Wk11 Neuroplasticity & Brain Damage Flashcards
what are two windows ‘periods’ which show time dependence? What do they mean?
Critical period - asbolutely essential the experience occurs Sensive period - experience in this can still have an influence outside interval
What can experience/use of neural circuits achieve? 4
Maintenance Neurogenesis Synapse formation Myellination
What does “use it or lose it” imply about nature vs nurture?
Nurture is a key part of how things are established and maintained, both are important.
what are the effects of environmentally deprived mice? 2 (neuronal + behavioural)
Fewer synapses and dendritic spines Poor depth and pattern perception
what illustrates the effect of critical periods in deprived/open eye mice?
long term deprivation is not drastically worse than short term. One week alone causes a lot of damage, little more is acquired after that
When adult rats are exposed to enriched environments where was neurogenesis found? 2
Dentate gyrus of HC + olfactory bulbs
What is associated with adult rat neurogenesis in enriched environments? 2
Exercise and interaction with environment — not enough to just sit around in the new environment
What evidence shows that exercise is superior to learning alone, for neurogenesis? When do these benefits emerge?
Van Praag et al 2000: rats in Runner and Enriched conditions had new cell survival than Learning alone. After one day learning shows new cells, but these only sustain in exercise conditions.
What did voss et al 2013 show about adult neurogenesis in enriched, running, run+enriched?
Running was a key to increasing dentate gyrus new cells
how does the object sniffing test for rats work? What does it tell us?
Rats are measured on how long they sniff three objects. 24 hrs later a new object is introduced and the sniffing time for this is assessed relative to old objects. This measures rats preferentially exploring novel objects.
What do object sniffing tests show about adult neurogenesis in rats?
Rats sniff novel objects more when exercise or enrichment are provided, but the more noticeably when Ex and En are provided together.
What was a problem with early experiments on rat adult neurogenesis? How is this controlled these days?
Exercise and enrichment were confounded. Housing is used to separate the two influences.
Does exercise induced adult neurogenesis happen in humans and where? What tasks are involved in testing this?
Yes, shown in dentate gyrus. Auditory list learning.
What happens to kittens with a shut eye from birth to 2.5mo? What does this illustrate?
no contralateral activation of ocular dominance columns. Critical period for the development of these cells.
What happens to kittens with an eye shut from 12 mo to 38 mo? What does this show?
Overall V1 cortical activity diminished but no change in ocular dominance. Sensitive period where deprivation can still have negative effects.
What are the phases of activity-dependent myelination?
- ATP is released and taken by OPC to form oligodendrocytes 2. Action potentials signal astrocytes to myelinate 3. Neuronal firing modulates adhesion molecules
Does social isolation cause reduced myelination? What the implications?
Yes. But in rats. this may be a potential mechanism for a range of psychosocial mental problems, but its a large leap to apply this to humans.
What demonstrates neuroplasticity of sensory cortex maps?
When vision is displaced through prism lenses, auditory maps compensate and shift. Within a couple of days.
Can cortical digit representation increase in adults? How long does this effect last?
Yes, increased for trained movements, but specific to that movement. Lasted up to 8 weeks without training.
What is anterograde degeneration?
From the point of damage, further connections die
What is retrograde degeneration?
Backwards from the point of damage, the cell dies
