1. Rapid Functional Maturation of Nascent Dendritic Spines
- Author
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Graham Knott, Karen Zito, Volker Scheuss, Travis C. Hill, and Karel Svoboda
- Subjects
musculoskeletal diseases ,Dendritic spine ,Patch-Clamp Techniques ,Time Factors ,Neuroscience(all) ,Dendritic Spines ,Long-Term Potentiation ,Synaptic Membranes ,Glutamic Acid ,AMPA receptor ,Hippocampal-Neurons ,Biology ,Hippocampal formation ,Hippocampus ,Synaptic Transmission ,Article ,MOLNEURO ,Postnatal-Development ,Actin remodeling of neurons ,Organ Culture Techniques ,Microscopy, Electron, Transmission ,Animals ,Immunogold Localization ,Calcium Signaling ,Receptors, AMPA ,Cortex In-Vivo ,Microscopy, Confocal ,Neuronal Plasticity ,General Neuroscience ,Pyramidal Cells ,Long-term potentiation ,Cell Differentiation ,musculoskeletal system ,Individual Excitatory Synapses ,Cell biology ,Dendritic filopodia ,Rats ,Spine (zoology) ,Nmda Receptors ,Postsynaptically Silent Synapses ,Synaptic plasticity ,Synapses ,Calcium ,Neuroscience ,Synaptic Plasticity ,Dependent Plasticity - Abstract
Spine growth and retraction with synapse formation and elimination plays an important role in shaping brain circuits during development and in the adult brain. Yet the temporal relationship between spine morphogenesis and the formation of functional synapses remains poorly defined. We imaged hippocampal pyramidal neurons to identify spines of different ages. We then used two-photon glutamate uncaging, whole-cell recording, and Ca2+ imaging to analyze the properties of nascent spines and their older neighbors. We found that new spines expressed glutamate sensitive currents that were indistinguishable from mature spines of comparable volumes. Some spines exhibited negligible AMPA receptor-mediated responses, but the occurrence of these ‘silent’ spines was uncorrelated with spine age. In contrast, NMDA receptor-mediated Ca2+ accumulations were significantly lower in new spines. New spines reconstructed using electron microscopy made synapses. Our data support a model in which outgrowth and enlargement of nascent spines is tightly coupled to formation and maturation of glutamatergic synapses.
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