Super-resolution 2-photon microscopy reveals that the morphology of each dendritic spine correlates with diffusive but not synaptic properties

The structure of dendritic spines suggests a specialized function in compartmentalizing synaptic signals near active synapses. Indeed, theoretical and experimental analyses indicate that the diffusive resistance of the spine neck is sufficient to effectively compartmentalize some signaling molecules in a spine for the duration of their activated lifetime. Here we describe the application of 2-photon microscopy combined with stimulated emission depletion (STED-2P) to the biophysical study of the relationship between synaptic signals and spine morphology, demonstrating the utility of combining STED-2P with modern optical and electrophysiological techniques. Morphological determinants of fluorescence recovery time were identified and evaluated within the context of a simple compartmental model describing diffusive transfer between spine and dendrite. Correlations between the neck geometry and the amplitude of synaptic potentials and calcium transients evoked by 2-photon glutamate uncaging were also investigated.

[1]  K. Svoboda,et al.  The Life Cycle of Ca2+ Ions in Dendritic Spines , 2002, Neuron.

[2]  Mikrobiologie.  Activity-dependent plasticity , 2010 .

[3]  Bernardo L Sabatini,et al.  Live-cell superresolution imaging by pulsed STED two-photon excitation microscopy. , 2013, Biophysical journal.

[4]  C. Koch,et al.  The function of dendritic spines: devices subserving biochemical rather than electrical compartmentalization , 1993, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[5]  Rafael Yuste,et al.  On the electrical function of dendritic spines , 2004, Trends in Neurosciences.

[6]  Ryohei Yasuda,et al.  Local, persistent activation of Rho GTPases during plasticity of single dendritic spines , 2011, Nature.

[7]  R. Yasuda,et al.  The mechanisms underlying the spatial spreading of signaling activity , 2011, Current Opinion in Neurobiology.

[8]  Vincent A. Pieribone,et al.  Single Action Potentials and Subthreshold Electrical Events Imaged in Neurons with a Fluorescent Protein Voltage Probe , 2012, Neuron.

[9]  Bernardo L Sabatini,et al.  Neuronal Activity Regulates Diffusion Across the Neck of Dendritic Spines , 2005, Science.

[10]  J. Nitsche,et al.  A transient diffusion model yields unitary gap junctional permeabilities from images of cell-to-cell fluorescent dye transfer between Xenopus oocytes. , 2004, Biophysical journal.

[11]  Bernardo L Sabatini,et al.  Regulation of neuronal morphology and function by the tumor suppressors Tsc1 and Tsc2 , 2005, Nature Neuroscience.

[12]  E. Friedman.  Life cycle. , 2003, Health Forum journal.

[13]  Bernardo L Sabatini,et al.  Synapse-specific plasticity and compartmentalized signaling in cerebellar stellate cells , 2006, Nature Neuroscience.

[14]  Bernardo L. Sabatini,et al.  Supraresolution Imaging in Brain Slices using Stimulated-Emission Depletion Two-Photon Laser Scanning Microscopy , 2009, Neuron.

[15]  Mark A. Jervis,et al.  The Life-cycle , 1996 .

[16]  Karel Svoboda,et al.  The Spread of Ras Activity Triggered by Activation of a Single Dendritic Spine , 2008, Science.

[17]  D W Tank,et al.  Direct Measurement of Coupling Between Dendritic Spines and Shafts , 1996, Science.

[18]  KM Harris,et al.  Dendritic spines of CA 1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics , 1989, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[19]  Karel Svoboda,et al.  Activity-Dependent Plasticity of the NMDA-Receptor Fractional Ca2+ Current , 2007, Neuron.

[20]  Roberto Araya,et al.  The spine neck filters membrane potentials , 2006, Proceedings of the National Academy of Sciences.

[21]  Nelson Spruston,et al.  Synaptic amplification by dendritic spines enhances input cooperativity , 2012, Nature.

[22]  Karel Svoboda,et al.  Locally dynamic synaptic learning rules in pyramidal neuron dendrites , 2007, Nature.

[23]  David Holcman,et al.  Diffusion laws in dendritic spines , 2011, Journal of mathematical neuroscience.

[24]  G. Stuart,et al.  Membrane Potential Changes in Dendritic Spines during Action Potentials and Synaptic Input , 2009, The Journal of Neuroscience.

[25]  Nicholas T. Carnevale,et al.  Electrical Advantages of Dendritic Spines , 2012, PloS one.

[26]  Shaomin Li,et al.  Amyloid-β protein dimers isolated directly from Alzheimer's brains impair synaptic plasticity and memory , 2008, Nature Medicine.

[27]  B. Sabatini,et al.  Nonlinear Regulation of Unitary Synaptic Signals by CaV2.3 Voltage-Sensitive Calcium Channels Located in Dendritic Spines , 2007, Neuron.

[28]  Jun Noguchi,et al.  Spine-Neck Geometry Determines NMDA Receptor-Dependent Ca2+ Signaling in Dendrites , 2005, Neuron.

[29]  Yi Zuo,et al.  Spine Neck Plasticity Controls Postsynaptic Calcium Signals through Electrical Compartmentalization , 2008, The Journal of Neuroscience.

[30]  D. Maclaurin,et al.  Optical recording of action potentials in mammalian neurons using a microbial rhodopsin , 2011, Nature Methods.

[31]  W. Denk,et al.  Dendritic spines as basic functional units of neuronal integration , 1995, Nature.

[32]  U Valentin Nägerl,et al.  Two-photon excitation STED microscopy in two colors in acute brain slices. , 2013, Biophysical journal.

[33]  G. Ellis‐Davies,et al.  Structural basis of long-term potentiation in single dendritic spines , 2004, Nature.

[34]  Bernardo L Sabatini,et al.  Anatomical and physiological plasticity of dendritic spines. , 2007, Annual review of neuroscience.

[35]  Bernardo L. Sabatini,et al.  Biphasic Synaptic Ca Influx Arising from Compartmentalized Electrical Signals in Dendritic Spines , 2009, PLoS biology.