9- Plasticity Throughout the Lifespan Flashcards
How long does the brain retain the ability for plasticity?
Throughout the lifespan
Who studied neurogenesis?
Draganski et al, 2004
What did Draganski et al study?
Juggling training in adult humans
What did Draganski et al find?
Increased brain volume in hippocampus
How did Draganski et al see that neurogenesis effects persisted?
Neurogenesis effects still present 3 months after end of training
What did Draganski et al’s study suggest?
Adult hippocampus can grow new neurons
What did Draganski et al’s study support?
Learning from practice and experience
What are stem cells?
Building blocks for all cells
What can neural stem cells generate in the CNS?
Neural progenitor cells
What can neural stem cells in the CNS create?
New neurons and glial cells in developing and adult brains
What did Altman and Das discover about adult neurogenesis by studying the rodent brain?
Formation of new neurons in the dentate gyrus of the hippocampus
How long do new cells take to fully mature?
Up to 2 months
What suggests that neurons in the hippocampus have a role in learning and memory?
New neurons go through a phase of increased synaptic plasticity
Where does neurogenesis seem to occur mostly?
In the hippocampus
What is hippocampal neurogenesis dependent on?
Activity/environment
How is hippocampal neurogenesis regulated by?
Physiological and pharmacological stimuli
What did Maguire et al study?
London taxi drivers
What is the learning that London taxi drivers go through that causes learning through experience?
Taking ‘The Knowledge’- learning to navigate and remember routes around London
How did Maguire et al measure hippocampal volume?
MRI
Who were Maguire et al’s controls?
Bus drivers
What did Maguire et al find in London taxi drivers?
Enlarged hippocampus in more experienced drivers
What did Maguire et al’s study suggest?
Learning can promote neurogenesis
How did London taxi drivers compare to experience-matched bus drivers?
London taxi drivers had larger posterior hippocampus
What does experience of drivers correlate with?
Larger posterior hippocampus
How was neurogenesis studied in 38 medical students?
An MRI structural scan 3 months before medical exam, day after the exam, and 3 months later
How did hippocampal volume change between time points when medical students were studied?
Increased
What was studying medical students good evidence for?
Learning-induced plasticity in young adulthood
How long does maturation of new neurons require?
Several weeks to months
How did Van Praag study neurogenesis?
Lab rodents were given access to a running wheel that stimulated hippocampal neurogenesis
What result did exercise have on neurogenesis in humans?
Increasing hippocampal volume
What does the hippocampus tend to do as we age?
Shrink
What could explain why some older people have similar hippocampal volumes to individuals who are younger?
Hippocampal neurogenesis
What is hippocampal neurogenesis linked to?
Better memory in later life
Who show less decline in cognitive performance as they get older?
People who are physically active in later life
How does the brain try and maintain good function as someone ages?
Brain compensates for effects of aging
What changes take place in normal aging in the brain?
Neurochemical and synaptic changes
How much does the brain shrink on average between the ages of 20 and 90?
5% to 10%
What deteriorates in the brain in normal aging?
White matter fibres
What suggests the potential for the brain to adapt?
Some older individuals maintain excellent cognition
What do ‘cognitive reserve’ models suggest?
Brain has a ‘buffer’ and can adapt and compensate for aging
What do fMRI studies show happens to the brain as we get older?
Brain activates more brain regions with age
What led to the ‘hemispheric asymmetry reduction’?
fMRI studies show that older adults additionally recruit the other hemisphere
What can TMS be used to do?
Temporarily disrupt a brain mechanism
How is TMS applied to study compensation in the aging brain?
To left or right PFC in a recognition memory task
What was the result of TMS on subjects aged less then 45?
Disrupting the right PFC affected performance
What was the result of TMS on subjects over 50?
Disrupting either hemisphere PFC affected performance
How did evidence suggest that the brain has a compensatory mechanism in aging?
Suggestion that older adults are using both hemispheres to perform the task
What does aging do to brain structure?
Undermines it
How are compensatory mechanisms enhanced?
By stimulatory experience
What kind of structure is the brain?
A highly adaptive structure that changes in both positive and negative ways across the lifespan
What drives synaptic pruning?
Experience
What does synaptic pruning lead to?
A more efficient brain
What does experience cause in adulthood?
Reorganisation of relevant cortical areas
What does plasticity allow in adulthood?
Brain to respond to injury
What promotes neurogenesis in the hippocampus?
Experience, learning and physical exercise
What can neurogenesis in the hippocampus help maintain?
Cognitive function with aging
How is plasticity also seen in later life?
As additional brain regions are used to compensate for effects of aging
