All Questions: 331-360
331. The most commonly used method in functional MRI (fMRI) for detecting brain activity is based on which signal?
- A. EEG (electroencephalographic) signal
- B. BOLD (blood-oxygen-level–dependent) signal
- C. DTI (diffusion tensor imaging) signal
- D. MEG (magnetoencephalographic) signal
Show Answer
Correct answer: B
Functional MRI (fMRI) typically uses the BOLD signal, which detects small changes in blood oxygenation associated with neural activity. Increased neural activity leads to increased local blood flow, changing the ratio of oxygenated to deoxygenated hemoglobin (and thus the fMRI signal intensity).
332. The dopamine neurons that travel in the mesolimbic dopamine pathway (a major pathway in the reward system) mostly originate in which structure?
- A. nucleus accumbens
- B. amygdala
- C. hippocampus
- D. ventral tegmental area (VTA)
Show Answer
Correct answer: D
Most dopamine neurons in the mesolimbic pathway originate in the ventral tegmental area (VTA) of the midbrain. These neurons project to the nucleus accumbens and other regions, playing a central role in reward, motivation, and reinforcement learning.
333. Alan Hodgkin and Andrew Huxley's experiments on the giant axons of this animal helped us to understand how neurons generate and transmit action potentials:
- A. elephant
- B. whale
- C. squid
- D. giraffe
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Correct answer: C
Hodgkin and Huxley performed their experiments on the giant axon of the squid. This axon is unusually large, which made it easier to insert electrodes and measure electrical changes, allowing them to uncover how action potentials are generated and transmitted.
334. These neurons have a cell body that gives rise to one axon and one dendritic structure. They are important in sensory systems, such as the visual system.
- A. unipolar neurons
- B. bipolar neurons
- C. multipolar neurons
- D. interneurons
Show Answer
Correct answer: B
Bipolar neurons are neurons with one axon and one dendritic structure extending from the cdell body. They relay sensory information in systems like the visual, olfactory, and auditory systems.
335. The majority of fibers in the optic tract project to the:
- A. superior colliculus
- B. lateral geniculate nucleus
- C. primary visual cortex
- D. medial geniculate nucleus
Show Answer
Correct answer: B
Most axons in the optic tract terminate in the lateral geniculate nucleus (LGN) of the thalamus. The LGN serves as the primary relay center for visual information, sending projections via the optic radiations to the primary visual cortex in the occipital lobe.
336. Multiple sclerosis, an immune-mediated disease that targets myelin, primarily affects the:
- A. central nervous system
- B. peripheral nervous system
- C. autonomic nervous system
- D. enteric nervous system
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Correct answer: A
Multiple sclerosis is a central nervous system disorder that is characterized by damage to myelin, the insulatory material that surrounds the axons of neurons. This damage is linked to disruptions in healthy neuronal function, which are thought to lead to the symptoms of the disease.
337. The spinal cord is made up of how many segments?
- A. 12
- B. 26
- C. 31
- D. 48
Show Answer
Correct answer: C
The spinal cord has 31 segments, each giving rise to a pair of spinal nerves. There are: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal segments.
338. This is the most common type of synapse in the human nervous system:
- A. axoaxonic
- B. dendrodendritic
- C. axosomatic
- D. axodendritic
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Correct answer: D
Synapses can form between many different parts of neurons, but those that form between the axon terminals of one neuron and the dendrites of another—known as axodendritic synapses—are by far the most common type of synapse in the human nervous system.
339. Which of the colliculi are primarily involved in auditory processing?
- A. superior
- B. inferior
- C. medial
- D. parietooccipital
Show Answer
Correct answer: B
The superior and inferior colliculi are found in the midbrain, on the posterior surface of the brainstem. The inferior colliculi are involved with auditory processing.
340. This blue-colored region is the main site of norepinephrine production for the brain:
- A. locus coeruleus
- B. ventral tegmental area
- C. raphe nucleus
- D. azure nucleus
Show Answer
Correct answer: A
Norepinephrine-producing neurons in the central nervous system are primarily concentrated in the pons and medulla. The most prominent of these groups of neurons is a nucleus called the locus coeruleus, which is the main site of norepinephrine production for the central nervous system.
341. After a large turkey meal, you begin to feel very drowsy. Which physiological mechanism below is most directly responsible for that post-meal sleepiness?
- A. increased brain uptake of tryptophan from the turkey
- B. activation of the sympathetic nervous system during digestion
- C. increased parasympathetic activity promoting "rest and digest" functions
- D. elevated GABA release triggered by high fat foods
Show Answer
Correct answer: C
Parasympathetic activation ramps up after a large meal to support digestion, increasing gut blood flow and promoting relaxation (and potentially drowsiness). While dietary tryptophan can contribute slightly to post-meal tiredness, turkey isn’t unusually high in tryptophan compared to other meats, and the drowsiness people feel after a turkey dinner is far more related to the overall size and carbohydrate load of the meal than to turkey itself.
342. The tiny bumps that cover the tongue, called [BLANK], contain taste buds, which in turn house taste receptor cells that interact with tastants in the mouth.
- A. taste follicles
- B. taste pores
- C. gustatory mounds
- D. papillae
Show Answer
Correct answer: D
The tongue is covered with many little bumps, which are sometimes mistakenly called taste buds. These small lumps of tissue are known as papillae. Taste buds are found in the walls of papillae and the grooves surrounding them, and each taste bud contains anywhere from 50 to 150 taste receptor cells.
343. Which amino acid is modified to synthesize dopamine in the brain?
- A. glutamine
- B. tryptophan
- C. tyrosine
- D. histidine
Show Answer
Correct answer: C
Dopamine is synthesized from the amino acid tyrosine, which is first converted into L-DOPA by tyrosine hydroxylase, and then decarboxylated into dopamine by DOPA decarboxylase.
344. The axons of olfactory receptor neurons in the olfactory epithelium project directly to which brain structure?
- A. hippocampus
- B. olfactory bulb
- C. thalamus
- D. amygdala
Show Answer
Correct answer: B
The axons of olfactory receptor neurons in the olfactory epithelium synapse in the olfactory bulb, which is the first relay in the brain for processing smell information. From there, signals are sent to higher brain areas, including the olfactory cortex and other limbic structures, for perception and emotional responses to odors.
345. After head trauma, a patient has damage to his right hypoglossal nerve. When he sticks out his tongue, which side is it likely to deviate toward?
- A. right
- B. left
- C. neither; it won't deviate at all
Show Answer
Correct answer: A
If the hypoglossal nerve on only one side is damaged and the patient is asked to protrude his or her tongue, the tongue will typically deviate toward the side of the damaged nerve.
346. The dorsal roots, which carry sensory information, enter the spinal cord at the:
- A. posterolateral sulcus
- B. ventral median fissure
- C. ventrolateral sulcus
- D. central canal
Show Answer
Correct answer: A
The dorsal roots enter the spinal cord at the posterolateral (aka dorsolateral) sulcus. They carry sensory information into the spinal cord.
347. Neurotransmitters are typically stored in and released from which part of a neuron?
- A. dendrites
- B. nucleus
- C. axon
- D. axon terminals
Show Answer
Correct answer: D
Neurotransmitters are typically stored in and released from the axon terminals (synaptic boutons) of the neuron.
348. This structure is the main component of the ventral striatum, and is thought to play an important role in reward processing:
- A. amygdala
- B. globus pallidus
- C. nucleus accumbens
- D. ventral tegmental area
Show Answer
Correct answer: C
The nucleus accumbens is the major component of the ventral striatum, and is best known for its role in reward processing.
349. The hippocampus is often subdivided anatomically into 4 regions, designated CA1 through CA4. What does the CA stand for?
- A. cellular array
- B. cortical area
- C. central arch
- D. cornu ammonis
Show Answer
Correct answer: D
The structure of the hippocampus has been likened to the curved horn of a ram or the horns of the ancient Egyptian god Ammon and thus has been called Ammon’s horn or cornu ammonis. Accordingly, the hippocampus has been subdivided anatomically into 4 regions designated CA1 through CA4; the CA stands for cornu ammonis.
350. Which part of the cerebellum is MOST responsible for comparing actual limb position with the intended position during a movement?
- A. vestibulocerebellum
- B. spinocerebellum
- C. cerebrocerebellum
- D. dentate nucleus
Show Answer
Correct answer: B
The spinocerebellum receives information about limb position from the spinal cord and uses this information, for example, to compare where a limb is in space with where it should be if the movement were going as planned. If there is a discrepancy, the spinocerebellum can modify motor signals to correct any errors in the movement.
351. Why is the primary visual cortex sometimes referred to as the "striate cortex?"
- A. its neurons fire in a striped pattern when exposed to visual stimuli
- B. myelinated axons runs along calcarine sulcus, creating a striped appearance
- C. it receives input from the retina in the form of stripe-like wave patterns
- D. the optic tract forms a stripe as it enters the cortex
Show Answer
Correct answer: B
The primary visual cortex is found in the occipital lobe, surrounding and extending into a sulcus called the calcarine sulcus. A large band of myelinated axons runs along the edges of the calcarine sulcus, giving the primary visual cortex a striped appearance. Because of this, it is sometimes called the striate cortex.
352. During neural development, these glial cells act as scaffolding that new neurons use to travel from their site of origin to their final destination in the brain:
- A. radial glia
- B. oligodendrocytes
- C. astrocytes
- D. satellite cells
Show Answer
Correct answer: A
Radial glia are involved in neurogenesis and neural development. They generate new neurons and also provide a scaffold that newborn neurons use to travel from their site of origin to their final destination in the brain.
353. Most of the cerebral cortex in humans is organized into ____ layers, which are distinguished from one another by differences in cell type and cell density.
- A. 2
- B. 4
- C. 5
- D. 6
Show Answer
Correct answer: D
Most of the cerebral cortex in humans is classified as neocortex, which is so named because it is thought to have appeared relatively recently in vertebrate evolution. Neurons in the neocortex are typically arranged in six layers, which are distinguished from one another by differences in cell type and cell density.
354. Which of the following best describes what happens during phototransduction in a rod cell when it is exposed to light?
- A. sodium channels open, causing depolarization and increased glutamate release
- B. sodium channels close, causing hyperpolarization and decreased glutamate release
- C. potassium channels close, causing depolarization and increased glutamate release
- D. calcium channels open, causing hyperpolarization and decreased glutamate release
Show Answer
Correct answer: B
Phototransduction works in a counterintuitive way compared to most neural signaling, where stimulation opens channels, depolarizes the cell, and increases neurotransmitter release. In photoreceptors, light lowers cGMP levels, which closes sodium channels. This hyperpolarizes the cell and reduces glutamate release. That drop in glutamate is the signal that light is present.
355. This is the largest and most complex division of the autonomic nervous system:
- A. enteric nervous system
- B. sympathetic nervous system
- C. parasympathetic nervous system
- D. somatic nervous system
Show Answer
Correct answer: A
The enteric nervous system is involved with the regulation of the gastrointestinal tract. It consists of networks of neurons found in the walls of the GI tract and other digestive organs, and it’s thought to contain somewhere between 400-600 million neurons, which would make it the largest and most complex division of the autonomic nervous system.
356. This positively-charged ion flows out of the neuron during the falling phase of an action potential, promoting repolarization of the cell:
- A. sodium
- B. magnesium
- C. potassium
- D. calcium
Show Answer
Correct answer: C
Potassium (K⁺) ions flow out of the neuron during the falling (repolarization) phase of the action potential. This outward movement of positive charge helps restore the membrane potential toward its resting state after depolarization.
357. If a sample of cerebrospinal fluid is needed, from which region of the spinal cord is it typically obtained from?
- A. cervical
- B. thoracic
- C. lumbar
- D. sacral
Show Answer
Correct answer: C
A sample of cerebrospinal fluid (CSF) is typically obtained from the lumbar region of the spine, below the end of the spinal cord (usually between L3–L4 or L4–L5). This area contains the lumbar cistern, which is filled with CSF but below the end of the spinal cord, making it a safe location to insert a needle without risking injury to the spinal cord.
358. During neural development, which glial cells provide scaffolding that allows newly formed neurons to migrate from their origin to their final destination?
- A. oligodendrocytes
- B. satellite cells
- C. astrocytes
- D. radial glia
Show Answer
Correct answer: D
Radial glia are neural stem cells that play a key role in neurogenesis and brain development. They generate neurons and provide a scaffold that guides migrating neurons from their origin to their final position in the brain.
359. When referring to brain structures above the brainstem, the term "dorsal" indicates:
- A. toward the front of the brain
- B. toward the back of the brain
- C. toward the top of the brain
- D. toward the bottom of the brain
Show Answer
Correct answer: C
When we are looking at the spinal cord, dorsal refers to the back and ventral refers to the region nearest the abdomen. Above the level of the brainstem, however, dorsal refers to the superior portion of the brain and ventral refers to the inferior portion.
360. The glymphatic system plays an important role in clearing metabolic waste from the brain. How is cerebrospinal fluid (CSF) flow through the glymphatic system thought to change during sleep compared to wakefulness?
- A. it increases during sleep
- B. it remains unchanged during sleep
- C. it decreases during sleep
- D. it stops completely during sleep
Show Answer
Correct answer: A
Evidence suggests that the glymphatic system becomes more active during sleep, allowing cerebrospinal fluid (CSF) to flow more freely through perivascular channels. This enhanced flow facilitates the clearance of metabolic waste products, such as amyloid-beta and tau, from the brain.
