Various conditions lead to long-term changes in the visual cortex, if they occur during a critical period that lasts from eye opening to just before puberty. These long-term changes are controlled by electrical activity reaching the visual cortex from the two retinas, and involve elimination of some synapses and formation of others, together with changes in axon terminals. Considerable work on long-term potentiation, as well as plasticity in the visual cortex, suggests that electrical activity activates a series of steps that includes release of glutamate, activation of glutamate receptors, second messengers, protein kinases and phosphatases, transcription factors, and synthesis of proteins that are involved in synapse formation and elimination. Several substances may be involved at each step. The long-term objective of this application if to determine which substances are involved, which are not, to what degree those involved act in parallel and at which points there is a convergence of actions mediated by a single substance. This application uses the shift in ocular dominance that occurs with monocular deprivation to test a series of hypotheses: 1) that NMDA and metabotropic glutamate receptors act in parallel; 2) that protein kinase A is crucial substance upon which the actions of several substances converge (and thus that antagonists of PKA block plasticity altogether); 3) that Group II metabotropic receptors play an important role in the normal segregation of afferents from the lateral geniculate nucleus to the visual cortex.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY000053-33
Application #
6363093
Study Section
Visual Sciences B Study Section (VISB)
Program Officer
Oberdorfer, Michael
Project Start
1992-09-01
Project End
2004-02-29
Budget Start
2001-03-01
Budget End
2002-02-28
Support Year
33
Fiscal Year
2001
Total Cost
$387,320
Indirect Cost
Name
Yale University
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Yang, Yupeng; Fischer, Quentin S; Zhang, Ying et al. (2005) Reversible blockade of experience-dependent plasticity by calcineurin in mouse visual cortex. Nat Neurosci 8:791-6
Fischer, Quentin S; Beaver, Christopher J; Yang, Yupeng et al. (2004) Requirement for the RIIbeta isoform of PKA, but not calcium-stimulated adenylyl cyclase, in visual cortical plasticity. J Neurosci 24:9049-58
Rao, Yan; Daw, Nigel W (2004) Layer variations of long-term depression in rat visual cortex. J Neurophysiol 92:2652-8
Rao, Yan; Fischer, Quentin S; Yang, Yupeng et al. (2004) Reduced ocular dominance plasticity and long-term potentiation in the developing visual cortex of protein kinase A RII alpha mutant mice. Eur J Neurosci 20:837-42
Shimegi, Satoshi; Fischer, Quentin S; Yang, Yupeng et al. (2003) Blockade of cyclic AMP-dependent protein kinase does not prevent the reverse ocular dominance shift in kitten visual cortex. J Neurophysiol 90:4027-32
Beaver, Chris J; Fischer, Quentin S; Ji, Qinghua et al. (2002) Orientation selectivity is reduced by monocular deprivation in combination with PKA inhibitors. J Neurophysiol 88:1933-40
Reid, S N; Romano, C (2001) Developmental and sensory-dependent changes of group II metabotropic glutamate receptors. J Comp Neurol 429:270-6
Beaver, C J; Ji, Q; Daw, N W (2001) Layer differences in the effect of monocular vision in light- and dark-reared kittens. Vis Neurosci 18:811-20
Beaver, C J; Ji, Q; Fischer, Q S et al. (2001) Cyclic AMP-dependent protein kinase mediates ocular dominance shifts in cat visual cortex. Nat Neurosci 4:159-63
Daw, N W; Gordon, B; Fox, K D et al. (1999) Injection of MK-801 affects ocular dominance shifts more than visual activity. J Neurophysiol 81:204-15

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