Neuroplasticity and Amblyopia Flashcards
neuroplasticity
the ability of the brain to change, for better or for worse throughout life
involves forming neuronal connection in response to stimuli
synaptic plasticity
changes in the strength of connections between synapses
synaptogenesis
creation of groups of synapses - builds connections between neurons respectively
neuronal migration
process whereby neurons extend from their place of birth to connect to far-reaching areas of the brain
neurogenesis
creation of new neurons - occurs more in children than in adults
neural cell death
neurons die from damage, over-excitation, or disease -
brain remodeling
repetition, correct fundamentals, authentic environment
perceptual learning
phenomenon which causes an improvement in performing a particular task accurately by practicing it for several times
takes more time
motor learning
phenomenon that causes an improvement in motor skills with practicing
takes less time
Hebbian learning
“synaptic plasticity” two cells that are repeatedly active at the same time will tend to become “associated” with each other - increase efficacy
short term plasticity
primarily functional and synaptic changes
long term plasticity
needs persistent structural modifications
NMDA (N-methyl, D-aspartate)
mediates bidirectional plasticity
GABA (gamma-aminobutyric acid)
required for a critical period
BDNF (Brain-derived neurotrophic factor)
decreases inhibition and can shift critical period back
structural plasticity
changes in neuronal morphology - long term/new system
suppression and creation of synapse and genesis of new neurons and neurites
tPA (tissue plasminogen activator)
plays a role in structural plasticity
CSPGS (Chondroitin sulfate proteoglycans)
inhibit axonal growth
critical period
plasticity maximum - has maximum effect (beneficial or detrimental)
critical period
plasticity maximum - has maximum effect (beneficial or detrimental)
amblyopia
“lazy eye” - vision in one eye is reduced because the eye and the brain are not working together properly
3 major causes of amblyopia
defocus, strabismus, deprivation of stimuli
functional abnormalities in amblyopia
slower binocular reading, reduced fine motor skills, reduced motor performance in manual dexterity
impaired monocular visual function of amblyopia
acuity, reduced contrast sensitivity, spatial distortion
impaired binocular visual function of amblyopia
suppression, impaired or absent stereopsis
color vision changes in amblyopia
significant changes in red/green cone function
Is amblyopia primarily pavo, magno, or konio-cellular
Parvocellular
critical period of visual development
birth to 6 month
sensitive period
6 months to 8 years
susceptible period
8 to 18 years
residual plasticity period
18 years through adulthood
improving amblyopia in adults
perceptual learning task
hebbian competition
stronger input signals are favored/unused are pruned
normal binocular development requirement
binocular visual experience AND aligned visual axes
location of amblyopic deficit
LGN - reduced grey matter
amblyopia - loss of which contrast response - high or low?
high (parvo deficit)
crowding
multiple stimulus = difficult focus = reduced performance
need a single letter chart to test VA - difficult reading multi-letter snellen chart
