{
"name": "cortical_astrocyte_diversity_timeline_2009_2025",
"metric": "reported astrocyte subtype count and method",
"papers": [
{
"doi": "10.1523/jneurosci.4707-08.2009",
"year": 2009,
"title": "Uniquely hominid features of adult human astrocytes.",
"value": "identified 2 novel human-specific astrocyte morphotypes (interlaminar, varicose projection) beyond the classical protoplasmic/fibrous types",
"metric": "morphological subtype discovery",
"study_system": "human (immunohistochemistry, acute slice)",
"value_source_sentence": "The human neocortex also harbors several anatomically defined subclasses of astrocytes not represented in rodents."
},
{
"doi": "10.1126/science.aaa1934",
"year": 2015,
"title": "Brain structure. Cell types in the mouse cortex and hippocampus revealed by single-cell RN",
"value": "47 molecularly distinct subclasses (first large-scale cortical scRNA-seq; 2 astrocyte clusters)",
"metric": "overall cortical cell subclass count",
"study_system": "mouse (scRNA-seq, 10x)",
"value_source_sentence": "We found 47 molecularly distinct subclasses, comprising all known major cell types in the cortex."
},
{
"doi": "10.1038/s41467-019-14198-8",
"year": 2020,
"title": "Identification of region-specific astrocyte subtypes at single cell resolution.",
"value": "5 molecularly distinct astrocyte subtypes (AST1–5)",
"metric": "astrocyte subtype count (scRNA-seq, forebrain)",
"study_system": "mouse (scRNA-seq, Smart-Seq2)",
"value_source_sentence": "This led to the identification of five distinct Astrocyte SubTypes (AST1–5), each distinguished by a gene expression fingerprint (Fig."
},
{
"doi": "10.1038/s41593-020-0602-1",
"year": 2020,
"title": "Astrocyte layers in the mammalian cerebral cortex revealed by a single-cell in situ transc",
"value": "3 layer-graded identities (superficial/mid/deep); 2 clusters by unsupervised clustering",
"metric": "astrocyte subtype count (spatial + scRNA-seq, cortex)",
"study_system": "mouse (LaST-map in situ transcriptomics + smFISH + scRNA-seq)",
"value_source_sentence": "Screening 46 candidate genes for astrocyte diversity across the mouse cortex, we identified superficial, mid and deep astrocyte identities in gradient layer patterns that were distinct from those of neurons."
},
{
"doi": "10.1038/s41593-024-01743-y",
"year": 2024,
"title": "Characteristics of blood-brain barrier heterogeneity between brain regions revealed by pro",
"value": "4 astrocyte subtypes (1 cortex + 3 median eminence)",
"metric": "astrocyte subtype count (scRNA-seq, CVO + cortex)",
"study_system": "mouse (scRNA-seq, spatial transcriptomics, EM)",
"value_source_sentence": "Subclustering analysis identified four astrocyte subtypes, one from the cortex and three from the ME (Fig."
},
{
"doi": "10.1038/s41467-025-61829-4",
"year": 2025,
"title": "Dual lineage origins contribute to neocortical astrocyte diversity.",
"value": "5 molecularly distinct cortical astrocyte subtypes with layered localization",
"metric": "astrocyte subtype count (scRNA-seq + spatial, mouse neocortex)",
"study_system": "mouse (scRNA-seq, spatial transcriptomics)",
"value_source_sentence": "These methods allowed us to identify five molecularly distinct astrocyte subtypes in the mouse neocortex, each with unique localizations along the cortical column and distinct predicted functions."
}
],
"x_axis": "year",
"y_axis": "subtype count / taxonomy level",
"description": "Timeline of landmark studies establishing and refining the taxonomy of cortical astrocytes from 2009 through 2025, indicating key method advances (immunohistochemistry → scRNA-seq → spatial transcriptomics → MERFISH) and the evolving number of described subtypes from 2 discrete classes to 5–7 molecular subtypes with layer/column gradients.",
"figure_type": "timeline",
"homogeneity_check": {
"caveats": "Timeline spans methodologically heterogeneous studies. Oberheim 2009 reports morphological subtypes from human immunohistochemistry; Zeisel 2015 reports transcriptomic subclasses from mouse cortex/hippocampus; Batiuk 2020 used Smart-Seq2 on forebrain; Bayraktar 2020 used spatial transcriptomics on cortex; 2024-2025 papers incorporate MERFISH and higher-throughput 10x. Direct cross-year comparison of subtype counts is not meaningful because the units differ (morphological class vs transcriptomic cluster vs spatial gradient), and because deeper sequencing and larger cell numbers systematically increase resolvable clusters (Supplementary discussion in Batiuk 2020). The timeline is useful for understanding method-driven taxonomy evolution, not for inferring absolute numbers of true astrocyte types.",
"metric_uniform": false,
"scope_region_uniform": false,
"taxonomic_level_uniform": false,
"scope_population_uniform": false
}
}