Developmental Neurobiology: Postnatal Flashcards
How are areas of ocular dominance arranged in layer IV of V1?
Arranged into alternating columns of occular dominance, each corresponding to one eye.
How can you test, experimentally where inputs from a single eye are ending up in V1?
Inject radiolabeled amino acids (proline) into vitreous humor. Axonal transport will bring them all the way back to V1, where a banding pattern corresponding to alternating columns of ocular dominance is made.
What does the formation of ocular dominance columns not depend upon? What does it depend upon?
Does not require visual experience.
Does require spontaneous firing of neurons.
Suturing one eye shut from birth for whole critical period of visual development causes…
More neurons to become dominated by open eye…
Does binocular deprivation (suturing both eyes shut) cause a change in ocular dominance distribution?
Nope.
How do the LGN neurons receiving input from a deprived eye change?
Their axonal branches become dwindled and shrunked.
What is the critical period for visual development in humans?
1st year especially
but… may continue through years 5-9.
Critical period for human language development?
2-7 years.
First year for phoneme recognition.
What 2 broad processes make up the cellular basis for activity-dependent plasticity during critical periods?
Mechanisms that weaken and strengthen excitatory synapses.
A balance of inhibition and excitation within the cortex.
Hebb’s postulates for learning stated simply?
Cells that fire together wire together. -> long term potentiation (LTP)
Neurons out of sync lose their link. -> long term depression (LTD)
(recall that the mechanism for this involves simultaneous influx of ions through AMPA and NMDA receptors)
What’s the relationship between GABAergic neurons and the critical period? What happens if you increase their activity? Decrease it?
GABAergic neurons are necessary for opening the critical period.
Activating them makes the critical period start sooner.
Inhibiting them delays the beginning of the critical period.
How can the GABAergic neurons involved with the critical period be activated in an experimental setting?
Benzodiazepine. BDNF overexpression (low-yield details)
What role do GABAergic cells play in increasing competition of ocular dominance?
“Filtering” increases the contrast in the competition…
What does plasticity in neurodevelopment have in common with memory formation?
PKA / Cam Kinase II
ERK CREB transcription factors
