Disorders Questions

Correct answer: D

Capgras syndrome is a rare condition where patients begin to believe that people close to them (e.g., spouse, parents, children) have been replaced by imposters who look and act just like their loved ones. The delusions can also extend to individuals who are not close to the patient, and over time Capgras patients often begin to identify an increasing number of imposters in their life.

Correct answer: D

Parkinson's disease (PD) is a neurodegenerative disease, meaning it is characterized by the degeneration and death of neurons. While neuronal death in PD can occur in various brain areas, the substantia nigra is most affected. The substantia nigra is a region in the brainstem that is rich in dopamine neurons; these neurons are thought to play important roles in facilitating movement. By the time a PD patient dies, they may have lost up to 70% of the dopamine neurons in their substantia nigrae.

Correct answer: B

Broca's aphasia is characterized by a deficit in the ability to produce language, but language comprehension is typically intact. Broca's aphasia was named for its association with damage to Broca's area, a region of the brain implicated in language production, but it can result from damage to other areas of the brain as well.

Correct answer: B

Dopamine is available in drug form, and is used in certain situations (e.g., low blood pressure) in medical settings. Dopamine, however, cannot cross the blood-brain barrier (BBB). Thus, if given to Parkinson's patients, it never makes it to the brain. This is why we often use L-DOPA to treat Parkinson's disease, as it can cross the BBB and the brain can use it to make more dopamine. Learn more here:

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: 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: 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

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: C

Spina bifida is a birth defect that involves disrupted formation of a structure called the neural tube. The neural tube forms in early neural development, and eventually will become the brain and spinal cord. In spina bifida, the neural tube either does not form or close properly.

Correct answer: A

One of the hallmark signs of Alzheimer's disease is the accumulation of misfolded amyloid beta protein in amyloid plaques outside of neurons. It's still uncertain, however, exactly what role these plaques play in the progression of the disease.

Correct answer: B

Narcolepsy is linked to a loss of orexin-producing neurons in the hypothalamus, leading to low orexin levels. Orexin neurons have an excitatory effect on several regions of the brain that are involved in promoting wakefulness and suppressing REM sleep. Thus, the loss of these neurons leads to deficiencies in maintaining wakefulness. The cause of the loss of orexin neurons in narcolepsy is not completely understood, but several lines of evidence implicate an autoimmune mechanism.

Correct answer: D

Amyotrophic lateral sclerosis (ALS) is a debilitating neurodegenerative disorder characterized by a progressive loss of motor function. ALS affects upper motor neurons and lower motor neurons. As these motor neurons stop working, muscles also begin to atrophy; this can eventually lead to respiratory failure, which is often the cause of death in ALS patients.

Correct answer: D

The white matter lesions are a hallmark sign of MS. The disease is characterized by damage to the myelin sheaths surrounding the axons of neurons in the central nervous system. This myelin damage disrupts the conduction of action potentials along these axons, which is thought to cause many of the symptoms of the disease. The damage is thought to be caused by an autoimmune attack.

Correct answer: A

The function of acetylcholinesterase is to remove acetylcholine from the synapse—in effect reducing the effect the neurotransmitter can have at that synapse. By inhibiting acetylcholinesterase activity, AChEIs cause acetylcholine levels to increase. In the process, these drugs can lead to modest improvements in memory.

Correct answer: D

The rupture of a brain aneurysm typically causes bleeding into the area surrounding the brain---a condition known as subarachnoid hemorrhage. Subarachnoid hemorrhage is an extremely dangerous situation with high rates of fatality.

Correct answer: D

Wernicke-Korsakoff syndrome typically involves a severely impaired ability to form new memories, disrupted recall of previously-formed memories, and a variety of other symptoms. It is caused by a thiamine deficiency, and is often (although not always) linked to alcoholism.

Correct answer: B

Huntington's disease can be traced back to a mutation in the huntingtin (HTT) gene. The mutation causes a high degree of trinucleotide repetition in the gene. The mutation is an autosomal dominant mutation, meaning that if it's inherited it will be expressed, and offspring have a 50% chance of inheriting the mutated gene if one parent has it.

Correct answer: A

Although mechanisms can vary slightly for different types of seizures, in general seizures are caused by excessive and synchronized electrical activity in the brain. In a typical seizure, large groups of neurons fire at the same time, leading to spikes in neural activity. During a seizure, this abnormal neural activity can spread due to the failure of inhibitory mechanisms, leading to widespread abnormalities in brain function.

Correct answer: C

The agent in prion diseases (also called transmissible spongiform encephalopathies) is thought to be a misfolded form of a protein called prion protein, or PrP. This misfolded form of the protein seems to be able to induce other proteins to become abnormally folded, and it has been shown to be able to transmit disease in certain situations.

Correct answer: D

Hemispatial neglect (aka contralateral neglect) typically emerges after a stroke that affects the right cerebral hemisphere, especially when the stroke impacts the parietal lobe. Patients with hemispatial neglect experience a deficit in attention to one side of the visual field (typically the side opposite the stroke damage).

Correct answer: C

Prosopagnosia, also sometimes referred to as "face blindness," involves a deficit in the ability to perceive or recognize faces. The severity of the disorder varies, with the most extreme cases being unable to perceive facial features at all and milder cases having a difficult time recognizing people based solely on facial features. It can come about after some sort of damage to the brain, but congenital cases also occur.

Correct answer: A

One supported hypothesis suggests that PTSD involves decreased activity in the medial prefrontal cortex and increased activity in subnuclei of the amygdala that are involved in the identification of threats.

Correct answer: A

Meningiomas are the most common primary brain tumor. (If a brain tumor begins in the brain, it’s called a primary brain tumor. If it spreads to the brain from some other location, it’s known as a secondary brain tumor.) Meningiomas form in the meninges, and are usually benign.

Correct answer: D

Broca's aphasia mostly involves deficits in producing language, and Wernicke's aphasia mostly involves deficits in language comprehension and the production of meaningful language. Global aphasia, however, involves a combination of symptoms from Broca's and Wernicke's aphasia. Patients with global aphasia experience deficits in both the production and comprehension of speech.

Correct answer: D

Seasonal affective disorder (SAD) is a subtype of depression or bipolar disorder in which symptoms appear at specific times of the year and go into full remission at other times. Several hypotheses have been proposed to explain seasonal affective disorder, with one being that low levels of vitamin D could play a role. The evidence is mixed, however, and suggests vitamin D probably only plays a role in certain cases.

Correct answer: A

Lyme disease is a tick-borne illness caused by a group of bacteria belonging to the genus Borrelia. When Lyme disease affects the nervous system, the resulting condition is called Lyme neuroborreliosis.

Correct answer: A

A lumbar puncture involves taking a sample of cerebrospinal fluid from around the spinal cord; it is the only definitive way to diagnose meningitis. Neuroimaging, a physical exam, and blood tests can all support the diagnosis or provide additional information on the infection.

Correct answer: C

Tau protein is normally found inside neurons and involved in maintaining neuronal structure. In Alzheimer's disease it accumulates inside neurons in clusters called neurofibrillary tangles.

Correct answer: B

In CTE, tau proteins accumulate in neurons and other cells like astrocytes to form abnormal clusters or aggregates. The tau aggregates are called neurofibrillary tangles when they form in neurons and astrocytic or glial tangles when they form in astrocytes. These protein aggregates are a primary hallmark of CTE.