Version history

{
  "kind": "infographic",
  "prompt": "Reported PAP-synapse coverage fractions vary from ~57% in hippocampal CA1 stratum radiatum (Ventura & Harris 1999) to ~80-90% in mouse motor/somatosensory cortex and higher values in rat cortex (Gavrilov 2018). Region and method differences (rat vs mouse; CA1 vs cortex; apposition vs leaflet contact) partially explain the spread, but the near-2x variation has direct consequences for models of glutamate spillover and synaptic isolation.",
  "provider": "other",
  "raw_fields": {
    "papers": [
      {
        "n": null,
        "doi": "10.1186/s12915-015-0176-7",
        "value": "81%",
        "method": "serial block-face scanning EM (SBEM)",
        "metric": "Fraction of dendritic spines contacted by perisynaptic astrocyte processes (PAP+)",
        "n_analyzed": null,
        "ci_or_error": null,
        "text_access": "fulltext",
        "n_definition": "dendritic spines scored for PAP contact",
        "scope_region": "mouse motor cortex, layer II",
        "study_system": "adult mouse motor cortex",
        "taxonomic_level": "spine-level EM reconstruction",
        "scope_population": "excitatory spines",
        "value_source_sentence": "Across all animals, ~81 % of spines were PAP + and ~19 % were PAP negative (PAP − ) (Fig. 5e ), consistent with findings in layer IV of the mouse barrel cortex, where only ~10 % of spines lack astrocytic coverage.",
        "experimental_conditions": "baseline (sleep/wake conditions)"
      },
      {
        "n": null,
        "doi": "10.3389/fncel.2018.00248",
        "value": "72.7%",
        "method": "serial section transmission EM, 3D reconstruction",
        "metric": "Fraction of dendritic thin spines with leaflet-contact astrocytic coverage",
        "n_analyzed": null,
        "ci_or_error": null,
        "text_access": "fulltext",
        "n_definition": "thin spines analyzed by 3D EM",
        "scope_region": "hippocampus CA1 stratum radiatum",
        "study_system": "rat hippocampus CA1 stratum radiatum",
        "taxonomic_level": "spine-level EM",
        "scope_population": "excitatory spine synapses",
        "value_source_sentence": "We found that both thin and mushroom dendritic spines are predominantly located within the area of the leaflets, but not in proximity to astrocytic branchlets (Figure 8A ). 72.7% of thin spines and 83.3% of mushroom spines were located within astrocytic leaflet area.",
        "experimental_conditions": "baseline"
      },
      {
        "n": null,
        "doi": "10.1155/2014/232105",
        "value": "90%",
        "method": "3D electron microscopy",
        "metric": "Fraction of spine synapses with PAP contact (reported from layer IV mouse somatosensory cortex)",
        "n_analyzed": null,
        "ci_or_error": null,
        "text_access": "fulltext",
        "n_definition": "synapses in 3D EM volumes",
        "scope_region": "mouse somatosensory cortex, layer IV",
        "study_system": "adult mouse somatosensory cortex",
        "taxonomic_level": "synapse-level EM",
        "scope_population": "excitatory spine synapses",
        "value_source_sentence": "In layer IV of adult mouse somatosensory cortex, 3D EM demonstrated high heterogeneity of synaptic coverage, with around 10% of spine synapses having no contact with PAPs, while the rest of the spines had an intermediate coverage (from 5% to 95% in surface apposition).",
        "experimental_conditions": "baseline"
      },
      {
        "n": null,
        "doi": "10.1523/jneurosci.19-16-06897.1999",
        "value": "57%",
        "method": "serial section EM, 3D reconstruction",
        "metric": "Fraction of hippocampal CA1 stratum radiatum synapses with astrocytic process apposition",
        "n_analyzed": null,
        "ci_or_error": "±11%",
        "text_access": "abstract_only",
        "n_definition": "synapses scored by serial EM",
        "scope_region": "rat hippocampus CA1 stratum radiatum",
        "study_system": "mature rat hippocampus (in vivo and slices)",
        "taxonomic_level": "synapse-level EM",
        "scope_population": "excitatory synapses",
        "value_source_sentence": "Only 57 +/- 11% of the synapses had astrocytic processes apposed to them.",
        "experimental_conditions": "baseline"
      }
    ],
    "comparison_id": "pap-synaptic-coverage-across-regions",
    "comparison_name": "Fraction of synapses contacted/covered by perisynaptic astrocyte processes across brain regions",
    "comparison_type": "cross-study conflict",
    "what_it_reveals": "Reported PAP-synapse coverage fractions vary from ~57% in hippocampal CA1 stratum radiatum (Ventura & Harris 1999) to ~80-90% in mouse motor/somatosensory cortex and higher values in rat cortex (Gavrilov 2018). Region and method differences (rat vs mouse; CA1 vs cortex; apposition vs leaflet contact) partially explain the spread, but the near-2x variation has direct consequences for models of glutamate spillover and synaptic isolation.",
    "homogeneity_check": {
      "caveats": [
        "Ventura & Harris 1999 measured rat hippocampus CA1 stratum radiatum, whereas Gavrilov 2018 and Bellesi 2015 measured mouse somatosensory/motor cortex — different regions and species",
        "Definitions differ: 'apposed to synapse' (Ventura 1999) vs 'PAP+ spine' (Bellesi 2015) vs 'within leaflet area' (Gavrilov 2018) — not identical measurements",
        "Bernardinelli 2014 and Popov 2021 cite review estimates rather than primary measurements in the quoted sentences"
      ],
      "n_definition_uniform": "false",
      "scope_region_uniform": "false",
      "taxonomic_level_uniform": "true",
      "scope_population_uniform": "true"
    },
    "suggested_plot_type": "forest plot"
  },
  "section_id": "section_05_evidence_package",
  "source_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewAstrocytes/blob/1a55da0634a3bc04e5688792ed12141ce271d28e/evidence/section_05_evidence_package.json",
  "target_ref": "wiki_page:computationalreviewastrocytes-05",
  "review_repo": "ComputationalReviewAstrocytes",
  "section_ref": "wiki_page:computationalreviewastrocytes-05",
  "source_path": "evidence/section_05_evidence_package.json",
  "source_refs": [
    "paper:paper-6c1ee79fd5da",
    "paper:paper-79447c102381",
    "paper:paper-8cf019918a97",
    "paper:paper-9a7bb3c49d35"
  ],
  "section_title": "Astrocytic Modulation of Synaptic Transmission",
  "source_policy": {
    "mode": "public_source_pointer_with_short_context",
    "notes": [
      "Local review repositories are read-only inputs.",
      "SciDEX stores paper metadata, structured evidence, file pointers, and short citation contexts; it does not copy full review prose."
    ],
    "source_commit_sha": "1a55da0634a3bc04e5688792ed12141ce271d28e",
    "source_repository_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewAstrocytes"
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  "generation_status": "complete",
  "review_bundle_ref": "analysis_bundle:ab-029ee9411fe2",
  "origin_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewAstrocytes/blob/1a55da0634a3bc04e5688792ed12141ce271d28e/evidence/section_05_evidence_package.json",
  "commit_sha": "1a55da0634a3bc04e5688792ed12141ce271d28e",
  "created_by": "persona-jerome-lecoq-gbo-neuroscience",
  "repository_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewAstrocytes"
}