neuro final practice questions

What are the advantages of animals having both rods and cones, rather than just one type of photoreceptor?

Rods are very sensitive to light and thus facilitate vision in low light. Cones have very high spatial resolution (providing visual acuity) and different photopigments (allowing animals to see in color). Having both rods and cones allows animals to see and process a great variety of visual stimuli in different environments and across a broad range of light conditions.

Describe evidence that no new neurons are added to the adult mammalian neocortex.

Since nuclear weapon testing that occurred between 1955 and 1963 caused an increase in atmospheric 14C levels, neurons born during that time would incorporate a greater ratio of 14C into their nuclear DNA. Data showed that in individuals that were adults during that time, there was no increase in the concentration of 14C in neurons. Only individuals that were born during that period of increased atmospheric 14C showed elevated concentrations of 14C in their nuclei, indicating neurogenesis in humans takes place only during development, and not during adulthood.

Compare the strategies for sound localization via by neurons in the medial superior olive (MSO) versus the lateral superior olive (LSO)/medial nucleus of the trapezoid body (MNTB).

Sound localization in the MSO relies on interaural time differences for frequencies below 3 kHz. In the case of frequencies above 3 kHz, interaural intensities are responsible for sound localization via the LSO and MNTB.

List the steps in stimulus transduction, from the physical sound stimulus to the electrical signals of inner hair cells. Indicate which steps take place in the external, middle, and inner ear.

Sound waves are gathered in the external ear, and cause the tympanic membrane to vibrate. This vibration is transferred to the oval window of the cochlea via the ossicles of the middle ear. The vibration is transferred to the endolymph in the scala media to move the stereocilia of the hair cells against the tectorial membrane. This creates a shearing force that induces tip links on the stereocilia to modulate the opening of mechanoelectrical transduction channels. An influx of cations then depolarizes the cell, increasing internal Ca2+, and releasing transmitter onto the auditory nerve.

Draw the embryonic brain, subdivided into five primitive brain regions. Label the five regions on the figure, and give examples of major brain derivatives of each region. Which of these subdivisions originates from the forebrain? Midbrain? Hindbrain?

Telencephalon—Cerebral cortex, hippocampus, basal ganglia, basal forebrain nuclei, olfactory bulb Diencephalon—Thalamus, hypothalamus, optic vesicles Mesencephalon—Superior and inferior colliculi, midbrain tegmentum Metencephalon—Cerebellum and pons Myelencephalon—Medulla The telencephalon and diencephalon originate from the forebrain, the mesencephalon from the midbrain, and the metencephalon and myelencephalon from the hindbrain.

What is the audible frequency range in humans (in Hz)? What is the approximate range of human speech sounds?

The audible range in humans is 20 Hz-20 kHz. The approximate range for human speech is 2-5 kHz.

What two strategies does the auditory system use to code sound frequency?

The auditory system uses temporal coding for sounds up to approximately 3 kHz. It also utilizes label-line coding via the tonotopically organized basilar membrane.

What symptoms indicate damage to the vestibular system?

The common symptoms of vestibular damage include poor balance, diminished head and postural stability, gait deviations, altered perception of personal and extrapersonal space, difficulty visually fixating on an object while the head moves, and altered slow and fast eye movements when the head rotates.

Which perceptual qualities of sound waves are based on frequency and which are based on amplitude?

The frequency of a sound wave corresponds to pitch, while the amplitude corresponds to loudness.

Describe the tonotopy of the basilar membrane.

The geometric structure of the basilar membrane allows a traveling wave from a stimulus to reach a point of maximum displacement based on frequency. High frequencies are detected at the base of the basilar membrane, while low frequencies are detected at the apex. This gives rise to topographical mapping of frequency.

Which symptom would you expect a person with damage to the fovea to experience? a. Total blindness b. Poor peripheral vision c. Difficulty seeing large objects d. Trouble reading e. Increased sensitivity to light

Trouble reading

Describe the steps in sensory transduction in olfactory neurons.

An odorant enters the nasal cavity and binds to an odor receptor protein located on the olfactory cilia. This triggers Golf to dissociate its α subunit to activate adenylyl cyclase III (ACIII). This increases cAMP, which opens cyclic nucleotide-gated channels to permit an influx of cyclic Na+ and Ca2+ for depolarization. When this depolarization reaches the axon hillock, action potentials are generated. This signal travels to a glomerulus where it synapses on mitral cells. These mitral cells then project to the pyriform cortex for processing.

Explain the steps in phototransduction in a rod, including its resting state and what happens when a photon is absorbed.

At rest, a rod photoreceptor contains high levels of cGMP in its outer segment. The cGMP binds to cGMP-gated cation channels, keeping them open, thus maintaining a depolarized state. When a photon is absorbed, cGMP levels decrease, cGMP dissociates from the channels, and the cGMP-gated channels close. This reduces the flow of Na+ and Ca2+ into the cell. However, K+ channels remain open in the presence of light, so positive charge flows out of the cell more rapidly than it flows in, leading to hyperpolarization.

Although the roofplate and floorplate of the neural tube are transient embryonic structures, they influence the course of CNS development. Describe their role(s) and major signaling factors.

Both the roofplate and floorplate produce and secrete inductive signals that are responsible for driving appropriate cellular differentiation in the developing embryo. Roofplate: TGF/ BMP; Floor plate: sonic hedgehog

In what ways are the vestibular and auditory sense organs similar?

Both the vestibular and auditory system have elaborate set of interconnected chambers that use endolymph movement and specialized hair cells to detect stimuli.

Other than functional reorganization of intact neurons, what are the three types of repair that occur in response to damage to the nervous system?

Peripheral nerve regeneration, restoration of damaged CNS neurons, and neurogenesis.

What are some differences between photoreceptors and other sensory cells?

Photoreceptors exhibit a graded change in membrane potential in response to light instead of action potential. They also maintain a resting membrane potential around -40 mV, and they hyperpolarize in the presence of light.

In which scenario would an ON-center ganglion cell fire the most robustly? a. A small light shining in the center of the receptive field b. A light filling the center of the receptive field c. A light filling the center and surround of the receptive field d. A light filling only the surround of the receptor field e. No light shining in the receptor field

b. A light filling the center of the receptive field

Neurons in the visual cortex respond to which type of stimulus? a. Changes in luminance b. Bars or edges in a particular orientation c. Light-dark spots d. Complex and irregular shapes e. Light-dark curves

b. Bars or edges in a particular orientation

A pregnant experimental animal was treated with excess vitamin A. Which outcome would you expect to see in her offspring? a. Increased number of cells present in laminar layer 6 b. Disruption in transcriptional regulation of other inductive signals like Sonic hedgehog c. Persistence of notochord after birth d. Development of the floorplate and roofplate in abnormal locations in the neural tube e. Development of Rett Syndrome

b. Disruption in transcriptional regulation of other inductive signals like Sonic hedgehog

How would the firing rate of a person's vestibular nerve fibers change as she accelerated from zero to 40 mph in a car, and then sustained that speed? a. Firing rate would increase and remain increased until she came to a stop again. b. Firing rate would increase only while she accelerated. c. Firing rate would decrease and remain decreased until she came to a stop again. d. Firing rate would decrease only while she accelerated. e. Firing rate would increase during acceleration, then decrease below baseline while at 40 mph.

b. Firing rate would increase only while she accelerated.

A scientist creates a mouse model with dysfunctional cyclic nucleotide-gated channels in olfactory receptor neurons. Which of the following would not occur in this model? a. Dissociation of α subunit from Golf b. Influx of calcium c. Increase in cAMP d. Activation of adenylyl cyclase III e. Odorant binding to odor receptor proteins

b. Influx of calcium

Which signal is required to induce a neural crest cell to differentiate into a sensory neuron? a. Wnt b. Leukemia inhibitory factor c. Ciliary neurotrophic factor d. Pax3 e. Hox genes

b. Leukemia inhibitory factor

The notochord forms from which germ layer? a. Ectoderm b. Mesoderm c. Endoderm d. Neuroectoderm e. Telencephalon

b. Mesoderm

How do glial cells affect regeneration in the nervous system? a. They form a physical barrier in the PNS. b. They secrete antigrowth factors in the PNS. c. They infiltrate the area and clean up debris in the CNS. d. They form a pathway or conduit for the axon to regrow in the CNS. e. The secrete neurotrophins and extracellular matrix molecules in the CNS

c. They infiltrate the area and clean up debris in the CNS.

What is the main function of the ossicles? a. Reduce energy transfer to the cochlea from loud noises b. Reduce pressure in the middle ear c. Transfer vibrations from the tympanic membrane to the oval window d. Convert sound vibrations into neural impulses e. Provide cues for elevation of high frequency sound sources

c. Transfer vibrations from the tympanic membrane to the oval window

The ability of physical therapy to improve movement in once paralyzed limbs due to central nervous system damage is most likely due to a. Reorganization of other cortical regions to support the functions of the damaged region b. Neurogenesis in the damaged cortical region c. Repair of the damaged neurons d. Increase in functionality of spinal cord circuitry e. Migration of stem cells to the damaged cortical region

a. Reorganization of other cortical regions to support the functions of the damaged region

A scientist creates a TRP channel knockout mouse model for all TRP channels. These mice would not be expected to respond to which of the following tastants in their drinking water? a. Sweet, bitter, umami, sour b. Sweet, salty c. Salty, bitter d. Umami, sour, salty e. Umami, bitter, sour, salty

a. Sweet, bitter, umami, sour

A patient is diagnosed with a bilateral lesion to the subventricular zone. What other brain area would be affected by this lesion? a. The olfactory bulb b. The amygdala c. The hippocampus d. The cerebellum e. The retina

a. The olfactory bulb

Which structure(s) connect(s) adjacent stereocilia? a. Tip links b. Kinocilium c. Inner hair cells d. Outer hair cells e. Microtubules

a. Tip links

A transection occurs at the base of the brain stem severing descending spinal inputs. What is one possible treatment that could benefit axonal regrowth? a. Use a peripheral nerve graft to bridge axons above and below the injury. b. Use a central nerve graft to bridge axons above and below the injury. c. Do nothing; innate processes exist that will lead to significant regeneration. d. Use a pharmacological blockade of Bcl2 in the damaged region. e. Treat with a drug that enhances the immune response

a. Use a peripheral nerve graft to bridge axons above and below the injury.

A human's perception of pitch corresponds to the _______ of a sound wave; perception of loudness corresponds to the _______ of a sound wave. a. frequency; amplitude b. amplitude; frequency c. waveform; amplitude d. amplitude; phase e. phase; waveform

a. frequency; amplitude

A(n) _______ would be least likely to show a change in behavior in response to species-specific pheromones. a. human b. tiger c. rat d. ant e. moth

a. human

A 500-Hz signal from a speaker located to the left of a study participant will reach its target neuron in the ______ superior olive from the left ear _______ compared to the same neuron from the right ear. a. medial; sooner b. medial; later c. medial; at the same time d. lateral; sooner e. lateral; later

a. medial; sooner

How might Hebb's postulate account for the formation of ocular dominance columns?

Hebb's postulate states that synapses with correlated activity patterns will strengthen while other connections will weaken, establishing competition between inputs. Ocular dominance columns are formed when input from one eye successfully innervates a neuron while input from the other eye retracts from that neuron but successfully innervates a neuron elsewhere, all due to competitive interaction.

Are individual odors recognized by a labeled line strategy or by computing the activity from ensembles of neurons? Which system is involved in recognition of tastes?

Individual odors are recognized by computing the activity from ensembles of neurons, whereas tastes are recognized by labeled line coding.

Why is light adaptation in the retina so important, and what does it involve?

Light adaptation occurs when photoreceptors decrease their sensitivity as illumination increases. This prevents the receptors from saturating, and it extends the range of light intensities that they can respond to.

What features of the olfactory system make it highly sensitive to low concentrations of odorants?

Low concentrations of odorants are detectable due to the high degree of convergence in the olfactory system. Many olfactory axons (25,000 in the mouse) that almost exclusively express a single odorant receptor gene project to one glomerulus. This glomerulus only synapses with a few (25 in the mouse) mitral cells. This convergence allows for amplification of olfactory receptor neuron signals.

What are ocular dominance columns?

Ocular dominance columns are axons from the lateral geniculate nucleus that terminate in cortical layer 4 and are segregated by left eye and right eye signaling.

What is the function of the outer hair cells?

Outer cells are important in modulating basilar membrane motion, and studies indicate that they are a component of the cochlear amplifier.

How do the saccule and utricle detect different directions of head tilts and translational motion?

They detect different directional movement because the saccules are oriented vertically, while the utricles are oriented horizontally. Additionally, hair cell populations are divided in two by the striola within each saccule and utricle.

Which embryonic germ layer gives rise to the neural tube? Describe the process of neurulation. What does the neural tube become?

The neural tube arises from the ectoderm. During neurulation, the notochord sends signals to the ectoderm layer, causing cells to differentiate into neuroectodermal precursor cells, and this region of ectoderm thickens into the neural plate, which eventually folds into the neural tube. The neural stem cells of the neural tube become the central nervous system and most of the peripheral nervous system.

Is the retina part of the central nervous system? Explain.

The retina is part of the central nervous system because it is formed via outpocketing of the diencephalon during development. The retina contains a complex neuronal circuitry, allowing it to convert the graded electrical activity of the photoreceptors into action potentials that travel along the axons of the optic nerve.

If the right visual cortex stops functioning, what part of the visual field will be lost?

The right visual cortex receives input from the left visual field, thus the left visual field will be lost.

Explain how the semicircular canals are specialized to assess rotational acceleration of the head, whereas the otolith organs are specialized to detect linear acceleration and static position of the head relative to the gravitational axis.

The semicircular canals lay in different planes within each side of the head. The hair cells in the ampulla of each semicircular canal have only one orientation. Each semicircular canal works in concert with its partner, located on the other side of the head, with its hair cells oppositely aligned. When the head rotates, the cupula within the semicircular canal in the plane of rotation increase firing rate on one side and decrease firing rate on the other side. This partnership results in information about head rotation in any direction. The striola in the otolith organs creates an axis of symmetry within each organ. Thus, firing will increase on one side of the organ while it decreases in the other. The utricle and saccule are oriented in different planes to allow the head detect head tilts and translational movements in different directions.

On its way to the retina, light passes through tissues and fluids in which order? a. Cornea, aqueous humor, lens, vitreous humor, retina b. Sclera, aqueous humor, pupil, lens, vitreous humor, retina c. Cornea, vitreous humor, lens, aqueous humor, retina d. Sclera, vitreous humor, lens, aqueous humor, retina e. Cornea, aqueous humor, pupil, vitreous humor, retina

a. Cornea, aqueous humor, lens, vitreous humor, retina

A patient sustains a head injury resulting in damage of some glomeruli. Which effect would most likely result from this damage? a. Inability to detect certain smells b. Decreased sensitivity to smells but all smells would be detectable c. Proliferation of periglomerular cells d. Inability to detect all smells e. No effect; glomeruli would regenerate from stem cells

a. Inability to detect certain smells

An object located in the superior, temporal quadrant of the visual field would be mapped on which quadrant of the retina? a. Inferior, nasal b. Inferior, temporal c. Superior, nasal d. Superior, temporal e. Nasal, temporal

a. Inferior, nasal

. How would the firing of an ON-center ganglion cell respond as a light moved from the edge of the receptor field to the center of the receptive field? a. It would increase. b. It would decrease. c. It would increase then decrease. d. It would decrease then increase. e. There would be no change.

a. It would increase.

Which feature is responsible for the superior acuity of the fovea? a. Lack of retinal blood vessels b. Higher density of ganglion cells c. Increased concentration of rods d. Presence of the inner nuclear layer e. Maximum photon scattering before reaching the photoreceptors

a. Lack of retinal blood vessels

Why does neurite regrowth in the central nervous system often fail? a. Local overgrowth of glial cells b. Macrophage infiltration degenerates the cell body c. Absence of neurotrophic factor receptors on the axon d. Absence of oligodendrocyte precursor cells e. Inhibition of inflammatory response

a. Local overgrowth of glial cells

What is the most direct path that light information travels on its way to the optic nerve? a. Photoreceptor cell; bipolar cell; ganglion cell; optic nerve b. Photoreceptor cell; ganglion cell; bipolar cell; optic nerve c. Bipolar cell; photoreceptor cell; ganglion cell; optic nerve d. Bipolar cell; ganglion cell; photoreceptor cell; optic nerve e. Ganglion cell; photoreceptor cell; bipolar cell; optic nerve

a. Photoreceptor cell; bipolar cell; ganglion cell; optic nerve

Which evidence best supports the idea that the critical period for the organization of the visual cortex lasts a finite time? a. Monocular deprivation in a kitten leads to the majority of cortical cells responding to only the open eye. b. Monocular deprivation in an adult cat has little effect on the distribution of cortical neurons activated by stimulation of both eyes. c. A normal adult cat will have the majority of cortical cells activated by some degree to stimulation in both eyes. d. Monocular deprivation in a kitten leads to the majority of cortical cells responding to only the closed eye. e. Dark exposure after monocular deprivation will increase visual acuity in the previously closed eye.

b. Monocular deprivation in an adult cat has little effect on the distribution of cortical neurons activated by stimulation of both eyes.

A radioactive tracer is injected into the eye. Which tissue does this autoradiograph show? a. Retinal waves of Layers 2 and 3 b. Ocular dominance columns of Layer 4 c. Integrated retinal inputs of Layer 5 d. Binocular cells of Layers 2 and 3 e. White and gray matter of Layer 4

b. Ocular dominance columns of Layer 4

Which inductive signal has its effects on neural development by acting directly as a transcription factor? a. Fibroblast growth factor b. Retinoic acid bound to a retinoid receptor c. Wnt bound to receptor tyrosine kinase d. Bone morphogenetic protein e. Sonic hedgehog bound to Patched protein

b. Retinoic acid bound to a retinoid receptor

Which of the following correctly matches rods and cones with their properties? a. Rods: high spatial resolution; cones: color vision b. Rods: high sensitivity to light; cones: high spatial resolution c. Rods: color vision; cones: low spatial resolution d. Rods: high sensitivity to light; cones: low spatial resolution e. Rods: low sensitivity to light; cones: color vision

b. Rods: high sensitivity to light; cones: high spatial resolution

A decrease in extracellular H+ would decrease the ability to detect which taste? a. Sweet b. Sour c. Bitter d. Salty e. Umami

b. Sour

Why is the flexibility of the round window vital for proper functioning of the cochlea? a. It is responsible for the differing flexibility of the basilar membrane. b. There must be a space for liquid to move after displacement from the oval window because liquid does not compress. c. It gives rise to the topographical mapping of frequency in the cochlea, which allows for the decomposition of sound. d. The traveling wave in the fluid produces a shearing motion of the hair cells, which causes a voltage change in the round window. e. It allows for a traveling wave to reach a point of maximum displacement based on its

b. There must be a space for liquid to move after displacement from the oval window because liquid does not compress.

What is the major anatomical difference between ON-center and OFF-center bipolar cells that explains their selective response to light increments? a. They release different neurotransmitters onto ganglion cells. b. They have different glutamate receptor types. c. OFF-center cells have larger dendritic fields. d. They have different GABA receptor types. e. ON-center cells have larger cell bodies.

b. They have different glutamate receptor types.

Why is it important that transduction channels are open at rest? a. To maintain separation of perilymph and endolymph b. To allow hair cells to signal both increases and decreases c. To permit movement of stereocilia in either direction d. So that transmitter is released only when stereocilia move toward the kinocilium e. To facilitate vestibular nerve firing in only when the head changes position

b. To allow hair cells to signal both increases and decreases

What type of movement do the saccule and utricle respond to, respectively? a. Vertical; rotational b. Vertical; horizontal c. Rotational; vertical d. Horizontal; vertical e. Horizontal; rotational

b. Vertical; horizontal

How would an OFF-center neuron's firing rate change when a light was turned on, turned off, and then turned on again? a. Increase, increase, decrease b. Increase, decrease, increase c. Decrease, increase, decrease d. Decrease, increase, increase e. Decrease, decrease, increase

c. Decrease, increase, decrease

Which statement about the optic disc is false? a. It is a region without photoreceptors. b. It is where retinal nerves leave the eye to reach targets in the thalamus and midbrain. c. It contains a small depression known as the fovea. d. It can be an indicator for intracranial pressure. e. It creates a blind spot.

c. It contains a small depression known as the fovea.

Which repair mechanism does not occur in mammals when nervous tissue is damaged? a. Long-range regrowth of damaged axons in the peripheral nervous system b. Restoration of damaged central neurons c. Long-range regrowth of damaged axons in the central nervous system d. Neurogenesis e. Neuronal sprouting

c. Long-range regrowth of damaged axons in the central nervous system

A young patient is diagnosed with medulloblastoma. Which mechanism may be responsible for this cancer? a. Retinoic acid deficiency during gestation b. Upregulation of Notch protein c. Mutation in the Patched protein, part of the Sonic Hedgehog signaling pathway d. Folic acid deficiency during gestation e. Mutation in Hox genes

c. Mutation in the Patched protein, part of the Sonic Hedgehog signaling pathway

Which property best differentiates the types of cones? a. Their location in the retina b. The number of synapses on bipolar cells c. The photopigments they contain d. Their overall ratio to other types of cones e. Their shape and processes

c. The photopigments they contain

If a person tilted their head downward to tie their shoes and then straightened their head up again, firing rate of the vestibular nerve would a. increase and remain increased while the person was tying their shoes. b. increase only during the initial downward tilt of the head. c. decrease and remain decreased while the person was tying their shoes. d. decrease only during the initial downward tilt of the head. e. decrease during the initial downward tilt of the head and then increase as the head straightened back up.

c. decrease and remain decreased while the person was tying their shoes.

The mucus layer and the epithelium, with neural and supporting cells is(are) called a. Bowman's glands. b. basal cells. c. nasal mucosa. d. sustentacular. e. olfactory receptor neurons.

c. nasal mucosa.

In the inner ear, evidence suggests that the _______ is(are) an essential component of the cochlear amplifier. a. tectorial membrane b. stria vascularis c. outer hair cells d. endolymph e. scala media

c. outer hair cells

Which frequency would be detected by a 23-year-old female with normal hearing, but not be heard by a 72-year-old man with normal hearing? a. 10 Hz b. 300 Hz c. 5 kHz d. 20 kHz e. 40 kHz

d. 20 kHz

Applying a drug that increases cGMP levels in photoreceptors would cause which effect on a photoreceptor's response to a photon of light? a. An intensified depolarization from normal b. An attenuated depolarization from normal c. An intensified hyperpolarization from normal d. An attenuated hyperpolarization from normal e. There would be no effect

d. An attenuated hyperpolarization from normal

Which structure separates the olfactory epithelium from the olfactory bulbs? a. Olfactory tract b. Odorants c. Pyriform cortex d. Cribiform plate e. Sphenoid bone

d. Cribiform plate

Which type of movement would the saccule detect? a. Tilting of the head to the side b. Quick acceleration in a roller coaster c. Abrupt stop while walking d. Head tilt up toward the sky e. Spinning motion of a carnival ride

d. Head tilt up toward the sky

If a monkey is presented with an image of a train, neurons specific for which orientation would fire vigorously in V1? a. Left to right diagonal b. Right to left diagonal c. Vertical d. Horizontal e. Parallel

d. Horizontal

Like many of our other senses, vestibular percepts integrate additional sensory information. The loss of which sense would most affect perception? a. Taste b. Smell c. Hearing d. Vision e. Touch

d. Vision

A kitten is deprived of visual stimulation in one eye for the first 2 months of life. After the cat reaches adulthood, you record from different areas of the nervous system the response to direct electrical stimulation to the deprived eye. Where would you expect to see neuronal dysfunction compared to a control cat? a. Photoreceptor cells b. Retinal ganglion cells c. LGN cells d. Visual cortex cells e. All of the above

d. Visual cortex cells

What early evidence supported the idea that the peripheral nervous system could undergo repair? a. After optic nerve transection, Henry Head regained some visual acuity. b. Blocking macrophages in the region of nerve transection leads to increased recovery of function. c. After fibular nerve transection, mice provided with a leg splint recover motor function faster than those forced to exercise. d. To support growth of the eye, goldfish undergo neurogenesis in the retina. e. After radial nerve transection, Henry Head regained some sensation in his arm.

e. After radial nerve transection, Henry Head regained some sensation in his arm.

Which statement regarding critical periods is true? a. The behavior will not develop without input from the environment. b. Stimulation from the environment activates sensory or motor pathways. c. Stimulation from the environment leads to changes in synaptic connections. d. Neural connections are mostly permanent outside of the critical period timeframe. e. All of the above

e. All of the above

Which statement about rod and cone convergence in the retina is true? a. Many cones converge onto one cone bipolar cell. b. Convergence makes the cone system a better detector of light. c. Convergence increases the spatial resolution of rods. d. The one-to-one relationship of rods to bipolar and ganglion cells increases acuity. e. Convergence allows rods to pool signals, generating larger responses in bipolar cells.

e. Convergence allows rods to pool signals, generating larger responses in bipolar cells.

In which disease or disorder is olfaction dysfunction or anosmia part of the diagnostic criteria? a. Eating disorders only b. Schizophrenia only c. Parkinson's disease only d. Eating disorders and schizophrenia only e. Eating disorders, schizophrenia, Parkinson's disease, and Alzheimer's disease

e. Eating disorders, schizophrenia, Parkinson's disease, and Alzheimer's disease

An experimental animal develops with fetal abnormalities, specifically, the hemispheres of the forebrain do not have clear separation, and there are midline facial defects. Which condition does the experimental animal most likely have? a. Basal cell carcinoma b. Spina bifida c. Anencephaly d. Waardenburg's syndrome e. Holoprosencephaly

e. Holoprosencephaly

A photoreceptor cell is exposed to a flash of light. How does the membrane potential of this cell and its corresponding ON-center bipolar and ganglion cells change? a. Hyperpolarize, hyperpolarize, depolarize b. Depolarize, hyperpolarize, depolarize c. Hyperpolarize, depolarize, hyperpolarize d. Depolarize, hyperpolarize, hyperpolarize e. Hyperpolarize, depolarize, depolarize

e. Hyperpolarize, depolarize, depolarize

The lateral superior olive uses which of the following properties of interaural sound for localization? a. Time b. Frequency c. Waveform d. Period e. Intensity

e. Intensity

How does ionic composition of endolymph differ from most extracellular fluids? a. It is K+-poor and Na+-rich. b. It is Ca2+-poor and Na+-rich. c. It is K+-rich and Na+-rich. d. It is Ca2+-poor and Na+-poor. e. It is K+-rich and Na+-poor.

e. It is K+-rich and Na+-poor.

What type of neuronal repair is the most successful, clinically? a. Regrowth of damaged CNS neurons b. Neurogenesis c. Drug-induced neuronal migration d. Neuronal repair does not occur e. Peripheral nerve regeneration

e. Peripheral nerve regeneration

Which conclusion can be drawn regarding the high number of olfactory pseudogenes in humans? a. The number of odorants in the environment has decreased over evolutionary time. b. Human olfaction detects as many odorants as other mammals but requires fewer expressed genes. c. The number of odorant receptor genes is irrelevant for determining an organism's olfaction ability. d. Olfaction ability in humans is increasing, and we will soon be able to detect more odors than other mammals can. e. Reliance on olfaction has decreased throughout human evolution.

e. Reliance on olfaction has decreased throughout human evolution.

Which is an essential characteristic of neural stem cells? a. The ability to differentiate into any type of cell b. The ability to dispense with bacteria, damaged neuron, or toxic proteins in the brain c. The ability to guide neurons to their final location d. The ability to suppress the activity of the immune system e. The ability to differentiate into any cell type found in the central nervous system

e. The ability to differentiate into any cell type found in the central nervous system

After stereocilia move toward the kinocilium, a. mechanically-gated channels close. b. the hair cell hyperpolarizes. c. there is an efflux of calcium. d. there is a decreased release of transmitter from the hair cell. e. there is increased signaling in the vestibular nerve.

e. there is increased signaling in the vestibular nerve.