Developmental Homeostasis of Mouse Retinocollicular Synapses
| Autor: | Michael C. Crair, Anand R. Chandrasekaran, Ruchir D. Shah |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Superior Colliculi
N-Methylaspartate Receptors Nicotinic Biology Models Biological Retinal ganglion Retina Membrane Potentials Mice chemistry.chemical_compound Excitatory Amino Acid Agonists medicine Animals Homeostasis Visual Pathways alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Visual Cortex Mice Knockout Neurons Brain Mapping General Neuroscience Superior colliculus Retinal Articles Retinal waves Mice Inbred C57BL Visual cortex medicine.anatomical_structure Animals Newborn chemistry Receptive field Sensory maps Synapses Neuroscience |
| Zdroj: | The Journal of Neuroscience. 27:1746-1755 |
| ISSN: | 1529-2401 0270-6474 |
| DOI: | 10.1523/jneurosci.4383-06.2007 |
| Popis: | Spontaneous retinal waves during development are thought to provide an instructive signal for precise retinotopic mapping by correlating the activity of neighboring retinal ganglion cells. In mutant mice (β2−/−) that lack correlated waves, retinocollicular map refinement is impaired.In vivorecordings reveal that neurons in the superior colliculus of β2−/−mice have large receptive fields and low peak visual responses, resulting in a conservation of total integrated response. We find that this “response homeostasis” is maintained on a cell-by-cell basis, and argue that it does not depend on regulation from the visual cortex during adulthood. Instead,in vitrorecordings show that homeostasis arises from the conservation of total synaptic input from the retina, and that it is maintained via different mechanisms over development. In the absence of correlated retinal waves, β2−/−neurons sample a larger number of weaker retinal inputs relative to controls after the first postnatal week. Once retinal waves are restored, developmental learning rules and homeostasis drive refinement so that fewer, stronger synapses are retained, as in wild-type mice, but from a larger retinal area. Homeostasis in neurons has been shown previously to regulate the gain of synaptic transmission in response to perturbations of activity. Our results suggest that during the development of sensory maps, a unique consequence of homeostatic mechanisms is the precise shaping of neuronal receptive fields in conjunction with activity-dependent competition. |
| Databáze: | OpenAIRE |
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