All Questions: 541-570

Correct answer: B

The hypothalamic-pituitary-adrenal, or HPA, axis is best known for its role in our body’s reaction to stress. The HPA axis includes a group of hormone-secreting glands from the nervous and endocrine systems: the hypothalamus, pituitary gland, and adrenal glands.

Correct answer: C

The anterior horn contains the cell bodies of motor neurons that activate skeletal muscle. These neurons, called alpha motor neurons, leave the cord in the ventral roots and represent the way the nervous system enacts voluntary and involuntary movements.

Correct answer: D

Ganglion cells carry the visual signal out of the eye. They leave the eye in a large cluster at an area called the optic disc. The optic disc doesn't contain any photoreceptors, and so represents an area on the retina that can't process visual information, creating a natural blind spot.

Correct answer: A

The term glia comes from a Greek word that means glue, and glial cells got this name b/c they were thought to simply hold neurons in place. We now know, however, that glia have many other functions.

Correct answer: C

There are several clusters of cholinergic neurons throughout the brain. Some are found in the basal forebrain; they include the medial septal nucleus, the nucleus of the diagonal band, and the nucleus basalis. Others are found in the brainstem, including the pedunculopontine nucleus and laterodorsal tegmental nucleus.

Correct answer: A

Computed tomography is a type of structural neuroimaging. It is usually called a CAT or CT scan. It involves taking a series of x-ray images from various locations around the head. These images can then be combined to construct an image of the brain.

Correct answer: A

Glutamate is removed from the synaptic cleft by a class of transporter proteins called the excitatory amino acid transporters, or EAATs.

Correct answer: B

According to the reward prediction error hypothesis, dopamine signals are strongest when we encounter something we find to be better than we expected it to be.

Correct answer: C

The superior cerebellar arteries supply the superior surface of the cerebellum.

Correct answer: A

Evidence on the effectiveness of melatonin supplementation is mixed but generally indicates that it produces modest benefits in promoting sleep. Meta-analyses suggest that melatonin can reduce the time it takes to fall asleep, slightly increase total sleep time, and improve sleep quality. It appears to be particularly effective for circadian rhythm disruptions, such as jet lag.

Correct answer: B

Global aphasia results from extensive damage to language areas in the dominant-hemisphere language network. It is linked to severe impairments in both speech production and language comprehension.

Correct answer: C

Narcolepsy is a chronic condition that causes excessive daytime sleepiness and leads to an increased tendency to fall asleep during daytime activities. The majority of people who suffer from narcolepsy also experience cataplexy, which involves brief, sudden episodes of muscle weakness or paralysis---often brought on by strong positive emotions.

Correct answer: D

Facial nerve damage can cause a variety of symptoms, but the most recognizable of them is weakness and/or paralysis of the muscles of facial expression on the same side of the head that the damaged nerve supplies.

Correct answer: A

The motor cortex is a region of cortex in the frontal lobe that is involved with voluntary movement. It is located anterior to a large sulcus called the central sulcus and is often divided into three regions: the primary motor cortex, premotor cortex, and supplementary motor cortex (the latter two make up the nonprimary motor cortex).

Correct answer: B

There are two known cannabinoid receptors, CB1 and CB2---both of which are g protein-coupled receptors. CB1 receptors are found throughout the nervous system, while CB2 receptors are primarily found on immune cells. It's thought that THC's main psychoactive effects are mediated through its action at CB1 receptors.

Correct answer: C

Norepinephrine is synthesized from dopamine in a reaction catalyzed by the enzyme dopamine beta-hydroxylase.

Correct answer: A

The primary visual cortex, also known as V1, is a brain region that is critically important for the processing of visual information. It is found in the occipital lobe, surrounding and extending into a sulcus called the calcarine sulcus.

Correct answer: B

Inside rod cells there is a light-sensitive pigment called rhodopsin, which consists of a protein called opsin and a light-absorbing molecule called retinal. When retinal absorbs a photon of light, it changes shape (from 11-cis-retinal to all-trans-retinal). This conformational change activates opsin, which then activates a G protein called transducin, initiating the process of visual transduction.

Correct answer: D

Deep brain stimulation is a neurosurgical approach that involves the use of brain-implanted electrodes to treat a variety of neurological and psychiatric conditions. In Parkinson's disease, an electrode is typically placed near structures like the subthalamic nucleus, whose overactivity in the disease is thought to contribute to movement problems like difficulty initiating movement.

Correct answer: C

Ion channels are proteins found in the cell membrane that allow charged particles called ions to move into or out of a cell. Ion channels are essential for normal function in excitable cells, and problems with ion channels can lead to a wide range of disorders, known as channelopathies.

Correct answer: B

The spinothalamic tract is the primary pathway for carrying pain and temperature information from the body to the brain.

Correct answer: C

Although several ions contribute to the resting membrane potential, potassium (K⁺) plays the greatest role because many potassium leak channels are open when a neuron is at rest. This makes the membrane much more permeable to potassium than to other positively charged ions, so the resting membrane potential is much closer to the equilibrium potential for potassium.

Correct answer: B

The spinal cord leaves the skull through an opening called the foramen magnum and travels down the vertebral column.

Correct answer: D

In REM sleep, EEG activity resembles what’s seen in stage 1 or restful waking. During REM sleep, the muscles are completely relaxed and limp but the eyes are moving rapidly. This is the time of sleep when our most vivid dreams are likely to occur.

Correct answer: A

The third ventricle is connected to the fourth ventricle by the cerebral aqueduct.

Correct answer: C

Tactile discrimination is carried by the dorsal columns–medial lemniscus (DCML) pathway, which crosses to the opposite side of the brainstem before reaching the cerebral cortex. As a result, damage to the right cerebral hemisphere can impair tactile discrimination on the left side of the body.

Correct answer: C

Cell bodies of postganglionic sympathetic neurons are found in the sympathetic ganglia, which are primarily located in the sympathetic chain and prevertebral ganglia.

Correct answer: B

The arachnoid mater is immediately below the dura mater. The arachnoid mater gets its name because it has the consistency and appearance of a cobweb. It is much less substantial than the dura. Strands of connective tissue called arachnoid trabeculae stretch between the arachnoid and pia mater.

Correct answer: B

The developing brain typically produces more neurons than it ultimately needs, and neurons that fail to establish appropriate connections or receive sufficient survival signals may undergo programmed cell death, also known as apoptosis.