Chapter 4

Question 1

Which areas of the brain are mostly affected in normal aging (without dementia)?

Answer 1

Cortical: Primarily frontal and temporal lobes as well as the amygala-hippocampal region. Posterior portion of the frontal cortex, because of the higher amount of white matter. Multimodal (tertiary) association areas (e.g. PFC) are more vulnerable than primary areas.

Subcortical: nucleus basalis of Mynert, dorsal raphe nuclei and locus coeruleus.

Question 2

In how far does the degeneration of the cholinergic system influence the neuronal vascularization?

Answer 2

Acetylcholine influences vasodilatation by acting on the nicotinic receptors. A cholinergic deficit reduces nicotinic receptor activity and in this way the blood flow, which might worsen cognitive impairments.

Question 3

Which functional networks are mostly affected by aging?

Answer 3

The frontocerebellar, the frontostriatal and the frontohippocampal circuits.

Question 4

Describe one mechanism that could explain the hippocampal atrophy in aging.

Answer 4

Neurotrophins are essential in the development of the hippocampus. With increasing age, the hippocampus becomes less sensitive to these neurotrophins, which might lead to atrophy.

Question 5

Explain the main differences between subcortical and periventricular pathways.

Answer 5

Subcortical pathways are usually short in distance, connecting intracortical or cortico-subcortical areas. They are often u-shaped.

Periventricular pathways are usually long in distance and lie adjacent to the ventricles. They connect cortex with subcortex or intracortical areas over a long distance.

Question 6

In how far do white matter lesions (periventricular) influence cognitive functioning in people >85 years of age? What might be an explanation for this?

Answer 6

There is no significant association between white matter lesions and cognitive functioning in this specific group. Younger people are, however, affected. For older people, the brain might have adapted to the white matter changes, leaving the cognitive functions unaffected.

Question 7

When there is damage to the frontostriatal circuit, the inhibition of overlearned responses is mostly deteriorated. In how far does this symptom differ in striatal damage and frontal damage?

Answer 7

In frontal damage, strongly overlearned responses are harder to inhibit, whereas in striatal damage weaker overlearned responses are harder to inhibit.

Question 8

Which cognitive functions are preserved in aging?

Answer 8

EFs: Language, abstract reasoning, visuospatial functions.

Memory: Procedural, implicit, short-term

Global cognitive functioning: automatized activities of daily living

Question 9

Which cognitive functions are impaired in frontocerebllar decline?

Answer 9

Speed of information processing and divided attention.