Psychology of aging' Lecture 2: Biological changes with age' Focus on the brain'

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Psychology of aging.Lecture 2 Biological
changes with age. Focus on the brain.

• Prof Louise Phillips
• PPT slides Web CT or
• Louise Phillips gt Homepage gt Level 2

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Biological changes with age

• Why do we age?

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Normal pathological aging

• Normal aging senescence
• Natural decline in bodily function
• Some cognitive decline
• Pathological aging senility
• Organic brain disorder, e.g. dementia
• Severe irreversible cognitive decline

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Maximum life span

• Jeanne Calment,
• 122 yrs 5 mths.

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Maximum life span

• Average lifespan greatly increased
• But maximum possible lifespan unchanged?
• Ways to maximise lifespan
• eat very little
• avoid stress
• have good genes
• be rich
• be a woman or at least be a married man
• live in the country
• dont smoke

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Why do we age?

• Biological theories of aging

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1 Rate of living

• Limited energy
• Caloric restriction in rats
• Slows aging process
• Can extend rat life by up to 60
• Human evidence
• Okinawans eat 60 calories of normal Japanese
  diet
• 40 times as many centenarians

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2 Cellular aging

• The Hayflick limit?
• Cells fixed number of divisions
• Importance of telomeres
• Cross linking
• Muscles, arteries, skin less flexible
• Free radicals
• Unstable molecules which may cause cellular damage

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3 Programmed cell death autoimmune response

• Genetic programme of cell suicide?
• Dying cells may trigger similar processes in
  surrounding cells.
• Immune system as an aging clock?
• Older immune system
• More infection-prone
• More autoimmune response

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Changes in brain functioning with age

• Microscopic and macroscopic changes

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Neuronal structure
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Neuronal changes with age

• Fewer neurons in older adult brains
• 5-10 loss in 65 compared to 20 yr old
• Neurofibrillary tangles increase with age
• axonal fibres tangle to form filaments
• Dendritic changes shrink with age?
• recent evidence continued dendritic growth
• Neuritic plaques increase with age
• lumps of dying neurons
• Note most studies postmortem.

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Communication amongst neurons

• No net change in number of synapses
• Neurotransmitter changes with age
• Dopamine decrease
• Acetylcholine decrease
• Impairs memory?

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Macroscopic brain changes with age

• Bromley (1988)
• Brain size decreases 10-15
• Ventricular volume increases
• Infarcts and accumulated traumas
• Localization of neuronal changes?
• Frontal lobes personality and control
• Hippocampus memory

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Frontal lobes of the brain

• Frontal lobe structure
• Neuronal shrinkage with age
• Volume at 70 17 less than at 20
• Frontal lobe function
• At rest age-related decreases in frontal lobe
  blood flow
• When carrying out memory tasks older adults show
  more frontal lobe activation than young

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Hippocampus changes with age

• Evidence of neuronal loss structural shrinkage
• Lye et al. (2004)
• Hippocampal size related to memory impairment in
  102 participants aged 81-94

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Sensory changes with age

• Vision and hearing

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Visual changes with age structure

• 75 of older adults need glasses
• Acuity declines slowly till 60, then rapidly.
• Structural changes in eye
• Decrease in light entering eye
• Adaptation to luminosity decreases
• Difficulty in near vision

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Visual changes with age retina

• Macular degeneration
• Decrease in number of visual receptor cells
• 20 of people aged over 75.

• Diabetic retinopathy
• Damage to blood flow and structure

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Changes in hearing

• 46 of older adults hearing impairment
• Changes with age
• loss of auditory neurons
• middle ear bones stiffen
• poor transmission high-frequency sounds
• poor pitch discrimination
• Interpersonal communication more difficult.
• Particular difficulty when background noise.

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Other senses

• Sense of taste
• Food tastes more bland
• Sense of smell
• Declines beyond 60
• Balance
• Dizziness and vertigo common
• Increase in falls

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Conclusions

• Age effects on biology and the brain.

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Conclusions

• Biological aging affected by
• cellular immune system changes
• Neuronal changes
• fewer neurons also tangles and plaques
• decreased neurotransmitters
• Localised brain changes
• frontal lobes and hippocampus
• Sensory changes
• impaired vision and hearing

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Questions to think about.

• Outline some of the general biological theories
  of aging.
• Which brain regions are most affected by age and
  what the psychological implications of these
  changes?
• Discuss whether all aspects of neuronal
  functioning change with age.
• To what extent do different senses decline with
  age?