All Questions: 31-60

Correct answer: A

Neurotransmitter reuptake is a method neurons use to remove excess neurotransmitter molecules from the synaptic cleft. If you were to inhibit reuptake, it would typically cause more neurotransmitter molecules to accumulate in the synaptic cleft (because the neuron would be less capable of removing them). Inhibition of reuptake is the mechanism for a number of psychoactive drugs, including recreational drugs (e.g., cocaine) and therapeutic drugs (e.g., SSRIs).

Correct answer: B

The word "cerebellum" comes from Latin, and it translates to "little brain." By some estimates, the cerebellum contains up to 80% of the brain's neurons. Part of the reason for this high number of neurons is that the cerebellar cortex is densely packed with very small neurons called granule cells.

Correct answer: B

Although phrenology was controversial in its day, and now is considered pseudoscience, Gall was actually a highly-trained and very knowledgeable neuroanatomist and physician who made a number of important contributions to neuroanatomy. Even though his ideas about skull shape and personality were misguided, his hypothesis that certain functions are localized to specific areas of the cortex helped to shape ideas about the localization of brain function that became prominent in the 20th century.

Correct answer: B

The medulla (a region of the brainstem) is involved in a long list of functions, but perhaps the most important among them is the regulation of vital functions. The medulla receives information from receptors in the body about heart rate, blood pressure, and oxygen levels in the blood (among other things). If any of these levels are outside of a desire range, the medulla can adjust cardiac and respiratory function to attempt to return them to where they should be.

Correct answer: C

Hair cells get their name because they have small hair-like projections called stereocilia. The stereocilia deflect in response to mechanical forces, with the result being the production of electrochemical signals used to convey sensory information. Hair cells in the cochlea are responsible for creating signals to transmit information about sound waves, while those in the vestibular system are responsible for creating signals to transmit information about head movement.

Correct answer: A

Rods are sensitive to low levels of illumination, but cones do not function effectively at low light levels. In typical moonlight levels of illumination, rods would be the primary source of information for vision. Since rods don't allow for color perception, we typically see in grayscale in low levels of illumination. Often, we may believe we perceive color at these low light levels, but it is caused by our brain "applying" color based on the expected color due to previous experience.

Correct answer: C

A sulcus (pl. sulci) is a term used in anatomy to refer to a fissure or groove. In neuroanatomy, the term is used to describe the many fissures riddling the surface of the cerebral cortex. It is also used to describe fissures in other nervous system structures, such as the cerebellum and spinal cord. Gyrus (pl. gyri) is a term used to describe the ridges of the cerebral cortex.

Correct answer: A

Most addictive drugs cause dopamine levels to increase, especially in areas of the brain that are considered part of the brain's reward system (e.g,. nucleus accumbens). While this relationship might seem to imply that dopamine causes pleasure, evidence suggests a more nuanced role for dopamine in addiction.

Correct answer: C

The hypoglossal nerve (cranial nerve XII) controls most of the muscles of the tongue. When there is damage to the hypoglossal nerve or nucleus on one side, it can cause tongue weakness and atrophy of muscles on the side of the damaged nerve/nucleus. When the patient sticks out their tongue, it will typically deviate toward the side of the damage.

Correct answer: B

Even though the brain is where we process (and become aware of) pain in the body, there are no pain receptors in brain tissue itself. This explains how brain surgery can be performed on awake patients---a procedure known as "awake craniotomy"---without them feeling pain from manipulation of their brain tissue. While brain tissue doesn't have pain receptors, however, there are structures in the cranium that are pain-sensitive, such as the meninges (particularly the dura mater).

Correct answer: C

Locus coeruleus means "blue spot" in Latin, and it's so named because it has a bluish tinge in unstained brain tissue. It is the primary site of norepinephrine production in the brain, and it sends norepinephrine throughout the cerebral cortex as well as to a variety of other structures including the amygdala, hippocampus, cerebellum, and spinal cord.

Correct answer: B

Patients with Wernicke's aphasia have no trouble producing fluent speech, but their speech often has little meaning. They might substitute one word for another, mix up the sounds within words, or even create new words altogether—in both spoken and written language. Their ability to comprehend language is also impaired.

Correct answer: B

The internal carotid arteries travel up the side of the neck and to the brain, supplying the brain with around 70-80% of its blood. The vertebral arteries supply the other 20-30%.

Correct answer: A

The dorsal roots enter the posterior side of the spinal cord, carrying sensory information to the spinal cord. The ventral roots leave the anterior side of the spinal cord, carrying motor signals to cause movements.

Correct answer: D

Almost all drugs used to treat schizophrenia have the blockade of activity at dopamine receptors as a key part of their mechanism. This common action has been used as evidence to support the idea that dopamine levels in certain parts of the brain may be too high in schizophrenia. Although evidence does suggest increased dopamine activity plays a role in schizophrenic symptoms, research also suggests dopamine irregularities don't explain all of the symptoms of schizophrenia.

Correct answer: C

The doctor was testing the patient's pupillary light reflex. In a healthy reflex, when a light is shone into one eye, both pupils constrict. If the light is shone into one eye and neither pupil restricts, it suggests a deficit with the sensory portion of the reflex: the optic nerve. In other words, the reflex doesn't occur because the light is not detected. If light is shone into one eye and only one pupil constricts, it suggests damage to the oculomotor nerve on the side lacking a response.

Correct answer: B

The genetic mutations that commonly lead to color blindness are frequently found on the X chromosome. Because females have two X chromosomes, if there is a mutation on an X chromosome gene in a female, it is more likely to be balanced out by a "healthy" gene on the other X chromosome. In males, however, a mutation on an X chromosome gene is more likely to have an influence due to a lack of another X chromosome and thus a lack of a "healthy" gene to counteract the mutation.

Correct answer: C

The hormonal stress response of the HPA axis first involves secretion of corticotropin-releasing hormone from the hypothalamus. CRH causes the secretion of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland. ACTH travels to the adrenal glands, and prompts the secretion of cortisol.

Correct answer: A

Multiple studies have found that depressed patients tend to have smaller hippocampi than non-depressed individuals. It's important to note that it's unclear whether this reduced hippocampal volume is a cause or consequence of depression, and the reduction in hippocampal volume can vary substantially among individuals with depression. Overall, the neurobiology of depression is still poorly understood.

Correct answer: C

In multiple sclerosis (MS), a patient's immune system seems to target myelin as a foreign substance and attacks it. This attack and the associated inflammatory response leads to damage to myelin (and axons), which disrupts the conduction of action potentials and is thought to cause many of the symptoms of the disease.

Correct answer: C

The meninges are a group of membranes that surround the brain and spinal cord, providing protection and support as well as serving a number of other purposes. The outermost and thickest layer of the meninges is the dura mater. It is a tough and fibrous layer that helps protect the brain.

Correct answer: D

The diencephalon is found above the brainstem at the center of the brain and includes the thalamus, hypothalamus, subthalamus, and epithalamus (which consists primarily of the pineal gland and the habenulae).

Correct answer: A

Neurotransmitters are typically released FROM the presynaptic membrane and INTO the synaptic cleft. They typically bind to receptors on the postsynaptic membrane. Gap junctions (the last answer choice) are regions where neurons communicate at electrical synapses (which don't involve neurotransmitters).

Correct answer: B

The doctor is testing a reflex called the corneal reflex. In a healthy reflex, when one cornea is touched, both eyes blink at the same time. If one cornea is touched and neither eye blinks, it suggests a deficit with detecting the sensation. The trigeminal nerve is the main sensory nerve for the head, and would be responsible for detecting this sensation; thus, the deficit here would likely be with the right trigeminal nerve. The facial nerve is responsible for the motor portion of the reflex.

Correct answer: C

The blood-brain barrier is a complex that surrounds most of the blood vessels in the brain. It acts as a barrier between the bloodstream and the extracellular space of the brain, allowing only certain substances like water, oxygen, and small lipid-soluble substances to easily cross from the blood into the brain.

Correct answer: A

The visual cortex takes up much of the occipital lobe; it includes the primary visual cortex and the surrounding visual association areas. While a stroke can cause a variety of symptoms, if damage were confined to the occipital lobe, one would expect a visual deficit to be prominent.

Correct answer: C

Cotard's syndrome is a rare condition where patients believe they are dead or in some other state that doesn't align with typical existence (e.g., lacking blood or internal organs, existing in a state of eternal oblivion). The condition is named after neurologist Jules Cotard, who in the late 19th century was the first to realize that this phenomenon was a clinically significant pattern of symptoms that represented a disorder.

Correct answer: B

The dorsal columns-medial lemniscus pathway is the main pathway that carries tactile sensations---including sensations of touch, pressure, and vibration---to the brain. It also carries information about proprioception. Neurons in the dorsal columns travel up the spinal cord and synapse in the brainstem on neurons that form the second part of the pathway: the medial lemniscus. This travels up to the somatosensory cortex, which is the main cortical area for processing touch sensations.

Correct answer: C

The unmyelinated gaps in a myelin sheath are called nodes of Ranvier, named after their discoverer: Louis-Antoine Ranvier. The nodes of Ranvier are rich in sodium channels, which open in response to an action potential traveling down an axon, allowing positive sodium ions to rush in and "recharge" the action potential as it moves along the axon.

Correct answer: D

The ventral tegmental area, or VTA, is in the brainstem. Although it contains several different types of neurons, it is primarily characterized by its dopaminergic neurons, which project from the VTA throughout the brain, including to reward-related areas like the nucleus accumbens.