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Comparison of plasticity in vivo and in vitro in the developing visual cortex of normal and protein kinase A RIbeta-deficient mice.
- Source :
-
The Journal of neuroscience : the official journal of the Society for Neuroscience [J Neurosci] 1998 Mar 15; Vol. 18 (6), pp. 2108-17. - Publication Year :
- 1998
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Abstract
- Developing sensory systems are sculpted by an activity-dependent strengthening and weakening of connections. Long-term potentiation (LTP) and depression (LTD) in vitro have been proposed to model this experience-dependent circuit refinement. We directly compared LTP and LTD induction in vitro with plasticity in vivo in the developing visual cortex of a mouse mutant of protein kinase A (PKA), a key enzyme implicated in the plasticity of a diverse array of systems. In mice lacking the RIbeta regulatory subunit of PKA, we observed three abnormalities of synaptic plasticity in layer II/III of visual cortex in vitro. These included an absence of (1) extracellularly recorded LTP, (2) depotentiation or LTD, and (3) paired-pulse facilitation. Potentiation was induced, however, by pairing low-frequency stimulation with direct depolarization of individual mutant pyramidal cells. Together these findings suggest that the LTP defect in slices lacking PKA RIbeta lies in the transmission of sufficient net excitation through the cortical circuit. Nonetheless, functional development and plasticity of visual cortical responses in vivo after monocular deprivation did not differ from normal. Moreover, the loss of all responsiveness to stimulation of the originally deprived eye in most cortical cells could be restored by reverse suture of eyelids during the critical period in both wild-type and mutant mice. Such an activity-dependent increase in response would seem to require a mechanism like potentiation in vivo. Thus, the RIbeta isoform of PKA is not essential for ocular dominance plasticity, which can proceed despite defects in several common in vitro models of neural plasticity.
- Subjects :
- Action Potentials physiology
Animals
Cyclic AMP-Dependent Protein Kinase RIbeta Subunit
Extracellular Space physiology
Functional Laterality physiology
Long-Term Potentiation physiology
Mice
Ocular Physiological Phenomena
Patch-Clamp Techniques
Reference Values
Sensory Deprivation physiology
Synapses physiology
Vision, Monocular physiology
Visual Cortex growth & development
Aging physiology
Cyclic AMP-Dependent Protein Kinases deficiency
Neuronal Plasticity physiology
Visual Cortex physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0270-6474
- Volume :
- 18
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- The Journal of neuroscience : the official journal of the Society for Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 9482797