Von Bartheld: Plasticity Flashcards
Muscle fibers initially receive innervation from (blank) neurons, but following a period of elimination of synapses, each mature muscle fiber receives innervation from only (blank) neuron
several; one
*Similar elimination of polyneural innervation occurs in ganglia and among climbing fibers that innervate Purkinje cells in the cerebellum
(blank) require a certain minimal level of trophic support to persist.
synapses
Relevant factors are secreted in limited amounts by the (blank) cells in response to synaptic activation.
target cells *postsynaptic
Synapses can utilize trophic support only if their activity and that of the (blank) coincide.
target cell
Depriving an animal of normal visual experience during a restricted period of early postnatal life irreversibly alters (blank) in the visual cortex
neuronal connections
The brain translates the effects of early experience (neural activity) into (blank).
permanently altered wiring
Information from the two eyes is first integrated in the (blank) where afferent fibers from the lateral geniculate nucleus terminate. The afferent terminals form an alternating series of eye-specific domains in cortical layer IV, called (blank).
primary visual cortex; ocular dominance columns
While the input from LGN to layer IV is still segregated (eye- specific), cells at the border of layer IV and in layers above and below layer IV integrate inputs from (blank), responding to binocular visual stimuli
both eyes
Anatomical studies have shown that monocular deprivation changes the ocular dominance columns such that the columns of the deprived eye (blank), and the ones related to the open eye (blank).
shrink; expand
When individual geniculocortical terminals are examined, the ones from the deprived eye have reduced arborizations in layer IV, while the ones from the open eye are normal or hypertrophic. Thus, input from the (blank) eye takes over some of the territory from the (blank) eye
active; deprived
*this can be interpreted as a competition between the inputs from the two eyes, and the ones from the active eye have a competitive advantage over the ones from the deprived eye.
Roughly equal numbers of cells in the visual cortex respond to the right or the left eye. This normal distribution is altered by closure of one eye (monocular deprivation) during a (blank) period
critical postnatal
If you deprive an eye of vision during the postnatal critical period, very few cells can be driven from the deprived eye. The peripheral visual pathways (retina and lateral geniculate nucleus) remain normal. Thus, the deprived eye becomes functionally disconnected from the (blank), and can cause functional blindness in the deprived eye. This cortical blindness is permanent. The same manipulation, monocular deprivation, in the adult has no effect on the response of neurons in (blank). The cortical neurons are susceptible to monocular deprivation only during a certain (blank) of development.
visual cortex; visual cortex; critical period
What’s this?
“Coordinated activity of a presynaptic terminal and a postsynaptic neuron will strengthen the synaptic connection between them.” Or: synaptic terminals strengthened by correlated activity will be retained or sprout new branches, while those that are weakened by uncorrelated activity are eliminated.
Hebbs’ postulate
Accordingly, ocular dominance columns are generated by cooperation between inputs carrying (blank), and by competition between inputs carrying (blank)
similar patterns of activity; dissimilar patterns
Strabismus is a condition in which one eye muscle is dysfunctional so that the two eyes are not aligned. While the amount of activity in the two eyes stays the same, the (blank) of activity is different. This leads to a (blank) of the ocular dominance columns, and to a (blank) of the binocular neurons in the cortex
pattern; sharpening; loss