6C. Adult and Aging Brain Flashcards
Changes in grey and white matter between childhood and adulthood
Grey matter decreases as excess neurons are pruned. White matter increases as connections between separate brain areas are strengthened
When does the rate of pruning begin to slow down?
Late 20s
When does white matter volume peak?
Age 40
How are brain networks organized during childhood and adolescence?
More locally organized
When does intelligence peak?
Ages 25 to 60
Fluid intelligence
Problem solving and pattern identification. Peaks around 30
Crystallized intelligence
Vocabulary and knowledge of facts. Increases until 50
There is no single age at which all cognitive functions are at their peak. True or false?
True
Widespread and profound loss of neurons is part of normal aging. True or false?
False
When does cognition start declining?
Some say 20s to 30s, some say 50s to 60s
Most common cognitive change
Memory decline
How are the different types of memory and attention affected?
Declarative memory declines, nondeclarative memory remains intact, working memory declines starting at 30. Selective attention and divided attention decline
When does brain volume begin to decline?
Around 30s to 40s, starts declining at a greater rate around 60
Brain regions that exhibit the greatest loss in volume
PFC, cerebellum, hippocampus
Changes at cellular level that contribute to decrease in volume
Shrinking neurons, retraction and decreased complexity of dendrites, loss of myelin
Regions where thinning of cerebral cortex is most pronounced
Frontal lobes and parts of temporal lobes
Last in, first out theory
Last parts of brain to develop are the first to deteriorate. Temporal and frontal lobes show greatest declines in volume and cortical thickness, and are also the areas that take the longest to reach maturity. Fibres that are the last to mature also deteriorate first.
Synaptic changes have a greater effect than structural and chemical changes. True or false?
True
Study in rhesus monkeys observed that the aging process targets…
Thin spines. Small and slender, highly plastic, extend and retract faster than larger “mushroom” spines. Led to speculation that thin spines are involved in working memory, which requires a high degree of plasticity.
Two regions that continue to add new neurons throughout life
Olfactory bulbs and dentate gyrus of hippocampus
Two neurotransmitters decline with age
Dopamine and serotonin
Genes that are expressed less in older brains
Genes important for plasticity
Describe effect of oxidative stress on DNA
Mitochondria produce free radicals as byproducts, will destroy fats, proteins, and DNA if left unchecked. Defense mechanisms against free radicals decline with age. Damage to mDNA in brain cells accumulates.
2 factors that make the brain more vulnerable to changes
Large energy requirements (20% of body’s fuel). Neurons aren’t replaced as often as other cells.
Immune dysfunction
Microglia become more reactive.
Diets linked to better brain health
Mediterranean, DASH (dietary approaches to stop hypertension)
Nutrients linked to better brain health
Antioxidants (vitamins C and E), flavonoids, omega-3
Exercise is linked to…
Reduced cortical thinning and less shrinkage in hippocampus. Improves neuroplasticity and neurogenesis. Improves blood flow and increases production of neurotrophic factors.
