprouting. d. encourage complete inactivity to enable the brain to engage in restorative processes.

ANS: B

In general, what can we say about recovery for brain-damaged patients in the future? a. There is very little hope of recovery. b. Researchers are optimistic, but they need to evaluate many possible therapies. c. Drug therapies have clear advantages over all other approaches. d. Brain grafts are the only real answer.

ANS: B

In research aimed at minimizing damage due to stroke, attempts to prevent overstimulation of cells have produced: a. very promising results. b. disappointing results. c. a complex interaction between age of patient and season of the year. d. positive results in humans, but not so for animals.

ANS: B

Investigators recorded activity from the cerebral cortex of monkeys that had an entire limb deafferented twelve years earlier. Much to their surprise, what did they find? a. The organization of this area of the cortex had not been changed at all by the operation. b. This whole cortical area had become responsive to the face. c. This whole cortical area had become response to the opposite limb. d. This whole cortical area had developed motor instead of sensory functions.

ANS: B

Ischemia and hemorrhage kill neurons by: a. understimulating them. b. overstimulating them. c. overactivating the sodium-potassium pump. d. depleting the glutamate supply available to neurons.

ANS: B

One limiting factor in the ability of damaged axons to regenerate in the brain and spinal cord is that: a. they don't have any myelin to guide them. b. they regenerate only one to two millimeters. c. growing dendrites compete with growing axons. d. there are no muscles in the brain and spinal cord to guide the growth.

ANS: B

One way to relieve the pain associated with a phantom limb is to: a. remove more of the amputated limb. b. have the amputee learn to use an artificial limb. c. stimulate that part of the cortex. d. help them understand that there is no neural basis for these sensations.

ANS: B

Sensations from phantom limbs: a. come from the stump of the amputated limb. b. are a result of brain reorganization. c. do not have a neural basis. d. can be diminished if more of the limb is removed surgically.

ANS: B

The area of the cortex that receives input from the face is adjacent to the area of the cortex that receives input from the foot. After amputation of the foot, it is possible that a phantom limb sensation will be felt whenever the: a. other foot is touched. b. face is touched. c. face is anesthetized. d. axons from the foot regrow.

ANS: B

What does edema mean? a. Lack of glucose b. Ischemia from an obstruction of an artery c. Hemorrhage of an artery d. Swelling due to accumulation of fluid

ANS: B

Which of the following is the most common cause of a stroke? a. Lack of glucose b. Ischemia from an obstruction of an artery c. Hemorrhage of an artery d. Blow to the head

ANS: B

____ cells proliferate after a stroke. a. Penumbra b. Microglia c. Ischemia d. Cancer

ANS: B

After a cut through the spinal cord, axons grow back enough to restore functioning in certain ____ but not in ____. a. adults; infants b. infants; adults c. fish; mammals d. mammals; primates

ANS: C

After damage to a set of axons, neurotrophins induce nearby: a. injured axons to form new branches. b. injured dendrites to form new branches. c. uninjured axons to form new branches. d. uninjured dendrites to form new branches.

ANS: C

Because spinal injury damages many axons, ____ develop increased sensitivity to the remaining ones. a. glia b. collateral sprouts c. postsynaptic neurons d. phantom limbs

ANS: C

Central nervous system axons regenerate much better in fish than in mammals because: a. fish nerves do not have to travel so far to reach their target. b. fewer fish nerves are covered with myelin. c. fish do not produce as much scar tissue. d. fish generally have a lower body temperature

ANS: C

Certain axons innervating a given neuron are damaged. What compensatory change is likely to take place in that postsynaptic cell? a. collateral sprouting b. removal of toxins c. denervation supersensitivity d. decrease in glucose utilization

ANS: C

Closed head injury results in damage partially because of: a. increased production of myelin. b. excessive deficit of neurotrophins. c. rotational forces that push the brain against the inside of the skull. d. infection.

ANS: C

Damage to some of the axons that innervate a given structure may give rise to: a. collateral sprouting, but not denervation supersensitivity. b. denervation supersensitivity, but not collateral sprouting. c. both collateral sprouting and denervation supersensitivity. d. neither collateral sprouting nor denervation supersensitivity.

ANS: C

Denervation supersensitivity refers to an increase in: a. production and release of neurotransmitters. b. growth of axon branches. c. responses to neurotransmitters. d. polarization of the membrane at rest.

ANS: C

If a brain area loses a set of incoming axons, we can expect some combination of ____ by the remaining axons and collateral sprouting by other axons that ordinarily attach to some other target. a. disuse supersensitivity b. decreased response c. denervation supersensitivity d. response supersensitivity

ANS: C

If a tree branch is cut, the surrounding branches may grow enough to fill in the empty space left by the missing branch. When this same type of event occurs in the nervous system following brain damage, it is called: a. hemiplegia. b. denervation supersensitivity. c. collateral sprouting. d. tree branching.

ANS: C

If findings from rat studies generalize to humans, then which of the following best describes how brain damage affects memory for a learned skill? a. It destroys the memory forever. b. The memory is not affected. c. The memory may be present, but difficult to locate. d. The old memory is lost, but new ones are easier to acquire

ANS: C

If supersensitivity takes place, what can one expect to find regarding the number of receptors? a. An increased number in the presynaptic cell b. A decreased number in the presynaptic cell c. An increased number in the postsynaptic cell d. A decreased number in the postsynaptic cell

ANS: C

In hemorrhage, cells in the penumbra: a. lose much of their oxygen. b. lose much of their glucose. c. are flooded with excess oxygen. d. act quickly to strengthen the blood-brain barrier.

ANS: C

Ischemia is to ____ as hemorrhage is to ____. a. older individuals; younger individuals b. proximal; distal c. obstruction; rupture d. barely noticeable; lethal

ANS: C

One approach in minimizing stroke damage in laboratory animals is the use of: a. calcium b. serotonin c. cannabinoids d. opioids

ANS: C

Researchers have tried using drugs that block apoptosis. Results have been: a. favorable in animals and human trials. b. favorable in animal trials but too costly to try with humans. c. favorable in animal trials but difficult or impractical to apply to humans. d. unfavorable in all research trials.

ANS: C

To promote recovery, stroke victims should be given: a. stimulant drugs immediately after the stroke. b. any drug that decreases dopamine. c. stimulant drugs a few days after the stroke. d. tranquilizers a few days after the stroke.

ANS: C

What is one impediment to regeneration of axons in the mammalian central nervous system? a. Inhibitory chemicals secreted by the damaged portion of the axon b. Bacterial infections caused by the decaying tissue c. Glia release chemicals that inhibit axon growth d. Inhibitory messages sent from the cell nucleus when an axon is damaged

ANS: C

What is one impediment to regeneration of axons in the mammalian central nervous system? a. Inhibitory chemicals secreted by the damaged portion of the axon b. Bacterial infections caused by the decaying tissue c. Large amounts of scar tissue d. Inhibitory messages sent from the cell nucleus when an axon is damaged

ANS: C

Which of the following would be the best treatment for helping someone who is suffering from a stroke caused by a blood clot? a. decrease activity of the sodium-potassium pump b. warm the brain c. administer tPA d. enhance glutamate release

ANS: C

A monkey with one deafferented limb: a. cannot control the muscles of that limb. b. moves that limb whenever it uses its contralateral limb. c. uses it spontaneously, even though the animal has lost sensation to that body part. d. does not use it, even though it can still control the muscles.

ANS: D

A sharp blow to the head resulting from an assault or trauma that does not actually puncture the brain is called a: a. stroke. b. cerebrovascular accident. c. hemorrhage. d. closed head injury.

ANS: D

After a stroke, cells in the penumbra: a. are the first to die. b. help to remove dead or dying cells in the area of damage. c. quickly become more active, compensating for the area of damage. d. may die days or weeks after a stroke.

ANS: D

After deafferenting a monkey's forelimb, it generally fails to use it because: a. the muscles are too weak. b. moving it is painful. c. they have no motor control in the limb. d. walking on three limbs is easier than moving the impaired limb.

ANS: D

Although the following methods may or may not actually work, which one would theoretically be of potential benefit to stroke victims? a. increasing activity at glutamate receptors b. opening sodium channels c. closing potassium channels d. blocking glutamate receptors

ANS: D

Following a stroke, amphetamine could help by: a. inducing apoptosis. b. blocking activity in overstimulated areas of the brain. c. blocking glutamate release. d. increasing activity in understimulated areas of the brain.

ANS: D

Heightened sensitivity to a neurotransmitter after the destruction of an incoming axon is known as: a. axon supersensitivity b. disuse supersensitivity c. enervation supersensitivity d. denervation supersensitivity

ANS: D

If most of the axons that transmit dopamine to some brain area die or become inactive, the remaining dopamine synapses become: a. less responsive. b. less easily stimulated. c. more resistant. d. more responsive.

ANS: D

If some of the axons innervating a given cell are destroyed or if they become inactive, what compensatory process takes place in the remaining presynaptic cells? a. activation of previously silent synapses b. removal of toxins c. denervation supersensitivity d. collateral sprouting

ANS: D

One reason why axons regenerate better in the peripheral nervous system of mammals than in the central nervous system is that the peripheral nervous system: a. has fewer myelinated axons. b. has glial cells that destroy scar tissue. c. maintains a temperature closer to that at which embryonic cells form. d. produces a chemical that promotes axon growth.

ANS: D

Research on laboratory animals indicates that cannabinoids are most effective if taken: a. as soon as the stroke occurs. b. within 20 minutes of the stroke. c. steadily for one month. d. shortly before the stroke.

ANS: D

Scar tissue and myelin are similar in that they both: a. secrete chemicals to restore axons. b. are produced after brain damage. c. are formed in normal development of the nervous system. d. secrete chemicals that inhibit axon growth.

ANS: D

Suppose a finger is amputated. The part of the cerebral cortex that used to respond to that finger will: a. degenerate and die. b. remain alive but forever inactive. c. be active at times when the individual would have used that finger. d. become responsive to other fingers or part of the palm.

ANS: D

The most common cause of brain damage in young people is: a. infection. b. gunshot wounds. c. stroke. d. closed head injury.

ANS: D

Tissue plasminogen activator (tPA): a. is recommended for hemorrhage. b. overstimulates glutamate receptors. c. should be administered a few days after stroke. d. is helpful in cases of ischemia.

ANS: D

To date, the most effective laboratory method minimizing the damage resulting from stroke in nonhuman animals has been to: a. use drugs which trap free radicals. b. use drugs which effect cannabinoids. c. use neurotrophins which block apoptosis. d. cool the brain.

ANS: D

What is one reason for gradual behavioral recovery from brain damage? a. Uninjured areas of the brain develop new functions to take over the ones that were lost. b. Glia cells are transformed into neurons. c. Additional myelin forms on the axons that were not destroyed. d. Postsynaptic cells deprived of input become supersensitive.

ANS: D

Which axons will regenerate to a significant degree if cut or crushed? a. Those in invertebrates but not in vertebrates b. Only those which are unmyelinated c. Those in the central nervous system but not in the peripheral nervous system d. Those in the peripheral nervous system but not in the central nervous system

ANS: D

Which of the following is not a cerebrovascular accident? a. Ischemia b. Hemorrhage c. Stroke d. Penumbra

ANS: D

Which of the following treatments would be most likely to help a patient starting several days after a stroke? a. Injecting a drug to block dopamine b. Administering tranquilizers c. Extensive bed rest d. Giving stimulant drugs combined with physical therapy

ANS: D

Who is most likely to assess the abilities of someone who has recently had brain damage? a. Neurosurgeon b. Physical therapist c. Occupational therapist d. Neuropsychologist

ANS: D

____ helps compensate for decreased axon input. a. Axon supersensitivity b. Disuse supersensitivity c. Enervation supersensitivity d. Denervation supersensitivity

ANS: D

A continuing sensation of an amputated body part is called: a. phantom limb b. ghost limb c. Neuralgia d. tingling limb

ANS: A

A cortical cell originally responded to stimulation of the middle finger. After amputation of that finger it begins responding to the second and fourth fingers. What most likely accounts for this? a. Synaptic reorganization b. Growth of completely new axons c. Altered pattern of blood vessels in the brain d. A psychotic reaction

ANS: A

A deafferented limb: a. has lost its sensory input. b. has lost its motor control. c. is an amputated limb. d. is one which an organism uses spontaneously.

ANS: A

A lesion in the hypothalamus can lead to decreased activity in the cerebral cortex, even though the cerebral cortex is undamaged. The decreased activity in the cortex because of the loss of incoming neurons is called: a. diaschisis. b. deafferentation. c. cytotoxicity. d. hyperpolarization.

ANS: A

A stroke kills neurons in two waves, first by ____ and second by ____. a. overstimulation; understimulation b. Understimulation; overstimulation c. collateral sprouting; denervation supersensitivity d. denervation supersensitivity; collateral sprouting

ANS: A

After damage to the visual cortex, a rat no longer approaches the white card it has been trained to approach. What is the evidence that the rat has not completely forgotten the task? a. It can relearn the task faster than it can learn to approach a black card. b. After a delay, it spontaneously regains the memory and approaches a white card. c. After several unreinforced sessions, it begins responding correctly. d. Its heart rate increases when looking at a white card but not when looking at a black card.

ANS: A

After damaging input to the hippocampus, collateral sprouting is associated with improvements in: a. memory. b. taste. c. vision. d. hearing.

ANS: A

After learning strengthens one set of synapses, other synapses: a. weaken. b. die. c. get stronger. d. become aroused.

ANS: A

Closed head injury is: a. the most common cause of brain damage in young adults. b. usually fatal. c. the most common cause of Korsakoff's syndrome. d. related to Alzheimer's disease.

ANS: A

Damage due to stroke caused by ischemia can be minimized by administering a drug that: a. breaks up blood clots. b. overstimulates neurons in and around the damaged area. c. increases the release of glutamate. d. slows down the sodium-potassium pump.

ANS: A

Even _____ input produces enhanced responses. a. mild b. negative c. strong d. positive

ANS: A

In some cases, ____ enables people to maintain nearly normal behavior even after losing most of the axons in some pathway. a. receptor supersensitivity b. disuse supersensitivity c. extra supersensitivity d. response supersensitivity

ANS: A

Modern methods have demonstrated that phantom limbs develop only if the relevant portion of the ____ reorganizes and becomes responsive to alternative inputs. a. somatosensory cortex b. torso c. axon d. glia

ANS: A

What is the term for the new branches that may form in uninjured axons after damage to surrounding axons? a. collateral sprouts b. bifurcations c. denervation supersensitivity d. diaschisis

ANS: A

____ occurs as a surviving axon grows a new branch to replace the synapses left vacant by a damaged axon. a. Collateral sprouting b. Degeneration supersensitivity c. Denervation supersensitivity d. Axon sprouting

ANS: A

A damaged axon: a. will never grow back. b. can grow back under certain circumstances. c. will grow back if its dendrites do also. d. will grow back only if it is myelinated.

ANS: B

A section of the somatosensory cortex ordinarily responds to the third finger of the left hand. If that finger is amputated, to what will the cells in this part of the cortex respond? a. Nothing b. The second and fourth fingers and part of the palm c. The third finger of the right hand d. The entire left hand and the entire right hand

ANS: B

A stroke caused by an artery rupturing is also known as: a. ischemia. b. hemorrhage. c. closed head injury. d. penumbra.

ANS: B

A stroke which is caused when an artery ruptures is also known as: a. ischemia. b. hemorrhage. c. closed head injury. d. penumbra.

ANS: B

After central nervous system damage, myelin: a. degenerates and dies. b. secretes proteins that inhibit axon regrowth. c. secretes proteins that enhance some regrowth of axons. d. becomes thicker in surviving axons.

ANS: B

After damage to the connections to the left hippocampus from the left entorhinal cortex, sprouts develop from the: a. left occipital cortex. b. right entorhinal cortex. c. left hippocampus. d. right hippocampus.

ANS: B

After ischemia, neurons deprived of blood: a. transform from neurons into glia. b. lose much of their oxygen and glucose supplies. c. break down the blood-brain barrier. d. increase the velocity of their action potentials.

ANS: B

After loss of sensory input from a limb, the axons representing that limb degenerate and: a. cause immediate cell death. b. leave vacant synaptic sites at several levels of the CNS. c. destroy any leftover synapses. d. cause no change in the associated neurons.

ANS: B