Brain disorders of aging
As we age, the brain becomes more vulnerable to certain disorders that can affect memory, thinking, and behavior. In this lesson, we'll cover a few examples of these.
1) Watch these videos:
2) Then, read these articles:
Know Your Brain - Alzheimer's disease
Know Your Brain - Parkinson's disease
3) Finally, answer these questions to test your understanding:
1. In Alzheimer's disease, a protein called tau is found in a misfolded state in clusters called:
- A. amyloid plaques
- B. Lewy bodies
- C. neurofibrillary tangles
- D. Pick bodies
Show Answer
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.
2. Acetylcholinesterase inhibitors (AChEIs) are a common treatment aimed at improving cognitive symptoms in Alzheimer's disease. How do they affect acetylcholine levels in the brain?
- A. they increase acetylcholine levels
- B. they decrease acetylcholine levels
- C. they do not affect acetylcholine levels; they only inhibit acetylcholinesterase
Show Answer
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.
3. Neuronal death in Parkinson's disease is typically most prominent in which of the following areas?
- A. cerebellum
- B. amygdala
- C. prefrontal cortex
- D. substantia nigra
Show Answer
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.
4. Parkinson's disease involves the death of dopamine-producing neurons. This neuronal death leaves patients dopamine deficient, which results in the characteristic movement-related symptoms Parkinson's patients display. If Parkinson's patients are dopamine deficient, why can't we just administer dopamine to them?
- A. dopamine is not available to administer as a drug
- B. if dopamine is administered, it will not make it to the brain
- C. if dopamine is administered, too much will enter the brain, causing side effects
- D. dopamine in drug form is too readily abused
Show Answer
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.
5. Which of the following is a subtype of frontotemporal dementia (FTD)?
- A. Lewy body dementia
- B. posterior cortical atrophy
- C. vascular dementia
- D. nonfluent variant primary progressive aphasia
Show Answer
Correct answer: D
Frontotemporal dementia, or FTD, is a term used to describe a collection of related brain disorders that involve the neurodegeneration of the frontal and temporal lobes. The three main subtypes of FTD are: behavioral variant FTD, semantic variant primary progressive aphasia, and nonfluent variant primary progressive aphasia.
