@article {5253,
	title = {Rapid functional maturation of nascent dendritic spines.},
	journal = {Neuron},
	volume = {61},
	year = {2009},
	month = {2009 Jan 29},
	pages = {247-58},
	abstract = {<p>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 Ca(2+) imaging to analyze the properties of nascent spines and their older neighbors. 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 Ca(2+) 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.</p>
},
	keywords = {AMPA, Animals, Calcium, Calcium Signaling, Cell Differentiation, Confocal, Dendritic Spines, Electron, Glutamic Acid, Hippocampus, Microscopy, Neuronal Plasticity, Organ Culture Techniques, Patch-Clamp Techniques, Pyramidal Cells, Rats, Receptors, Synapses, Synaptic Membranes, Synaptic Transmission, Time Factors, Transmission},
	issn = {1097-4199},
	doi = {10.1016/j.neuron.2008.10.054},
	author = {Zito, Karen and Scheuss, Volker and Knott, Graham and Hill, Travis and Svoboda, Karel}
}
@article {4258,
	title = {Characterization and subcellular targeting of GCaMP-type genetically-encoded calcium indicators.},
	journal = {PLoS One},
	volume = {3},
	year = {2008},
	month = {2008 Mar 19},
	pages = {e1796},
	abstract = {<p>Genetically-encoded calcium indicators (GECIs) hold the promise of monitoring [Ca(2+)] in selected populations of neurons and in specific cellular compartments. Relating GECI fluorescence to neuronal activity requires quantitative characterization. We have characterized a promising new genetically-encoded calcium indicator-GCaMP2-in mammalian pyramidal neurons. Fluorescence changes in response to single action potentials (17+/-10\% DeltaF/F [mean+/-SD]) could be detected in some, but not all, neurons. Trains of high-frequency action potentials yielded robust responses (302+/-50\% for trains of 40 action potentials at 83 Hz). Responses were similar in acute brain slices from in utero electroporated mice, indicating that long-term expression did not interfere with GCaMP2 function. Membrane-targeted versions of GCaMP2 did not yield larger signals than their non-targeted counterparts. We further targeted GCaMP2 to dendritic spines to monitor Ca(2+) accumulations evoked by activation of synaptic NMDA receptors. We observed robust DeltaF/F responses (range: 37\%-264\%) to single spine uncaging stimuli that were correlated with NMDA receptor currents measured through a somatic patch pipette. One major drawback of GCaMP2 was its low baseline fluorescence. Our results show that GCaMP2 is improved from the previous versions of GCaMP and may be suited to detect bursts of high-frequency action potentials and synaptic currents in vivo.</p>
},
	keywords = {Action Potentials, Animals, Calcium, Hippocampus, Humans, Rats, Subcellular Fractions},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0001796},
	author = {Mao, Tianyi and O{\textquoteright}Connor, Daniel H and Scheuss, Volker and Nakai, Junichi and Svoboda, Karel}
}
