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Cited by 1,565Neuroscience and Neuropharmacology ResearchGenetics and Neurodevelopmental DisordersMemory and Neural Mechanisms

Dendritic spine geometry is critical for AMPA receptor expression in hippocampal CA1 pyramidal neurons

Open access
Matsuzaki, Masanori, Ellis-Davies, Graham C. R., Nemoto, Tomomi, Miyashita, Yasushi, Iino, Masamitsu, Kasai, Haruo·2001·Nature Neuroscience
DOI 10.1038/nn736PMC PMC4229049
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Abstract

Dendritic spines serve as preferential sites of excitatory synaptic connections and are pleomorphic. To address the structure-function relationship of the dendritic spines, we used two-photon uncaging of glutamate to allow mapping of functional glutamate receptors at the level of the single synapse. Our analyses of the spines of CA1 pyramidal neurons reveal that AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)-type glutamate receptors are abundant (up to 150/spine) in mushroom spines but sparsely distributed in thin spines and filopodia. The latter may be serving as the structural substrates of the silent synapses that have been proposed to play roles in development and plasticity of synaptic transmission. Our data indicate that distribution of functional AMPA receptors is tightly correlated with spine geometry and that receptor activity is independently regulated at the level of single spines.

AI snapshot

Written from the paper’s full text.

TL;DR

Using two-photon uncaging of a newly developed caged glutamate, this study mapped functional AMPA receptors on individual dendritic spines of hippocampal CA1 pyramidal neurons. It finds that AMPA receptor expression is tightly correlated with spine-head geometry, with mushroom spines bearing many receptors and thin spines/filopodia few, suggesting independent regulation at single spines.

Key findings

  • AMPA-type glutamate receptors are abundant in mushroom spines (up to 150/spine) but sparsely distributed in thin spines and filopodia; thin spines and filopodia may serve as structural substrates of silent synapses.
  • Glutamate sensitivity of individual spines correlated strongly with spine-head volume: correlation coefficient r = 0.69–0.90 (0.80 ± 0.07; n = 9) within one dendrite, 0.89 in one example, and 0.77 for the average of 9 dendrites; correlation with spine length was weak and negative (r = 0.30).
  • Nonstationary fluctuation analysis estimated 46–147 AMPA receptors in mushroom spines (82 ± 31; mean ± s.d., n = 8), with single-channel currents of 0.4–0.8 pA (0.6 ± 0.1 pA); estimated opening probability was 0.27, suggesting postsynaptic AMPA receptors are not saturated by glutamate from a single vesicle.
  • Autocorrelation analysis along dendrites showed no correlation even in neighboring spines for glutamate sensitivities or spine-head volumes, suggesting AMPA receptor expression is controlled independently at the level of individual spines.

Methods

  • Two-photon uncaging of MNI-glutamate combined with whole-cell patch-clamp electrophysiology and fluorescence imaging in cultured hippocampal neurons and acute hippocampal slices from rats (cultured neurons from P1 Wistar rats, used at 17–25 days; slices from 15–22 day old Sprague–Dawley rats unless otherwise stated; some young animals 7–9 days old).
  • Functional mapping used pseudorandom scanning at 0.33 μm lateral intervals and z-axis sections separated by 0.8 μm, recording 2pEPSCs at −70 mV; spine-head volume was estimated from fluorescence images, and autocorrelation and nonstationary fluctuation analysis (with 0.1 mM cyclothiazide) were used.
  • Analysis included kinetic/diffusion modeling of glutamate concentration and AMPA receptor opening, correlation coefficients, coefficients of variation, and estimation of receptor number and single-channel current.

Limitations

  • Stated in the paper: the mechanism by which spine-head volume affects AMPA receptor trafficking remains to be determined, and whether thin spines, filopodia, and dendritic shafts transform into thicker spines after long-term potentiation is unknown. Spatial resolution in slices was slightly reduced (0.6 μm laterally and 1.4 μm axially) because of the lower numerical aperture lens, so dendrites with relatively sparse spines (~1 spine/μm) were studied; correlation values were reduced by channel noise (CV ~0.08) and sampling error (CV = 0.1).
  • Evident from the text: experiments were performed at room temperature (23–25°C), in cultured neurons or acute slices from juvenile rats, and the main structure–function relationship is correlational rather than causal; some analyses relied on small samples (e.g., n = 7–9 dendrites, n = 8 for fluctuation analysis).

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/nn736

Cites

53 of 53 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

10 of 34 cited sources checked · 3 supported · 0 flagged · accuracy not yet measured

  • Interpretationcitation
    § RESULTS

    Two-photon excitation of MNI-glutamate permits functional mapping of glutamate sensitivity with a spatiotemporal resolution similar to that achieved by activation of presynaptic terminals (~0.4 μm and ~0.1 ms).

    “Nevertheless, two-photon excitation of MNI-glutamate permits the functional mapping of glutamate sensitivity with a spatiotemporal resolution similar to that achieved by activation of presynaptic terminals (~0.4μm and ~0.1 ms)28.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [28] Rusakov, D. A. & Kullmann, D. M. Extrasynaptic glutamate diffusion in the hippocampus: ultrastructural constraints, uptake, and receptor activation. J. Neurosci. 18, 3158–3170 (1998). source

      The Synaptic currents and Activation of extrasynaptic receptors sections discuss modeled glutamate diffusion and receptor activation at distances around 400–465 nm; they do not describe the resolution of functional mapping. Searches for MNI-glutamate, two-photon excitation, and the claimed 0.1 ms resolution found no passage addressing the comparison with presynaptic-terminal activation. Page numbers were not available in our copy. (LLM, conf=0.76)

      Experimental — accuracy not yet measured
  • Interpretationown data
    § RESULTS

    The expression of AMPA receptors is controlled independently at the level of the individual spine.

    “This observation suggests that the expression of AMPA receptors is controlled independently at a level of the individual spine, consistent with the classical notion that a single spine may behave as an independent chemical compartment to regulate synaptic transmission13, 14.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [13] Harris, K. M. & Stevens, J. K. Dendritic spines of CA 1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics. J. Neurosci. 9, 2982–2997 (1989). source

      The Serial electron microscopy section (p. 2983) proposes that constricted spine necks might limit diffusion to neighboring synapses, supporting the cited notion of a spine as a possible chemical compartment. The discussion of spine geometry and synaptic efficacy (page not specified in our copy) likewise treats compartmentation as a possibility. Neither passage establishes that AMPA-receptor expression is controlled independently at each spine. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [14] Yuste, R. & Denk, W. Dendritic spines as basic functional units of neuronal integration. Nature 375, 682–684 (1995). source
  • Interpretationown data
    § DISCUSSION

    Thin spines and filopodia may be postsynaptic components of silent synapses.

    “In addition, our study suggests that thin spines and filopodia may be postsynaptic components of silent synapses28, 32, 34, 44.”
    Quote in the paperSubstantial claim2 of 4 sources checked
    • cites [28] Rusakov, D. A. & Kullmann, D. M. Extrasynaptic glutamate diffusion in the hippocampus: ultrastructural constraints, uptake, and receptor activation. J. Neurosci. 18, 3158–3170 (1998). source

      The Activation of extrasynaptic receptors section discusses NMDA-receptor activation at neighboring synapses and notes that dendritic spines may change shape, but does not identify thin spines or filopodia as components of silent synapses. Searches for “filopodia,” “thin spines,” and “silent synapses” found no passage making that connection; silent synapses appear in the References. (LLM, conf=0.74)

      Experimental — accuracy not yet measured
    • cites [32] Gomperts, S. N., Rao, A., Craig, A. M., Malenka, R. C. & Nicoll, R. A. Postsynaptically silent synapses in single neuron cultures. Neuron 21, 1443–1451 (1998). source
    • cites [34] Durand, G. M., Kovalchuk, Y. & Konnerth, A. Long-term potentiation and functional synapse induction in developing hippocampus. Nature 381, 71–75 (1996). source
    • cites [44] Fiala, J. C., Feinberg, M., Popov, V. & Harris, K. M. Synaptogenesis via dendritic filopodia in developing hippocampal area CA1. J. Neurosci. 18, 8900–8911 (1998). source

      The Results report synapses on filopodia, and the Analysis describes how the postsynaptic process was identified as a spine or filopodium. The paper also mentions thin spines, but our copy does not identify synapses on either structure as silent; that qualification is unsupported. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Findingcitation
    § RESULTS

    Regions of glutamate sensitivity tended to be asymmetrically localized to one portion of a spine.

    “Regions of glutamate sensitivity tended to be asymmetrically localized to one portion of a spine (Figs. 3h and 4c–j), consistent with the predominant localization of AMPA receptors within PSDs with a diameter of 0.1 to 0.5μm13, 19, 20.”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [13] Harris, K. M. & Stevens, J. K. Dendritic spines of CA 1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics. J. Neurosci. 9, 2982–2997 (1989). source

      The citation follows the sentence’s PSD explanation, while the asymmetric glutamate-sensitivity observation is presented as the citing paper’s own finding. In “Relationships between hippocampal spine geometry and,” Harris and Stevens describe PSDs as occupying only a small portion of spine surface and suggest that larger PSDs contain more receptors. Our copy does not establish that the receptors are specifically AMPA receptors or give the stated 0.1–0.5 μm PSD diameter. (LLM, conf=0.79)

      Experimental — accuracy not yet measured
    • cites [19] Nusser, Z. et al. Cell type and pathway dependence of synaptic AMPA receptor number and variability in the hippocampus. Neuron 21, 545–559 (1998). source

      The paper’s Figure 9 caption shows AMPA-receptor labeling at synaptic junctions on spines, supporting the localization invoked to explain the citing authors’ own glutamate-sensitivity observations. It also shows labeling in the spine apparatus and extrasynaptic membrane, and the passages do not establish the stated PSD diameter of 0.1–0.5 μm. The asymmetric glutamate-sensitivity finding is attributed to the citing paper’s figures, not to this source. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [20] Takumi, Y., Ramirez-Leon, V., Laake, P., Rinvik, E. & Ottersen, O.P. Different modes of expression of AMPA and NMDA receptors in hippocampal synapses. Nat. Neurosci. 2, 618–624 (1999). source
  • Interpretationown data
    § DISCUSSION

    The relationship between spine geometry and expression of functional AMPA receptors provides substantial support to the hypothesis that neuronal fine structures have functional correlates in the brain.

    “The relationship between spine geometry and expression of functional AMPA receptors demonstrated here provides substantial support to the hypothesis that neuronal fine structures have functional correlates in the brain13, 18, 21.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites [13] Harris, K. M. & Stevens, J. K. Dendritic spines of CA 1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics. J. Neurosci. 9, 2982–2997 (1989). source
    • cites [18] Cajal, R. y. Histologie du Systeme Nerveux de l'Homme et des Vertebres (Maloine, Paris, 1911).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [21] Segal, M., Korkotian, E. & Murphy, D. D. Dendritic spine formation and pruning: common cellular mechanisms? Trends Neurosci. 23, 53–57 (2000). source
  • May combine two claims. 13
  • Classified as probably not a substantial claim. 16

  • May combine two claims.

    Interpretationown data
    § DISCUSSION

    Given that each spine receives only one synaptic input, the data indicate that the highest possible degree of freedom is available in synaptic connections in the dendrites, which has been assumed in the learning models of most neural network theories.

    “Given that each spine receives only one synaptic input13, our data indicate the highest possible degree of freedom is available in synaptic connections in the dendrites, which has been assumed in the learning models of most neural network theories17.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [13] Harris, K. M. & Stevens, J. K. Dendritic spines of CA 1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics. J. Neurosci. 9, 2982–2997 (1989). source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [17] Arbib, M. A. The Handbook of Brain Theory and Neural Networks (MIT Press, Cambridge, Massachusetts, 1995). source

  • May combine two claims.

    Interpretationcitation
    § RESULTS

    The data are consistent with the correlation between AMPA receptor immunoreactivity and the size of PSD, because the size of PSD is nearly proportional to the spine-head volume.

    “These data are consistent with the correlation between AMPA receptor immunoreactivity and the size of PSD19, 20, because the size of PSD is nearly proportional to the spine-head volume13.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [19] Nusser, Z. et al. Cell type and pathway dependence of synaptic AMPA receptor number and variability in the hippocampus. Neuron 21, 545–559 (1998). source
    • cites [20] Takumi, Y., Ramirez-Leon, V., Laake, P., Rinvik, E. & Ottersen, O.P. Different modes of expression of AMPA and NMDA receptors in hippocampal synapses. Nat. Neurosci. 2, 618–624 (1999). source
    • cites [13] Harris, K. M. & Stevens, J. K. Dendritic spines of CA 1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics. J. Neurosci. 9, 2982–2997 (1989). source

  • May combine two claims.

    Findingown data
    § RESULTS

    MNI-glutamate did not affect the amplitude or time course of miniature excitatory postsynaptic currents, indicating that it does not exert an antagonistic effect at AMPA receptors.

    “Moreover, it did not affect either the amplitude (Fig. 1b) or the time course (Fig. 1b, inset) of miniature excitatory postsynaptic currents (mEPSCs), indicating that it does not exert an antagonistic effect at AMPA receptors.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    MNI-glutamate has a two-photon cross section of 0.06 GM, sufficiently large for biological application.

    “We developed a methoxy derivative of nitroindolino-glutamate, MNI-glutamate (Fig. 1a), that possesses a two-photon cross section (0.06 GM; 1 GM = 10−50 cm4s/photon2) sufficiently large for biological application (see Methods).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    Thin spines exhibited little or slight glutamate sensitivity, and thick mushroom spines displayed large sensitivity to uncaged glutamate.

    “Thin spines exhibited little (Fig. 4a and b) or slight glutamate sensitivity (Fig. 4c–e), and thick mushroom spines displayed large sensitivity to uncaged glutamate (Fig. 4f–j).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § RESULTS

    The spatial resolution of AMPA-receptor mapping in slices was 0.6 μm laterally and 1.4 μm axially, slightly reduced compared with cultured neurons because of the smaller numerical aperture of the lens used (0.9).

    “The spatial resolution of AMPA-receptor mapping was slightly reduced compared with cultured neurons, 0.6μm laterally and 1.4μm axially, because of the smaller numerical aperture (NA) of the lens used (0.9).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    In young animals (7 to 9 days old), dendrites were sparsely decorated with spines, and most of the dendritic shaft was devoid of glutamate sensitivity, although marked expression of functional AMPA receptors was already apparent in mushroom spines present.

    “In young animals (7 to 9 days old), dendrites were decorated only sparsely with spines34, and most of the dendritic shaft was devoid of glutamate sensitivity (Fig. 4l), although marked expression of functional AMPA receptors was already apparent in mushroom spines present (Fig. 4l).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [34] Durand, G. M., Kovalchuk, Y. & Konnerth, A. Long-term potentiation and functional synapse induction in developing hippocampus. Nature 381, 71–75 (1996). source

  • May combine two claims.

    Findingown data
    § RESULTS

    The glutamate sensitivity of each PSD, defined as the maximum glutamate sensitivity of a spine, was significantly correlated with the volume of the spine head; the correlation coefficient was 0.69-0.90 (0.80 ± 0.07; n = 9) within one dendrite (0.89) and 0.77 for the average of 9 dendrites.

    “The glutamate sensitivity of each PSD (as defined by the maximum glutamate sensitivity of a spine) was significantly correlated with the volume of the spine head (Fig. 5a); the correlation coefficient (r) was 0.69–0.90 (0.80 ± 0.07; n = 9) within one dendrite (0.89, Fig. 5b) and 0.77 for average of 9 dendrites (Fig. 5c).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The maximal glutamate sensitivity of a spine reflects the number of functional AMPA receptors in that spine.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation
    § METHODS

    The two-photon action cross section of MNI-glutamate is 0.06 GM at 730 nm, determined using azid-1 as a standard compound with a known action cross section of 1.0 GM at 730 nm.

    “The two-photon action cross section of MNI-glutamate was obtained as 0.06 GM at 730 nm, using azid-1 as a standard compound with a known action cross section of 1.0 GM at 730 nm48.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [48] Brown, E. B., Shear, J. B., Adams, S. R., Tsien, R. Y. & Webb, W. W. Photolysis of caged calcium in femtoliter volumes using two-photon excitation. Biophys. J. 76, 489–499 (1999). source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § RESULTS

    The time course of 2pEPSC in CA1 pyramidal neurons is similar to spontaneous mEPSCs.

    “The time course of 2pEPSC (Fig. 3bA–C) is similar to spontaneous mEPSCs (Fig. 3bE).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § RESULTS

    Slow NMDA-mediated currents had a less heterogeneous distribution than AMPA receptors, and most spines expressed NMDA receptors.

    “We also detected slow NMDA-mediated currents when Mg2+ was removed from the extracellular solution; the distribution of these currents was less heterogeneous than that of AMPA receptors, and most spines expressed NMDA receptors (data not shown).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § METHODS

    The peak glutamate concentration at the center of irradiation reaches 0.6 mM focally at a laser power of 7 mW, MNI-glutamate concentration of 8 mM, and irradiation duration of 50 μs.

    “For instance, the peak glutamate concentration at the center of irradiation reaches 0.6 mM focally, at a laser power of 7 mW, MNI-glutamate concentration (CMNI) of 8 mM, the duration of irradiation (td) of 50 μs.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § METHODS

    Values of τp larger than 20 μs predict greater loss of spatial resolution than actually obtained.

    “and those larger than 20 μs predict greater loss of spatial resolution than actually obtained (Fig. 1f)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation
    § RESULTS

    The evoked currents had a small coefficient of variation of 0.08, consistent with the postsynaptic action of glutamate.

    “The evoked currents had a small coefficient of variation (CV) of 0.08, consistent with the post-synaptic action of glutamate23.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] Liu, G., Choi, S. & Tsien, R. W. Variability of neurotransmitter concentration and nonsaturation of postsynaptic AMPA receptors at synapses in hippocampal cultures and slices. Neuron 22, 395–409 (1999). source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given
    § METHODS

    Under the listed conditions, the peak opening probability was 0.15 for 2pEPSC and 0.2 for mEPSC.

    “In the condition listed above, the peak opening probability was 0.15 and 0.2 for 2pEPSC and mEPSC, respectively.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § DISCUSSION

    Less effective transport of AMPA receptors into thinner spines with smaller volume-to-surface ratios might cause thin spines and filopodia to be silent.

    “This might result from less effective transport of AMPA receptors into thinner spines with smaller volume-to-surface ratios.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § METHODS

    The animal experiments were approved by the animal experiment committee of the National Institute for Physiological Sciences, Japan.

    “The animal experiments were approved by the animal experiment committee of the National Institute for Physiological Sciences, Japan.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data
    § METHODS

    The spine-head volume was estimated by total fluorescence of the spine head in fluorescence images, calibrated using a large spine head whose volume (0.087 μm3, spine A in Fig. 3f) could be directly estimated by a FWHM diameter.

    “The spine-head volume was estimated by total fluorescence of the spine head in the fluorescence images, which was calibrated using the large spine head whose volume (0.087μm3, spine A in Fig. 3f) could be directly estimated by a FWHM diameter.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning
    § METHODS

    The error due to sampling intervals was estimated as 0.1 (CV), given the spatial resolution of glutamate mapping as 0.6 μm laterally and 1.4 μm axially.

    “The error due to the sampling intervals was estimated as 0.1 (CV), given the spatial resolution of glutamate mapping as 0.6μm laterally and 1.4μm axially.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data
    § RESULTS

    The weak correlation between glutamate sensitivity and spine length may be due to the presence of several spines with long length and small spine-head volume.

    “Such a weak correlation may be due to the presence of several spines with long length and small spine-head volume (Fig. 5e).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationown data
    § RESULTS

    These data conform with the development of AMPA receptor immunoreactivity in CA1 pyramidal neurons.

    “These data conform with the development of AMPA receptor immunoreactivity in CA1 pyramidal neurons35.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [35] Petralia, R. S. et al. Selective acquisition of AMPA receptors over postnatal development suggests a molecular basis for silent synapses. Nat. Neurosci. 2, 31–36 (1999). source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § METHODS

    The point spread function of the focal volume of two-photon excitation was estimated as 0.29 μm laterally and 0.89 μm axially for the inverted microscope (NA 1.2), and 0.39 μm laterally and 1.28 μm axially for the upright microscope (NA 0.9).

    “The point spread function of the focal volume of two-photon excitation were estimated using a 0.1μm fluorescent beads as 0.29 μm (FWHM) laterally and 0.89 μm axially for the inverted microscope (NA, 1.2), and 0.39μm laterally and 1.28μm axially for the upright microscope (NA, 0.9).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given
    § METHODS

    Access resistance was 70% compensated for the experiments shown in Fig. 1c-g but not for others.

    “The access resistance was 70% compensated for the experiments shown in Fig. 1c–g but not for others.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § METHODS

    The CV of two-photon excitation was estimated to be less than 0.03, by measuring two-photon excited fluorescence of Alexa Fluor 594 hydrizide applied to slice preparations similarly to MNI-glutamate.

    “We estimated the CV of the two-photon excitation to be less than 0.03, by measuring the two-photon excited fluorescence of a polar tracer, Alexa Fluor 594 hydrizide (0.2 mM, Molecular Probes, Eugene, Oregon), applied to slice preparations similarly to MNI-glutamate.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data
    § DISCUSSION

    The expression of functional AMPA receptors among spines shows a large range (CV, 0.5), varying from minimal (silent) to those bearing more than 140 AMPA channels, and has a strong correlation with spine-head volume.

    “Using two-photon excitation of a caged-glutamate compound, we showed that the expression of functional AMPA receptors among spines shows a large range (CV, 0.5), varying from the minimal (silent) to those bearing more than 140 AMPA channels, and has a strong correlation with spine-head volume.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning
    § DISCUSSION

    Two-photon uncaging allows the optical stimulation of dendritic processes in brain slices at the level of the individual synapse.

    “This powerful approach thus allows the optical stimulation of dendritic processes in brain slices at the level of the individual synapse.”
    Quote in the paperSubstantial claim
26 of 26

  • The paper relies on this without support.

    The maximal glutamate sensitivity of a spine reflects the number of functional AMPA receptors in that spine.

    “The glutamate sensitivity of each PSD (as defined by the maximum glutamate sensitivity of a spine) was significantly correlated with the volume of the spine head (Fig. 5a);”

  • The paper relies on this without support.

    In the presence of 0.1 mM cyclothiazide, the opening probability of AMPA receptors is greater than 0.5.

    “We added the desensitization inhibitor cyclothiazide (0.1 mM, CTZ) to increase the opening probability of AMPA receptors to greater than 0.5.”

  • The paper relies on this without support.

    The largest mEPSC (~19 pA) likely occurred in the mushroom spines with the largest number of AMPA receptors (N = 147, i = 0.48 pA).

    “because the opening probability of the AMPA receptors was estimated as 0.27, given that the largest mEPSC was ~19 pA (n = 222) in our experiments, and that such mEPSC likely occurred in the mushroom spines with largest number of AMPA receptors (N = 147, i = 0.48 pA).”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Spine head size is positively correlated with mEPSC amplitude, and the functional loss of NMDA receptors in DG granule cells has been associated with impairments in pattern separation.

    “Spine head size is positively correlated with mEPSC amplitude [65], and the functional loss of NMDA receptors in DG granule cells has been associated with impairments in pattern separation [8].”

    From Arf4 Determines Dentate Gyrus-Mediated Pattern Separation by Regulating Dendritic Spine Development (2012) · cites this paper as [65]

    The Results report a positive correlation between spine-head volume and the amplitude of responses evoked by uncaged glutamate, not a measured correlation with mEPSC amplitude. The paper discusses mEPSCs separately but does not establish the specific correlation attributed to citation [65]. The DG granule-cell claim is attached to citation [8] and is not judged here. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

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Related

Authors
Matsuzaki, M., Ellis-Davies, G. C. R., Nemoto, T., Miyashita, Y., Iino, M., & Kasai, H.
Affiliations
  • National Institute for Physiological Sciences (JP)
  • The University of Tokyo (JP)
Corresponding author
Kasai, Haruo
ORCID
Venue
Nature Neuroscience
Publisher
Springer Science and Business Media LLC
Published
2001-10-22
Volume
4
Issue
11
Pages
1086-1092
ISSN
  • 1097-6256 (ISSN-L)
  • 1546-1726
DOI
10.1038/nn736
PMC
PMC4229049
OpenAlex
W1798313689
Semantic Scholar
0791a25208e00590f1e05aade330dddd88a94dc4
Cited by
1,563
References
53
Citations by year
2026: 30 · 2025: 49 · 2024: 45 · 2023: 70 · 2022: 64 · 2021: 90 · 2020: 71 · 2019: 76 · 2018: 75 · 2017: 65 · 2016: 78 · 2015: 84 · 2014: 75 · 2013: 75 · 2012: 81
FWCI
10.56
Type
journal article
Language
en
Open access
Licence
www.springer.com/tdm (tdm)
Locations
  • Nature Neuroscience (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (submittedVersion)
  • PubMed Central (submittedVersion)
Funders
National Institute of General Medical Sciences (GM 53395, R01 GM053395)
Topics
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neuropharmacology Research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetics and Neurodevelopmental Disorders
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
Keywords
dendritic spines, AMPA receptors, spine geometry, mushroom spines, filopodia, silent synapses, CA1 pyramidal neurons, hippocampus, glutamate uncaging, excitatory synapses, synaptic plasticity
MeSH terms
Animals, Cells, Cultured, Dendrites, Electrophysiology, Glutamates, Hippocampus, Indoles, Mathematics, Microscopy, Fluorescence, Photolysis, Molecular Structure, Rats, Wistar, Pyramidal Cells, Receptors, AMPA, Patch-Clamp Techniques, Glutamic Acid, Excitatory Postsynaptic Potentials, Cell Surface Extensions, Rats, In Vitro Techniques

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-12.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-12.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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